Publikacje odnotowane przez trzy miesiące

1.Jurczak G., Dłużewski P., Finite element modelling of threading dislocation effect on polar GaN/AlN quantum dot, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, ISSN: 1386-9477, DOI: 10.1016/j.physe.2017.08.018, Vol.95, pp.11-15, 2018
Jurczak G., Dłużewski P., Finite element modelling of threading dislocation effect on polar GaN/AlN quantum dot, PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES, ISSN: 1386-9477, DOI: 10.1016/j.physe.2017.08.018, Vol.95, pp.11-15, 2018

Abstract:
In this paper the effect of adjacent threading dislocation at the edge of the GaN/AlN quantum dot is analysed by use of the finite element analysis. Elastic as well electric effects related to dislocation core are taken into account. Two types of threading dislocations: edge- and screw-type, common for III-nitride epitaxial layers, are considered. Also, three different QD geometries are considered to estimate the impact of the threading dislocation on the quantum heterostructure. It is demonstrated that the local elastic and electric fields around dislocation affect local piezoelectric fields built-in the quantum dot. Local lattice deformation near the dislocation core reduce residual strains in the quantum dot. It is prominent in the case of edge-type dislocation. The presence of an electric charge along dislocation line provides significant shift of the total potential towards the negative values. However, estimated difference in band-to-band transition energy for edge- and screw-type dislocations are rather small, what suggest low sensitivity to the charge density along dislocation line. Unexpectedly, local strain field around the edge-type dislocation, slightly compensate the negative affect of the electrostatic potential.

Keywords:
Quantum dot, Threading dislocation, Piezoelectricity, Finite element modelling

2.Pisarski D., Decentralized stabilization of semi-active vibrating structures, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694-705, 2017
Pisarski D., Decentralized stabilization of semi-active vibrating structures, MECHANICAL SYSTEMS AND SIGNAL PROCESSING, ISSN: 0888-3270, DOI: 10.1016/j.ymssp.2017.08.003, Vol.100, pp.694-705, 2017

Abstract:
A novel method of decentralized structural vibration control is presented. The control is assumed to be realized by a semi-active device. The objective is to stabilize a vibrating system with the optimal rates of decrease of the energy. The controller relies on an easily implemented decentralized switched state-feedback control law. It uses a set of communication channels to exchange the state information between the neighboring subcontrollers. The performance of the designed method is validated by means of numerical experiments performed for a double cantilever system equipped with a set of elastomers with controlled viscoelastic properties. In terms of the assumed objectives, the proposed control strategy significantly outperforms the passive damping cases and is competitive with a standard centralized control. The presented methodology can be applied to a class of bilinear control systems concerned with smart structural elements.

Keywords:
structural control, decentralized control, smart structures, modular structures, stabilization

(45p.)
3.Urbanek O., Sajkiewicz P., Pierini F., The effect of polarity in the electrospinning process on PCL/chitosan nanofibres' structure, properties and efficiency of surface modification, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2017.07.064, Vol.124, pp.168-175, 2017
Urbanek O., Sajkiewicz P., Pierini F., The effect of polarity in the electrospinning process on PCL/chitosan nanofibres' structure, properties and efficiency of surface modification, POLYMER, ISSN: 0032-3861, DOI: 10.1016/j.polymer.2017.07.064, Vol.124, pp.168-175, 2017

Abstract:
The aim of this research was to study the effect of charge polarity applied to the spinning nozzle on the structure and properties of polycaprolactone/chitosan (PCL/CHT) blends, in particular the efficiency of further surface modification by chondroitin sulphate (CS). The observed differences in the morphology and properties of fibres formed at different polarities were interpreted in terms of molecular interactions occurring in the system. FTIR results indicate stronger PCL-chitosan interactions at negative polarity, resulting in lower PCL crystallinity and crystal size distribution determined by DSC, as well as lower wettability. The charge polarity influences PCL/CHT fibre morphology and tailors some of their properties, e.g. wettability, mechanical properties and the efficiency of surface modification. Better efficiency of CS attachment was observed at negative polarity using atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) is most probably related to higher chitosan content at the fibres' surface being attracted by the negative external potential.

Keywords:
Polycaprolactone/chitosan nanofibres, Charge potential effect in electrospinning, Polycaprolactone-chitosan interactions

(40p.)
4.Ryś M., Skoczeń B., Coupled constitutive model of damage affected two-phase continuum, MECHANICS OF MATERIALS, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2017.08.015, Vol.115, pp.1-15, 2017
Ryś M., Skoczeń B., Coupled constitutive model of damage affected two-phase continuum, MECHANICS OF MATERIALS, ISSN: 0167-6636, DOI: 10.1016/j.mechmat.2017.08.015, Vol.115, pp.1-15, 2017

Abstract:
A broad class of metastable materials, including selected alloys (e.g. stainless steels) used for applications in radiation environment (particle accelerators), is characterized by simultaneous occurrence of the plastic strain driven phase transformation and evolution of nano/micro damage. Plastic flow in such materials is usually accompanied by dynamic evolution of microstructure, resulting from the strain induced fcc-bcc phase transformation. Two-phase continuum is composed of austenitic matrix (fcc) and martensitic inclusions (bcc), represented by type Eshelby ellipsoidal entities embedded in ductile matrix. The matrix remains entirely plastic, and contains micro-cracks and micro-voids representing ductile damage. On the other hand, the inclusions are characterized by much higher yield stress and their behavior is generally brittle. Thus, brittle damage develops in the inclusions. The origin of damage is mechanical (manufacturing and load induced defects), and related to the source of radiation (primary or secondary particles flux). Among the lattice defects induced by radiation, the clusters of nano/micro voids are accounted for. The constitutive model takes into account the evolution of mechanically and radiation induced nano/micro damage in the presence of microstructure evolution, reflected by the plastic strain driven dynamic change of proportions between the matrix and the inclusions. The model is multiscale since the processes that occur at different scales (micro, meso, macro) are addressed, and coupled, since both phenomena: phase transformation and damage are described by coupled equations. Application to irradiated corrugated shells, components of thermo-mechanical compensation systems, are presented.

(40p.)
5.Ranachowski Z., Schabowicz K., The contribution of fiber reinforcement system to the overall toughness of cellulose fiber concrete panels, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2017.09.067, Vol.156, pp.1028-1034, 2017
Ranachowski Z., Schabowicz K., The contribution of fiber reinforcement system to the overall toughness of cellulose fiber concrete panels, CONSTRUCTION AND BUILDING MATERIALS, ISSN: 0950-0618, DOI: 10.1016/j.conbuildmat.2017.09.067, Vol.156, pp.1028-1034, 2017

Abstract:
The paper concerns the role of cellulose reinforcements in overall mechanical toughness of fiber concrete panels applied as facade building material. The results of mechanical tests performed on specimens in as delivered state as well as on specimens which underwent the procedure of destruction of internal fiber network structure due to pyrolysis are presented. The results of mechanical tests let the authors to calculate the work of fracture for six different mechanical conditions. Moreover the analysis of registered Acoustic Emission (AE) signal had revealed that the investigated process of destruction begins with the brittle crack generation and growth while major damages of reinforcement system appears in later phase of the process.

Keywords:
Fiber cement panels, Cellulose fibers, Brittle crack, Acoustic Emission

(40p.)
6.Piechocka I.K., Kurniawan N.A., Grimbergen J., Koopman J., Koenderink G.H., Recombinant fibrinogen reveals the differential roles of α- and γ-chain cross-linking and molecular heterogeneity in fibrin clot strain-stiffening, Journal of Thrombosis and Haemostasis, ISSN: 1538-7933, DOI: 10.1111/jth.13650, Vol.15, No.5, pp.938-949, 2017
Piechocka I.K., Kurniawan N.A., Grimbergen J., Koopman J., Koenderink G.H., Recombinant fibrinogen reveals the differential roles of α- and γ-chain cross-linking and molecular heterogeneity in fibrin clot strain-stiffening, Journal of Thrombosis and Haemostasis, ISSN: 1538-7933, DOI: 10.1111/jth.13650, Vol.15, No.5, pp.938-949, 2017

Abstract:
Essentials Fibrinogen circulates in human plasma as a complex mixture of heterogeneous molecular variants. We measured strain-stiffening of recombinantly produced fibrinogen upon clotting. Factor XIII and molecular heterogeneity alter clot elasticity at the protofibril and fiber level. This highlights the hitherto unknown role of molecular composition in fibrin clot mechanics.

Keywords:
blood coagulation, elasticity, fibrin, polymers, rheology, turbidimetry

(40p.)
7.Graczykowski C., Pawłowski P., Exact physical model of magnetorheological damper, Applied Mathematical Modelling, ISSN: 0307-904X, DOI: 10.1016/j.apm.2017.02.035, Vol.47, pp.400-424, 2017
Graczykowski C., Pawłowski P., Exact physical model of magnetorheological damper, Applied Mathematical Modelling, ISSN: 0307-904X, DOI: 10.1016/j.apm.2017.02.035, Vol.47, pp.400-424, 2017

Abstract:
This paper attempts to fill the gap in the literature by introducing and discussing an enhanced physical model of the MR damper. The essence of the presented model is to combine the effect of compressibility of the MR fluid enclosed in each chamber with the effect of blocking the flow between the chambers in the case of a low pressure difference. As it will be shown, the concurrence of both considered phenomena significantly affects mechanical behaviour of the damper, influences its dissipative characteristics, and in particular, it is the reason behind the distinctive ‘z-shaped’ force–velocity hysteresis loops observed in experiments. The paper presents explanation of the observed phenomena, detailed derivation of the thermodynamic equations governing response of the damper, their implementation for various constitutive models of the magnetorheological fluid and, finally, formulation of the corresponding reduced and parametric models. Experimental validation shows that proper identification of physical parameters of the proposed mathematical model yields the correct shapes of force–velocity hysteresis loops.

Keywords:
Magnetorheological fluid dampers, Smart fluids, Hysteresis modelling

(35p.)
8.Zieliński T.G., Microstructure representations for sound absorbing fibrous media: 3D and 2D multiscale modelling and experiments, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2017.07.047, Vol.409, pp.112-130, 2017
Zieliński T.G., Microstructure representations for sound absorbing fibrous media: 3D and 2D multiscale modelling and experiments, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2017.07.047, Vol.409, pp.112-130, 2017

Abstract:
The paper proposes and investigates computationally-efficient microstructure representations for sound absorbing fibrous media. Three-dimensional volume elements involving non-trivial periodic arrangements of straight fibres are examined as well as simple two-dimensional cells. It has been found that a simple 2D quasi-representative cell can provide similar predictions as a volume element which is in general much more geometrically accurate for typical fibrous materials. The multiscale modelling allowed to determine the effective speeds and damping of acoustic waves propagating in such media, which brings up a discussion on the correlation between the speed, penetration range and attenuation of sound waves. Original experiments on manufactured copper-wire samples are presented and the microstructure-based calculations of acoustic absorption are compared with the corresponding experimental results. In fact, the comparison suggested the microstructure modifications leading to representations with non-uniformly distributed fibres.

Keywords:
sound absorption, fibrous materials, multiscale modelling, microstructure representations

(35p.)
9.Banach Z., Larecki W., Kershaw-type transport equations for fermionic radiation, ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK ZAMP, ISSN: 0044-2275, DOI: 10.1007/s00033-017-0847-z, Vol.68, No.4, pp.100-1-100-24, 2017
Banach Z., Larecki W., Kershaw-type transport equations for fermionic radiation, ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK ZAMP, ISSN: 0044-2275, DOI: 10.1007/s00033-017-0847-z, Vol.68, No.4, pp.100-1-100-24, 2017

Abstract:
Besides the maximum entropy closure procedure, other procedures can be used to close the systems of spectral moment equations. In the case of classical and bosonic radiation, the closed-form analytic Kershaw-type and B-distribution closure procedures have been used. It is shown that the Kershaw-type closure procedure can also be applied to the spectra moment equations of fermionic radiation. First, a description of the Kershaw-type closure for the system consisting of an arbitrary number of one-dimensional moment equations is presented. Next, the Kershaw-type two-field and three-field transport equations for fermionic radiation are analyzed. In the first case, the independent variables are the energy density and the heat flux. The second case includes additionally the flux of the heat flux as an independent variable. The generalization of the former two-field case to three space dimensions is also presented. The fermionic Kershaw-type closures differ from those previously derived for classical and bosonic radiation. It is proved that the obtained one-dimensional systems of transport equations are strictly hyperbolic and causal. The fermionic Kershaw-type closure functions behave qualitatively in the same way as the fermionic maximum entropy closure functions, but attain different numerical values.

Keywords:
Fermionic radiation, Moment equations, Moment realizability problem, Kershaw-type closure, Three-moment transport

(35p.)
10.Jarecki L., Misztal-Faraj B., Non-linear stress-orientation behavior of flexible chain polymers under fast elongational flow, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2017.08.028, Vol.95, pp.368-381, 2017
Jarecki L., Misztal-Faraj B., Non-linear stress-orientation behavior of flexible chain polymers under fast elongational flow, EUROPEAN POLYMER JOURNAL, ISSN: 0014-3057, DOI: 10.1016/j.eurpolymj.2017.08.028, Vol.95, pp.368-381, 2017

Abstract:
Closed-form analytical formulas are proposed for non-linear stress-orientation relation valid in the entire range of tensile stresses, intermediate and high, basing on the inverse Langevin chain statistics. Tensile force and orientation characteristics for single, flexible chain macromolecule are reconsidered in a closed-form Padè approximation of the inverse Langevin function in the entire range of chain extensions, as well as the dynamics of molecular deformation and orientation for systems of chains subjected to uniaxial elongational flow. Average stress and orientation tensors, not collinear in the non-linear range, as well as the tensile stress and axial orientation factor of the chain segments in the system are calculated. For the intermediate tensile stresses, the closed-form formula is derived in the first non-Gaussian term approximation of the inverse Langevin function with the assumption of dominating longitudinal elongation of the chains. The high-stress non-linearity formula is derived with the Padè and Peterlin modulus approximations and aligned chain end-to-end vectors by the flow. Both formulas are validated by exact numerical calculations without the assumptions and influence of the approximations is estimated. Ranges of applicability of the formulas are illustrated and examples of their application are presented.

Keywords:
Molecular orientation, Tensile stress, Non-linear stress-orientation behavior, Elongational flow, Langevin chain statistics

(35p.)
11.Colabella L., Cisilino A.P., Häiat G., Kowalczyk P., Mimetization of the elastic properties of cancellous bone via a parameterized cellular material, Biomechanics and Modeling in Mechanobiology, ISSN: 1617-7959, DOI: 10.1007/s10237-017-0901-y, Vol.16, No.5, pp.1485-1502, 2017
Colabella L., Cisilino A.P., Häiat G., Kowalczyk P., Mimetization of the elastic properties of cancellous bone via a parameterized cellular material, Biomechanics and Modeling in Mechanobiology, ISSN: 1617-7959, DOI: 10.1007/s10237-017-0901-y, Vol.16, No.5, pp.1485-1502, 2017

Abstract:
Bone tissue mechanical properties and trabecular microarchitecture are the main factors that determine the biomechanical properties of cancellous bone. Artificial cancellous microstructures, typically described by a reduced number of geometrical parameters, can be designed to obtain a mechanical behavior mimicking that of natural bone. In this work, we assess the ability of the parameterized microstructure introduced by Kowalczyk (Comput Methods Biomech Biomed Eng 9:135–147, 2006. doi:10.1080/10255840600751473) to mimic the elastic response of cancellous bone. Artificial microstructures are compared with actual bone samples in terms of elasticity matrices and their symmetry classes. The capability of the parameterized microstructure to combine the dominant isotropic, hexagonal, tetragonal and orthorhombic symmetry classes in the proportions present in the cancellous bone is shown. Based on this finding, two optimization approaches are devised to find the geometrical parameters of the artificial microstructure that better mimics the elastic response of a target natural bone specimen: a Sequential Quadratic Programming algorithm that minimizes the norm of the difference between the elasticity matrices, and a Pattern Search algorithm that minimizes the difference between the symmetry class decompositions. The pattern search approach is found to produce the best results. The performance of the method is demonstrated via analyses for 146 bone samples.

Keywords:
Cancellous bone, Parameterized microstructure, Elastic properties, Homogenization, Symmetry classes, Optimization

(35p.)
12.Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Byra M., Nowicki A., Open access database of raw ultrasonic signals acquired from malignant and benign breast lesions, Medical Physics, ISSN: 0094-2405, DOI: 10.1002/mp.12538, Vol.44, No.9, pp.1-5, 2017
Piotrzkowska-Wróblewska H., Dobruch-Sobczak K., Byra M., Nowicki A., Open access database of raw ultrasonic signals acquired from malignant and benign breast lesions, Medical Physics, ISSN: 0094-2405, DOI: 10.1002/mp.12538, Vol.44, No.9, pp.1-5, 2017

Abstract:
Purpose: The aim of this paper is to provide access to a database consisting of the raw radio-frequency ultrasonic echoes acquired from malignant and benign breast lesions. The database is freely
available for study and signal analysis.
Acquisition and validation methods: The ultrasonic radio-frequency echoes were recorded from breast focal lesions of patients of the Institute of Oncology in Warsaw. The data were collected between 11/2013 and 10/2015. Patients were examined by a radiologist with 18 yr’ experience in the ultrasonic examination of breast lesions. The set of data includes scans from 52 malignant and 48 benign breast lesions recorded in a group of 78 women. For each lesion, two individual orthogonal scans from the pathological region were acquired with the Ultrasonix SonixTouch Research ultrasound scanner using the L14-5/38 linear array transducer. All malignant lesions were histologically assessed by core needle biopsy. In the case of benign lesions, part of them was histologically assessed and another part was observed over a 2-year period. Data format and usage notes: The radio-frequency echoes were stored in Matlab file format. For each scan, the region of interest was provided to correctly indicate the lesion area. Moreover, for each lesion, the BI-RADS category and the lesion class were included. Two code examples of data manipulation are presented. The data can be downloaded via the Zenodo repository (https://doi.org/10.5281/zenodo.545928) or the website http ://bluebox.ippt.gov.pl/~hpiotrzk.
Potential applications: The database can be used to test quantitative ultrasound techniques and ultrasound image processing algorithms, or to develop computer-aided diagno sis systems.

Keywords:
breast lesions, dataset, ultrasonic signals, ultrasonography

(35p.)
13.Maździarz M., Mrozek A., Kuś W., Burczyński T., First-principles study of new X-graphene and Y-graphene polymorphs generated by the two stage strategy, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2017.08.066, Vol.202, pp.7-14, 2017
Maździarz M., Mrozek A., Kuś W., Burczyński T., First-principles study of new X-graphene and Y-graphene polymorphs generated by the two stage strategy, MATERIALS CHEMISTRY AND PHYSICS, ISSN: 0254-0584, DOI: 10.1016/j.matchemphys.2017.08.066, Vol.202, pp.7-14, 2017

Abstract:
Two potentially new, 2D-graphene-like materials have been generated by the two stage searching strategy combining molecular and ab initio approach. The two candidates obtained from the evolutionary based algorithm and molecular calculations were then in depth analysed using first-principles Density Functional Theory from the mechanical, structural, phonon and electronic properties point of view. Both proposed polymorphs of graphene (oP8-P2mm) are mechanically and dynamically stable and can be metallic-like.

Keywords:
Carbon; Graphene; Ab initio calculations; Mechanical properties; Elastic properties

(30p.)
14.Pierini F., Lanzi M., Nakielski P., Kowalewski T.A., Electrospun Polyaniline-Based Composite Nanofibers: Tuning the Electrical Conductivity by Tailoring the Structure of Thiol-Protected Metal Nanoparticles, Journal of Nanomaterials, ISSN: 1687-4110, DOI: 10.1155/2017/6142140, Vol.2017, pp.1-10, 2017
Pierini F., Lanzi M., Nakielski P., Kowalewski T.A., Electrospun Polyaniline-Based Composite Nanofibers: Tuning the Electrical Conductivity by Tailoring the Structure of Thiol-Protected Metal Nanoparticles, Journal of Nanomaterials, ISSN: 1687-4110, DOI: 10.1155/2017/6142140, Vol.2017, pp.1-10, 2017

Abstract:
Composite nanofibers made of a polyaniline-based polymer blend and different thiol-capped metal nanoparticles were prepared using ex situ synthesis and electrospinning technique. The effects of the nanoparticle composition and chemical structure on the electrical properties of the nanocomposites were investigated. This study confirmed that Brust’s procedure is an effective method for the synthesis of sub-10 nm silver, gold, and silver-gold alloy nanoparticles protected with different types of thiols. Electron microscopy results demonstrated that electrospinning is a valuable technique for the production of composite nanofibers with similar morphology and revealed that nanofillers are well-dispersed into the polymer matrix. X-ray diffraction tests proved the lack of a significant influence of the nanoparticle chemical structure on the polyaniline chain arrangement. However, the introduction of conductive nanofillers in the polymer matrix influences the charge transport noticeably improving electrical conductivity. The enhancement of electrical properties is mediated by the nanoparticle capping layer structure. The metal nanoparticle core composition is a key parameter, which exerted a significant influence on the conductivity of the nanocomposites. These results prove that the proposed method can be used to tune the electrical properties of nanocomposites.

(30p.)
15.Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Quantized mechanics of affinely-rigid bodies, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.4501, pp.1-19, 2017
Sławianowski J.J., Kovalchuk V., Gołubowska B., Martens A., Rożko E.E., Quantized mechanics of affinely-rigid bodies, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, ISSN: 0170-4214, DOI: 10.1002/mma.4501, pp.1-19, 2017

Abstract:
In this paper, we develop the main ideas of the quantized version of affinely rigid (homogeneously deformable) motion. We base our consideration on the usual Schrödinger formulation of quantum mechanics in the configurationmanifold, which is given, in our case, by the affine group or equivalently by the semi-direct product of the linear group GL(n,R) and the space of translations R^n, where n equals the dimension of the “physical space.” In particular, we discuss the problem of dynamical invariance of the kinetic energy under the action of the whole affine group, not only under the isometry subgroup. Technically, the treatment is based on the 2-polar decomposition of the matrix of the internal configuration and on the Peter-Weyl theory of generalized Fourier series on Lie groups. One can hope that our results may be applied in quantum problems of elastic media and microstructured continua.

Keywords:
Homogeneously deformable body, Peter-Weyl analysis, Schrödinger quantization.

(25p.)
16.Basista M., Jakubowska J., Węglewski W., Processing Induced Flaws in Aluminum–Alumina Interpenetrating Phase Composites, Advanced Engineering Materials, ISSN: 1438-1656, DOI: 10.1002/adem.201700484, pp.1700484-1-1700484-14, 2017
Basista M., Jakubowska J., Węglewski W., Processing Induced Flaws in Aluminum–Alumina Interpenetrating Phase Composites, Advanced Engineering Materials, ISSN: 1438-1656, DOI: 10.1002/adem.201700484, pp.1700484-1-1700484-14, 2017

Abstract:
This review paper deals with flaws in aluminum–alumina composites and FGMs induced by their manufacturing processes. Aluminum–alumina composites have been studied for many years as potentially interesting materials for applications, for example, in the automotive sector due to their enhanced mechanical strength, wear resistance, good heat conductivity and low specific weight. The focus here is on the interpenetrating phase composites (IPCs) manufactured by infiltration of porous alumina preforms with molten aluminum alloys. The primary objective is to provide an updated overview of research findings on a variety of flaws occurring at different stages of the manufacturing processes. Some precautions on how to avoid processing induced flaws in aluminum–alumina bulk composites and FGMs are mentioned.

(25p.)
17.Egner H., Ryś M., Total energy equivalence in constitutive modeling of multidissipative materials, INTERNATIONAL JOURNAL OF DAMAGE MECHANICS, ISSN: 1056-7895, DOI: 10.1177/1056789516679496, Vol.26, No.3, pp.417-446, 2017
Egner H., Ryś M., Total energy equivalence in constitutive modeling of multidissipative materials, INTERNATIONAL JOURNAL OF DAMAGE MECHANICS, ISSN: 1056-7895, DOI: 10.1177/1056789516679496, Vol.26, No.3, pp.417-446, 2017

Abstract:
In the present work, the total energy equivalence hypothesis was applied in constitutive modeling of engineering materials. The approach originally developed for damaged materials, was extended to modeling not only damage but also other dissipative phenomena, like phase transformation, in a consistent manner. The proposed model was examined by means of parametric studies to show its ability to reflect different experimentally observed features of real materials.

Keywords:
Constitutive modeling, dissipative material, plasticity, damage, phase transformation

(25p.)
18.Takeda K., Matsui R., Tobushi H., Pieczyska E.A., Torsional deformation properties of SMA tapes and their application to bias-type reciprocating rotary driving actuator, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.69, No.4-5, pp.289-303, 2017
Takeda K., Matsui R., Tobushi H., Pieczyska E.A., Torsional deformation properties of SMA tapes and their application to bias-type reciprocating rotary driving actuator, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.69, No.4-5, pp.289-303, 2017

Abstract:
In order to develop the reciprocating rotary driving actuator with a simple mechanism using shape memory alloy (SMA) tapes, the graphical method to design the actuator was proposed based on the torsional deformation properties of SMA tapes. The torsional deformation properties of the SME tape showing the shape memory effect (SME) and the SE tape showing superelasticity (SE) were obtained. The bias-type reciprocating rotary actuator was composed of the pretwisted SME tape and the flat SE tape in series. The design chart expressed by the relationship between torque and twisting angle of the SME tape and the SE tape was proposed. The rotational angle and torque, which vary depending on temperature, can be estimated based on the design chart. The rotational angle is controlled by adjusting the mounting angle of the SME tape and the heating temperature. The automatically opening and closing blind driven by sunlight was demonstrated. The blind was controlled by using the reciprocating rotary element composed of the SME tape and the SE tape. The behavior of the blind can be achieved based on the proposed design method of the reciprocating rotary driving element

Keywords:
shape memory alloy, tape, torsion, actuator, reciprocating rotation, design chart, bias-type

(25p.)
19.Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Roszkowska-Purska K., Nowicki A., Jakubowski W., Usefulness of combined BI-RADS analysis and Nakagami statistics of ultrasound echoes in the diagnosis of breast lesions, Clinical Radiology, ISSN: 0009-9260, DOI: 10.1016/j.crad.2016.11.009, Vol.72, pp.339.e7-339.e15, 2017
Dobruch-Sobczak K., Piotrzkowska-Wróblewska H., Roszkowska-Purska K., Nowicki A., Jakubowski W., Usefulness of combined BI-RADS analysis and Nakagami statistics of ultrasound echoes in the diagnosis of breast lesions, Clinical Radiology, ISSN: 0009-9260, DOI: 10.1016/j.crad.2016.11.009, Vol.72, pp.339.e7-339.e15, 2017

Abstract:
AIM: To develop a method combining the statistics of the ultrasound backscatter and the Breast Imaging-Reporting and Data System (BI-RADS) classification to enhance the differentiation of breast tumours.
MATERIALS AND METHODS: The Nakagami shape parameter m was used to characterise the scatter properties of breast tumours. Raw data from the radiofrequency (RF) echo-signal and Bmode images from 107 (32 malignant and 75 benign) lesions and their surrounding tissue were recorded. Three different characteristic values of the shape parameters of m (maximum [mLmax], minimum [mLmin] and average [mLavg]) and differences between m parameters (Dmmax, Dmmin, Dmavg) of the lesions and their surrounding tissues were assessed. A lesion with a BI-RADS score of 3 was considered benign, while a lesion with a score of 4 was considered malignant (a cut-off of BI-RADS 3/4 was set for all patients).
RESULTS: The area under the receiver operating characteristic (ROC) curve (AUC) was equal to 0.966 for BI-RADS, with 100% sensitivity and 54.67% specificity. All malignant lesions were diagnosed correctly, whereas 34 benign lesions were biopsied unnecessarily. In assessing the Nakagami statistics, the sum of the sensitivity and specificity was the best for mLavg (62.5% and 93.33%, respectively). Only four of 20 lesions were found over the cut-off value in BI-RADS of 4a. When comparing the differences in m parameters, Dmavg had the highest sensitivity of 90% (only three of 32 lesions were false negative). These three lesions were classified as BIRADS category 4c. The combined use of B-mode and mLmin parameter improve the AUC up to 0.978 (pĽ0.088), compared to BI-RADS alone.
CONCLUSION: The combination of the parametric imaging and the BI-RADS assessment does not significantly improve the differentiation of breast lesions, but it has the potential to better identify the group of patients with mainly benign lesions that have a low level of suspicion for malignancy with a BI-RADS score of 4a.

(25p.)
20.Bajer C.I., Dyniewicz B., Shillor M., A Gao beam subjected to a moving inertial point load, Mathematics and Mechanics of Solids, ISSN: 1081-2865, DOI: 10.1177/1081286517718229, pp.1-12, 2017
Bajer C.I., Dyniewicz B., Shillor M., A Gao beam subjected to a moving inertial point load, Mathematics and Mechanics of Solids, ISSN: 1081-2865, DOI: 10.1177/1081286517718229, pp.1-12, 2017

Abstract:
A model for the dynamics of a Gao elastic or viscoelastic nonlinear beam that is subject to a horizontally moving vertical point-force is modeled and computationally studied. In particular, the behavior and vibrations of the beam as the mass is moving on it is investigated. Such problems arise naturally in transportation systems with rails. A time-marching finite element numerical algorithm for the problem is developed and implemented. Results of representative simulations are depicted and compared to the behavior of a linear Euler beam with a moving mass.

Keywords:
Gao beam, moving inertial point load, Finite Element simulations, beam vibration

(25p.)
21.Rojek J., Nosewicz S., Chmielewski M., MICRO-MACRO RELATIONSHIPS FROM DISCRETE ELEMENT SIMULATIONS OF SINTERING, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, ISSN: 1543-1649, DOI: 10.1615/IntJMultCompEng.2017020322, Vol.15, No.4, pp.323-342, 2017
Rojek J., Nosewicz S., Chmielewski M., MICRO-MACRO RELATIONSHIPS FROM DISCRETE ELEMENT SIMULATIONS OF SINTERING, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, ISSN: 1543-1649, DOI: 10.1615/IntJMultCompEng.2017020322, Vol.15, No.4, pp.323-342, 2017

Abstract:
A two-scale modeling framework for sintering processes has been presented. Formulation of the micromechanical model of sintering developed in the discrete element method and basic relationships in the macroscopic model of sintering have been briefly reviewed. The methodology to determine macroscopic quantities–stress, strains, and constitutive viscous properties-from the discrete element simulations has been presented. This methodology has been applied to modeling of NiAl sintering. First, the discrete element model (DEM) has been calibrated by fitting the numerical densification curve to the experimental data. The DEM model with calibrated parameters has been used in simulations specially conceived to give macroscopic viscous moduli of the sintered material. Using the averaging procedures macroscopic stresses and strains have been calculated. Strain rates have been obtained differentiating the strain curves with respect to time. Finally, the viscous constitutive properties of the sintered material have been determined. The dependence of the shear and volumetric viscous moduli on the relative density (or equivalently) on the porosity has been obtained. It has been found that the numerical simulations predict a similar dependence as that assumed in the phenomenological macroscopic models. Thus, the validity of the micro-macro relationships obtained from the discrete element simulations of powder sintering has been confirmed. The proposed methodology allows us to use the discrete element model in the framework of multiscale modeling of sintering.

Keywords:
discrete element method, sintering, simulation, micro-macro relationships, multiscale modeling

(25p.)
22.Maździarz M., Rojek J., Nosewicz S., ESTIMATION OF MICROMECHANICAL NiAl SINTERING MODEL PARAMETERS FROM THE MOLECULAR SIMULATIONS, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, ISSN: 1543-1649, DOI: 10.1615/IntJMultCompEng.2017020289 , Vol.15, No.4, pp.343-358, 2017
Maździarz M., Rojek J., Nosewicz S., ESTIMATION OF MICROMECHANICAL NiAl SINTERING MODEL PARAMETERS FROM THE MOLECULAR SIMULATIONS, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, ISSN: 1543-1649, DOI: 10.1615/IntJMultCompEng.2017020289 , Vol.15, No.4, pp.343-358, 2017

Abstract:
Molecular statics/dynamics estimation of constitutive parameters for a micromechanical NiAl sintering model is reported in this paper. The parameters include temperature-dependent diffusion coefficients, surface energy, and linear thermal expansion. These parameters define material behavior during sintering and are used in the sintering particle model implemented in the discrete element model. The investigated material, the NiAl intermetallic, belongs to novel materials characterized by advantageous mechanical properties. Various machine elements are manufactured from a pure NiAl powder or from powder mixtures containing the NiAl using the sintering technology. It is well known that sintering is governed by diffusion. Therefore diffusive properties are important parameters of the micromechanical model of sintering. Numerical estimation of the model parameters by simulations at the lower scale is a powerful tool alternative to experimental methods. Molecular statics and dynamics models for NiAl have been created using the embedded atom model potential. Numerical simulations have allowed us to estimate the volume, surface, and grain-boundary diffusivity for the B2-type NiAl in the 1573 to 1673 K temperature range. Dependence of the diffusion coefficients on temperature has been determined and validity of the Arrhenius-type temperature dependency has been assessed. The parameters evaluated numerically have been compared with available experimental data as well as with theoretical predictions obtained with other methods. Many of the results presented in this paper have a pioneer character and are not known in the literature.

Keywords:
NiAl, sintering, diffusivity, molecular dynamics, molecular statics, nanoparticles

(25p.)
23.Glinicki M.A., Dąbrowski M., Skrzypczyński M., Influence of curing on the properties of air-entrained concrete in the upper layer of exposed aggregate pavement-modelling study, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.XXII/LXXXIV, No.4, pp.271-281, 2017
Glinicki M.A., Dąbrowski M., Skrzypczyński M., Influence of curing on the properties of air-entrained concrete in the upper layer of exposed aggregate pavement-modelling study, CEMENT, WAPNO, BETON, ISSN: 1425-8129, Vol.XXII/LXXXIV, No.4, pp.271-281, 2017

Abstract:
Modelling studies in laboratory of the effect of curing on the mechanical properties and durability of the concrete pavement with exposed aggregate are presented. Air-entrained concrete was designed as the top layer of a motorway pavement with the use of two types of cements: CEM I and CEM III/A. The w/c increase (from 0.34 to 0.37) and change of cement type (CEM I 42.5N and CEM III/A 42.5 N) in properly air-entrained concrete did not influence significantly the internal frost resistance F200 - a decrease of the compressive strength after 200 freeze-thaw cycles was in the range from 4 to 12%. The lowest reduction of strength was observed for concrete with CEM I, w/c=0.34 and proper air entrainment. The properly air-entrained concrete layer with exposed aggregate, which was cured with a curing agent with closure capacity > 85%, was characterized by a very good resistance to surface scaling - the mass of scales m56 was equal to 0.10-0.12 kg/m2, irrespective of the type of cement and w/c ratio. However, there was a significant increase in the water absorption rate, surface scaling and chloride permeability, which caused with inadequate curing

Keywords:
air entrained concrete, curing, durability, exposed aggregate pavement, frost resistance, road pavement, permeability, scaling resistance

(15p.)
24.Levintant Zayonts N., Kwiatkowski L., Swiatek Z., Brzozowska J., Local Pseudoelastic Behaviour and Surface Characteristics of N Ion Implanted NiTi Shape Memory Alloy, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.132.210, Vol.132, No.2, pp.210-216, 2017
Levintant Zayonts N., Kwiatkowski L., Swiatek Z., Brzozowska J., Local Pseudoelastic Behaviour and Surface Characteristics of N Ion Implanted NiTi Shape Memory Alloy, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.132.210, Vol.132, No.2, pp.210-216, 2017

Abstract:
The main goal of the proposed paper is to present the results of the nitrogen ion implantation effects on mechanical and corrosion properties of NiTi shape memory alloy. Local pseudoelasticity phenomena of NiTi were determined using the ultra-low load applied system. The load–penetration depth curves show that lower nitrogen fluence improves mechanical properties in the near surface layer but higher ion fluence leads to degradation of pseudoelasticity properties. Corrosion resistance of NiTi in the Ringer solution was evaluated by means of electrochemical methods. The results of potentiodynamic measurements in the anodic range for implanted NiTi indicate a decrease of passive current density range in comparison with non-treated NiTi, without any signs related to Ni release. The results of impedance measurements recorded at the corrosion potential show a capacitive behaviour for all samples without clear predominance of one of them. It can be explained by the fact that this result concerns the first stage of corrosion exposition. It is shown that nitrogen ion implantation leads to formation of modified surface of improved physicochemical properties

(15p.)
25.Tauzowski P., Lógó J., Pintér E., Parametric Study on the Element Size Effect for Optimal Topologies, Periodica Polytechnica Civil Engineering, ISSN: 0553-6626, DOI: 10.3311/PPci.0000, pp.1-10, 2017(15p.)
26.Ustrzycka A., Mróz Z., Kowalewski Z.L., EXPERIMENTAL ANALYSIS AND MODELLING OF FATIGUE CRACK INITIATION MECHANISMS, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl.55.4.1443, Vol.55, No.4, pp.1443-1448, 2017
Ustrzycka A., Mróz Z., Kowalewski Z.L., EXPERIMENTAL ANALYSIS AND MODELLING OF FATIGUE CRACK INITIATION MECHANISMS, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, DOI: 10.15632/jtam-pl.55.4.1443, Vol.55, No.4, pp.1443-1448, 2017

Abstract:
The present work is devoted to simulation of fatigue crack initiation for cyclic loading within the nominal elastic regime. It is assumed that damage growth occurs due to action of meanstress and its fluctuations induced by crystalline grain inhomogeneity and the free boundary effect. The macrocrack initiation corresponds to a critical value of accumulated damage. The modelling of damage growth is supported by Electronic Speckle Pattern Interferometry (ESPI) apparatus using coherent laser light.

Keywords:
fatigue crack initiation, damage evolution, optical methods

(15p.)
27.Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., PETROGRAPHIC IDENTIFICATION OF REACTIVE MINERALS IN DOMESTIC AGGREGATES AND THEIR CLASSIFICATION ACCORDING TO RILEM AND ASTM RECOMMENDATIONS, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.017.015, Vol.16, pp.223-239, 2017
Jóźwiak-Niedźwiedzka D., Gibas K., Glinicki M.A., PETROGRAPHIC IDENTIFICATION OF REACTIVE MINERALS IN DOMESTIC AGGREGATES AND THEIR CLASSIFICATION ACCORDING TO RILEM AND ASTM RECOMMENDATIONS, Roads and Bridges - Drogi i Mosty, ISSN: 1643-1618, DOI: 10.7409/rabdim.017.015, Vol.16, pp.223-239, 2017

Abstract:
Considering the long-time durability of concrete in road infrastructure it is important to control the threat of expansive reaction between sodium and potassium hydroxides in the pore solution and the reactive minerals present in the aggregate. Petrographic analysis is the basis for the qualification of aggregates to appropriate classes of reactivity according to ASTM C1778 and RILEM recommendations. This paper presents the results of petrographic analyses of thin sections made from twenty different domestic aggregates. The tested crushed aggregates were obtained from bedrock and glacial deposits. The evaluation of the mineral composition of aggregates included identification of deleterious components and determination of the content of reactive forms of silica. This enabled preliminary classification of aggregate in one of the three classes of reactivity according to RILEM. Obtained results provide an initial assessment of potential reactivity of aggregates and can assist in making decisions to undertake further accelerated or long-term laboratory testing or to modify the concrete mix design.

Keywords:
aggregate, alkali-aggregate reaction (AAR), petrographic analysis, reactive minerals, thin sections

(11p.)
28.Widłaszewski J., Nowak M., Nowak Z., Kurp P., Laser-assisted forming of thin-walled profiles, Metal Forming, ISSN: 0867-2628, Vol.XXVIII, No.3, pp.183-198, 2017
Widłaszewski J., Nowak M., Nowak Z., Kurp P., Laser-assisted forming of thin-walled profiles, Metal Forming, ISSN: 0867-2628, Vol.XXVIII, No.3, pp.183-198, 2017

Abstract:
Forming processes assisted by localised laser heating are studied in recent years. Heating is used to make it possible or facilitate forming of materials, which exhibit such adverse properties as: brittleness, effects of high work-hardening or a high elastic springback. The hereby presented investigations concern the hybrid thermo-mechanical forming of thin-walled parts using local heating of the material by the laser beam. The research is aimed at forming of parts from materials used in the aviation industry, such as the nickel-base super-alloys Inconel 625, Inconel 718, and also martensitic superalloys AISI 410 and AISI 325. Preliminary investigations are conducted using X5CrNil8-10 (1.4301) stainless steel. Experimental study and numerical simulations cover the behaviour of thin beams 1 mm thick, subjected to mechanical load in the cantilever arrangement and heated by the CO2 laser beam moving from the free end of the sample towards its fixture. The possibility of obtaining large bending deformations relatively easily due to the application of laser beam is demonstrated experimentally. Experimentally verified finite element numerical simulations show the intense plastic flow of the material layer heated by the laser beam. It is accompanied by a shift of the cross-section neutral axis of the beam. Bending of thin-walled tubes in a specially designed device is studied in the next step. It allows introducing mechanical loading in a controlled manner, heating the material by a moving laser beam and forcing the required deformation according to the kinematic scheme of the device.

Keywords:
laser-assisted forming, finite element method, thin-walled structure

(10p.)
29.Fantilli A.P., Jóźwiak-Niedźwiedzka D., Gibas K., Dulnik J., The compability between wool fibers and cementitious mortars, ICBBM & EcoGRAFI, Second International RILEM Conference on Bio-based Building Materials 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials, 2017-06-21/06-23, Clermont-Ferrand (FR), pp.42-47, 2017
Fantilli A.P., Jóźwiak-Niedźwiedzka D., Gibas K., Dulnik J., The compability between wool fibers and cementitious mortars, ICBBM & EcoGRAFI, Second International RILEM Conference on Bio-based Building Materials 1st Conference on ECOlogical valorisation of GRAnular and FIbrous materials, 2017-06-21/06-23, Clermont-Ferrand (FR), pp.42-47, 2017

Abstract:
The addition of natural fibers residue in cement based materials can be a sustainable technological alternative for traditional dispersed reinforcement, and can improve the performance of brittle matrix materials. The presence of a wool reinforcement can increase the fracture toughness and, at the same time, can reduce the environmental impact of cementitious mortars. The beneficial effects are similarly to those observed in presence of vegetal fibers (e.g., hemp), which have been largely investigated in the literature. However, there are some limits in the use of wool fibers due to their chemical compatibility with the cement matrix, as they can dissolve in alkaline environments. In the present paper, to investigate the compatibility between wool fibers and cementitious mortars, laboratory prototypes have been taken into consideration. Three series of wool-reinforced mortar beams have been cast and cured in water (20°C) or in dry conditions (temp. 20 °C, 50% R.H.) for some days. Portland-limestone cement CEM II has been used, whereas the content of fibers has been limited to about 1% in volume to maintain the workability of the mortars. To investigate the chemical compatibility, and the subsequent effects on the mechanical performances, prototypes have been tested in three point bending. After the mechanical test, the mortars microstructure was evaluated through SEM images and by thin section in transmitted light, in order to individuate a possible relationship between the dissolution of wool and curing conditions. The microstructure observation revealed the capability of wool fibers to bridge the cracks, and to reduce the brittleness of plain mortars. The differences in the mortars microstructure due to alternative curing conditions were also observed and described in the paper. Accordingly, wool could be effectively used to reduce the plastic shrinkage of cementbased composites, like the industrially manufactured polypropylene fibers.

Keywords:
Wool fibers, Plain cement-based mortar, Fiber-reinforced mortar, Polypropylene fibers, Three point bending tests, SEM analyses

30.Pieczyska E.A., Golasiński K., Staszczak M., Maj M., Furuta T., Kuramoto S., A thermomechanical analysis of high elasto-plastic properties of gum metal at various strain rates, M2D, 7th International Conference on Mechanics and Materials in Design, 2017-06-11/06-15, Albufeira (PT), No.7002, pp.131-132, 2017
Pieczyska E.A., Golasiński K., Staszczak M., Maj M., Furuta T., Kuramoto S., A thermomechanical analysis of high elasto-plastic properties of gum metal at various strain rates, M2D, 7th International Conference on Mechanics and Materials in Design, 2017-06-11/06-15, Albufeira (PT), No.7002, pp.131-132, 2017

Abstract:
Mechanical characteristics obtained by MTS testing machine and digital image correlation (DIC) algorithm as well as the related temperature changes in a new B-Ti alloy - Gum Metal, subjected to tension in a wide spectrum of the strain rates, are presented The fast and sensitive infrared camera ThermaCam Phoenix allowed estimating temperature changes accompanying the specimen deformation process in contactless manner. The obtained mechanical curves confirm an ultra-low elastic modulus and high strength of Gum Metal. Furthermore, it was presented how the stress-strain characteristics change from hardening to softening depending on the strain rate. The thermoelastic effect, estimated by the IR technique was discussed according to the Gum Metal yield point.

Keywords:
gum metal, titanium alloy, tension test, strain rate, thermomechanical coupling

31.Maździarz M., Rojek J., Nosewicz S., Estimation of micromechanical NiAl sintering model parameters from the Atomistic Simulations, VII International Conference on Coupled Problems in Science and Engineering, 2017-06-12/06-14, Rhodes Island (GR), pp.1-1, 2017
32.Maździarz M., Rojek J., Nosewicz S., Molecular dynamics study of self-diffusion in stoichiometric B2-NiAl, CMN2017, Congress on Numerical Methods in Engineering, 2017-07-03/07-05, Valencia (ES), pp.1373-1373, 2017
33.Dunić V., Slavković R., Pieczyska E., Thermo-mechanical numerical analysis of transformation-induced stress relaxation during pseudoelastic behavior of SMA, SEECCM, 4th South-East European Conference on Computational Mechanics, 2017-07-03/07-05, Kragujevac (XS), No.T.4.7, pp.28-1-28-6, 2017
Dunić V., Slavković R., Pieczyska E., Thermo-mechanical numerical analysis of transformation-induced stress relaxation during pseudoelastic behavior of SMA, SEECCM, 4th South-East European Conference on Computational Mechanics, 2017-07-03/07-05, Kragujevac (XS), No.T.4.7, pp.28-1-28-6, 2017

Abstract:
A stress relaxation phenomenon is observed by coupled thermo-mechanical numerical analysis of SMA subjected to uniaxial test. The thermo-mechanical coupling is realized in the partitioned approach. The software components for the structural analysis (PAKS) and the heat transfer (PAKT) based on the Finite Element Method (FEM) have been used. The latent heat production is correlated with the amount of the martensitic volume fraction. The thermo-mechanical numerical analysis of a belt type specimen has been investigated for the strain controlled loading with the break during the martensitic transformation. The thermally induced martensitic transformation induced the significant stress change during the loading break what was expected according to the experimental results from literature.

Keywords:
shape memory alloys, stress relaxation, thermo-mechanical coupling, phase transformation, partitioned coupling

34.Hron J., Miloš V., Průša V., Souček O., Tůma K., On thermodynamics of incompressible viscoelastic rate type fluids with temperature dependent material coefficients, INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, ISSN: 0020-7462, DOI: 10.1016/j.ijnonlinmec.2017.06.011, Vol.95, pp.193-208, 2017
Hron J., Miloš V., Průša V., Souček O., Tůma K., On thermodynamics of incompressible viscoelastic rate type fluids with temperature dependent material coefficients, INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, ISSN: 0020-7462, DOI: 10.1016/j.ijnonlinmec.2017.06.011, Vol.95, pp.193-208, 2017

Abstract:
We derive a class of thermodynamically consistent variants of Maxwell/Oldroyd-B type models for incompressible viscoelastic fluids. In particular, we study the models that allow one to consider temperature dependent material coefficients. This naturally calls for the formulation of a temperature evolution equation that would accompany the evolution equations for the mechanical quantities. The evolution equation for the temperature is explicitly formulated, and it is shown to be consistent with the laws of thermodynamics and the evolution equations for the mechanical quantities. The temperature evolution equation contains terms that are ignored or even not thought of in most of the practically oriented (computational) works dealing with this class of fluids. The impact of the additional terms in the temperature evolution equation on the flow dynamics is documented by the solution of simple initial/boundary value problems.

Keywords:
Maxwell fluid; Oldroyd-B fluid; Temperature dependent material coefficients; Thermodynamics; Cylindrical Couette flow; Biaxial extension; Numerical simulations

35.Wasilewski M., Pisarski D., Adaptive optimal control algorithm for vibrational systems under nonlinear friction, MMAR 2017, 22nd International Conference on Methods and Models in Automation and Robotics, 2017-08-28/08-31, Międzyzdroje (PL), pp.107-112, 2017
Wasilewski M., Pisarski D., Adaptive optimal control algorithm for vibrational systems under nonlinear friction, MMAR 2017, 22nd International Conference on Methods and Models in Automation and Robotics, 2017-08-28/08-31, Międzyzdroje (PL), pp.107-112, 2017

Abstract:
In this paper, a novel control algorithm for vibration attenuation is presented. The proposed scheme is developed to control linear systems with a presence of an external disturbance. The goal of the control is to steer the system to prescribed reference trajectory by minimizing associated quadratic performance index.
The synthesis of the control law consists of two steps. At the first step, past measures of disturbance are used to develop a local linear approximation of dynamics of the disturbance signal. Weights of the associated auto-regressive model are calculated by the least-square algorithm. At the second step, the calculated model is used to obtain a linear time-invariant approximation of the control system. The receding horizon control law is then calculated by using finite horizon Linear Quadratic Regulator. The algorithm is verified numerically for a torsional vibrating system under nonlinear, time-varying friction. The results of the simulation are compared to a standard Linear Quadratic Gaussian control.

36.Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., New efficient adaptive control of torsional vibrations induced by sudden nonlinear disturbances, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017
Wasilewski M., Pisarski D., Konowrocki R., Bajer C.I., New efficient adaptive control of torsional vibrations induced by sudden nonlinear disturbances, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), pp.1-2, 2017

Abstract:
The aim of this paper is to present a novel adaptive technique of control of the vibrating drilling systems. The algorithm constitutes an adaptive linear quadratic regulator that uses direct measurements of the disturbance to synthesize its linear dynamic approximation. This approach allows generating control law that includes the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The effectiveness of the algorithm is validated via comprehensive numerical simulations of the control of the simplified drilling model. The results are compared to these obtained with the use of the Linear Quadratic Gaussian regulator.

Keywords:
vibration control, drillstring, adaptive control, auto-regressive model

37.Lumelskyj D., Rojek J., Banabic D., Lazarescu L., Detection of Strain Localization in Nakazima Formability Test - Experimental Research and Numerical Simulation, SHEMET17, 17th International Conference on Sheet Metal, 2017-04-10/04-12, Palermo (IT), DOI: 10.1016/j.proeng.2017.04.016, No.183, pp.89-94, 2017
Lumelskyj D., Rojek J., Banabic D., Lazarescu L., Detection of Strain Localization in Nakazima Formability Test - Experimental Research and Numerical Simulation, SHEMET17, 17th International Conference on Sheet Metal, 2017-04-10/04-12, Palermo (IT), DOI: 10.1016/j.proeng.2017.04.016, No.183, pp.89-94, 2017

Abstract:
This paper presents the investigation on detection of strain localization in experimental research and numerical simulation of sheet metal forming. Experimental tests and numerical simulations of the Nakazima test have been performed for the DC04 grade steel sheet. The onset of localized necking has been determined using the criterion based on analysis of the major principal strain and its first and second time derivatives in the most strained zone. The strain localization has been evaluated by the maximum of strain acceleration which corresponds to the inflection point of the strain velocity vs. time. The limit strains have been calculated numerically and experimentally for specimens undergoing deformation at different strain paths. It has been shown that the numerical model predicts formability limits close to the experimental results. Analyzed criterion can be used as a potential alternative tool to determine formability in standard finite element simulations of sheet forming processes.

Keywords:
sheet forming, formability, forming limit curve, numerical simulation

38.Jurczak G., Maździarz M., Dłużewski P., Finite element modelling of threading dislocation effect on GaN/AlN quantum dot, ICMM5, 5th International Conference on Material Modeling, 2017-06-14/06-16, Rome (IT), pp.1-1, 2017
Jurczak G., Maździarz M., Dłużewski P., Finite element modelling of threading dislocation effect on GaN/AlN quantum dot, ICMM5, 5th International Conference on Material Modeling, 2017-06-14/06-16, Rome (IT), pp.1-1, 2017

Keywords:
Quantum dot, Threading dislocation, Piezoelectricity, Finite element modelling

39.Leyva-Mendivil M.F., Lengiewicz J., Page A., Bressloff N.W., Limbert G., Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study, BIOTRIBOLOGY, ISSN: 2352-5738, DOI: 10.1016/j.biotri.2017.04.001, Vol.11, pp.110-123, 2017
Leyva-Mendivil M.F., Lengiewicz J., Page A., Bressloff N.W., Limbert G., Implications of Multi-asperity Contact for Shear Stress Distribution in the Viable Epidermis – An Image-based Finite Element Study, BIOTRIBOLOGY, ISSN: 2352-5738, DOI: 10.1016/j.biotri.2017.04.001, Vol.11, pp.110-123, 2017

Abstract:
Understanding load transfer mechanisms from the surface of the skin to its deeper layers is crucial in gaining a fundamental insight into damage phenomena related to skin tears, blisters and superficial/deep tissue ulcers. It is unknown how shear stresses in the viable epidermis are conditioned by the skin surface topography and internal microstructure and to which extent their propagation is conditioned by the size of a contacting asperities. In this computational study, these questions were addressed by conducting a series of contact finite element analyses simulating normal indentation of an anatomically-based two-dimensional multi-layer model of the skin by rigid indenters of various sizes and sliding of these indenters over the skin surface. Indentation depths, local (i.e. microscopic) coefficients of friction and Young's modulus of the stratum corneum were also varied. For comparison purpose and for isolating effects arising purely from the skin microstructure, a geometrically-idealised equivalent multi-layer model of the skin was also considered. The multi-asperity contact induced by the skin topographic features in combination with a non-idealised geometry of the skin layers lead to levels of shear stresses much higher than those produced in the geometrically-idealised case. These effects are also modulated by other system parameters (e.g. local coefficient of friction, indenter radius). These findings have major implications for the design and analyses of finite element studies aiming at modelling the tribology of skin, particularly if the focus is on how surface shear stress leads to damage initiation which is a process known to occur across several length scales.

Keywords:
Skin, Microstructure, Contact mechanics, Indentation, Sliding contact, Finite element, Image-based modelling, Material properties

40.Pisarski D., Myśliński A., Online adaptive semi-active vibration damping of slender structures subject to moving loads, ICOEV2017, International Conference on Engineering Vibration, 2017-09-04/09-07, Sofia (BG), pp.1-1, 2017
Pisarski D., Myśliński A., Online adaptive semi-active vibration damping of slender structures subject to moving loads, ICOEV2017, International Conference on Engineering Vibration, 2017-09-04/09-07, Sofia (BG), pp.1-1, 2017

Abstract:
In this paper, the problem of the optimal control of a structure subjected to a moving load has been studied. In contrast to the previous works of the authors, focused on open-loop strategies, this paper has been devoted to an adaptive closed-loop control, where the switched damping strategy is subject to real-time adaptation according to the measured speed of the moving load.
The proposed adaptive controller has been designed based on the use of the reference optimal solutions computed for a given constant velocity and a set of functions describing the sensitivity of the system dynamics to a change in the speed and the initial state. All these data are pre-computed offline and stored in the controller's memory. As a result, the online computational algorithm, based on a simple gradient descent loop, uses a minimal calculation effort. This allows almost immediate updating of the optimal controls, even with the use of a standard PC. The method has been validated by means of numerical experiments carried out for a wide range of the velocity perturbation scenarios. The proposed scheme is general for a class of time-varying bilinear control systems and can be implemented to a wide range of problems concerned with smart structural elements.

41.Mackiewicz S., PODSTAWOWE ZASADY PRZEPROWADZANIA EKSPOZYCJI RADIOGRAFICZNYCH NA PANELACH PŁASKICH, Stary Młyn 2017, KRAJOWA KONFERENCJA BADAŃ RADIOGRAFICZNYCH, 2017-09-04/09-06, Bolesławiec k/Wieruszowa (PL), pp.15-26, 2017
42.Mackiewicz S., Detektory promieniowania stosowane w cyfrowej radiografii bezpośredniej, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, Vol.1-2, pp.44-51, 2017
Mackiewicz S., Detektory promieniowania stosowane w cyfrowej radiografii bezpośredniej, BADANIA NIENISZCZĄCE I DIAGNOSTYKA, ISSN: 2451-4462, Vol.1-2, pp.44-51, 2017

Abstract:
W artykule opisano podstawy działania detektorów promieniowania stosowanych w cyfrowej radiografii bezpośredniej - DR . Scharakteryzowano rożne rodzaje paneli płaskich pod kątem ich przydatności w obszarze badań nieniszczących. W sposób bardziej szczegółowy omówiono panele płaskie z przemianą pośrednią oparte na matrycy a-Si z tranzystorami TFT, które wykazują obecnie największą przydatność do zastosowań w badaniach nieniszczących. Przeanalizowano najważniejsze parametry paneli płaskich w aspekcie ich zastosowań do badań złączy spawanych oraz innych wyrobów i elementów badanych dotychczas tradycyjną metodą radiograficzną

Keywords:
radiografia cyfrowa, panele płaskie, radiografia bezpośrednia DR

43.Pisarski D., Szmidt T., Semi-Active Stabilization of Pipe Discharging Air With Electromagnetic Devices of Motional Type, ICAST2017, The 28th International Conference on Adaptive Structures and Technologies, 2017-10-08/10-11, Kraków (PL), pp.1-1, 2017
Pisarski D., Szmidt T., Semi-Active Stabilization of Pipe Discharging Air With Electromagnetic Devices of Motional Type, ICAST2017, The 28th International Conference on Adaptive Structures and Technologies, 2017-10-08/10-11, Kraków (PL), pp.1-1, 2017

Abstract:
The study deals with a problem of applying electromagnetic devices of motional type to improve the dynamic stability of a pipe conveying air. When the flow velocity reaches its critical value the steady equilibrium position becomes unstable, and self-excited lateral vibrations arise. Electromagnetic devices of another – transformer – type demonstrated to have been highly effective in the passive stabilization of such system as well as active stabilization of similar non-conservative system with a follower force. In the present work, we apply a pair of motional devices made of a conducting plate which is attached to the pipe and moves together with it within the perpendicular magnetic field generated by the controlled electromagnets. This motion generates eddy currents in the plates and a drag force of a viscous character. Under this setting, we firstly investigate the possibility of designing a stabilizing control within the magnetic field’s region where every passive solution results in an unstable or conservative state. For that purpose, we constitute a practical condition justifying the existence of a stabilizing control for a given set of system parameters. Later we pose and solve an optimal control problem aiming at stabilizing the system with the optimal rates of decrease of the system’s energy. The solution is examined by means of numerical simulations performed within the three regions of the flow velocity: low subcritical where the Coriolis acceleration of the conveyed fluid generates the predominate damping force, high subcritical where the inertia of the fluid begins to dominate dynamics of the system, and low supercritical where unstable flutter vibrations start to arise. The effectiveness of the designed optimal controller is validated by comparisons with the corresponding passive solutions.

44.Długosz A., Pokorska I., Glinicki M.A., Jaskulski R., Identification of thermal properties of hardening concrete by means of evolutionary algorithms, ECCOMAS - IPM 2017, 4th International Conference on Inverse Problems in Mechanics of Structures and Materials, 2017-05-31/06-02, Rzeszów - Krasiczyn (PL), pp.17-18, 2017
45.Kurtis K.E., Xi Y., Glinicki M.A., Provis J., Giannini E.R., Fu T., Can We Design Concrete to Survive Nuclear Environments?, CONCRETE INTERNATIONAL, ISSN: 0162-4075, Vol.39, No.11, pp.53-59, 2017
46.Nowak Z., Nowak M., Widłaszewski J., Kurp P., Experimental and numerical investigation on laser-assisted bending of pre-loaded metal plate, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), No.MS13, pp.37-38, 2017
Nowak Z., Nowak M., Widłaszewski J., Kurp P., Experimental and numerical investigation on laser-assisted bending of pre-loaded metal plate, CMM-2017, 22nd International Conference on Computer Methods in Mechanics, 2017-09-13/09-16, Lublin (PL), No.MS13, pp.37-38, 2017

Abstract:
The laser forming technique has an important disadvantage, which is the limitation of plastic deformation generated by a single laser beam pass. In order to increase the plastic deformation one has to repeat the process several times or use the alternative method. To increase the plastic deformation it is possible to add external forces during the laser forming process. In this paper, we investigate the influence of external pre-loads on the laser bending of steel plate. The pre-loads investigated generate bending towards the laser beam. The thermal, elastic-plastic analysis is performed using the commercial nonlinear finite element analysis package ABAQUS. The focus of the paper is to identify how this pattern of the pre-load influence the final bend angle of the plate.

Keywords:
laser forming, force-assisted laser bending, thermo-mechanical simulations, FEA

47.Roszkiewicz A., Nasalski W., Transmission and reflection properties of two-dimensional finite metal crystals, THE EUROPEAN PHYSICAL JOURNAL D, ISSN: 1434-6060, DOI: 10.1140/epjd/e2017-70706-9, Vol.71, No.182, pp.1-12, 2017
Roszkiewicz A., Nasalski W., Transmission and reflection properties of two-dimensional finite metal crystals, THE EUROPEAN PHYSICAL JOURNAL D, ISSN: 1434-6060, DOI: 10.1140/epjd/e2017-70706-9, Vol.71, No.182, pp.1-12, 2017

Abstract:
Optical characteristics of a finite two-dimensional silver stripe photonic crystal of a square lattice are numerically analysed with use of multilayer Rigorous Coupled Wave Analysis. Qualitative changes in optical response of the crystal originated from modifications of the thickness and filling factors of each layer and the polarization direction of the incident wave are shown. The crystal manifests its various characteristics in wideband or narrowband reflection and transmission, while absorption remains low. The behaviour of the crystal is determined by its structure geometry yielding excitation of localized plasmons and collective modes together with interactions between them. The optical response of the square lattice structure is also compared with the response of a triangular lattice crystal.

48.Piechocka I.K., Jansen K.A., Broedersz C.P., Kurniawan N.A., MacKintosh F.C., Koenderink G.H., Multi-scale strain-stiffening of semiflexible bundle networks, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c5sm01992c, Vol.12, No.7, pp.2145-2156, 2016
Piechocka I.K., Jansen K.A., Broedersz C.P., Kurniawan N.A., MacKintosh F.C., Koenderink G.H., Multi-scale strain-stiffening of semiflexible bundle networks, SOFT MATTER, ISSN: 1744-683X, DOI: 10.1039/c5sm01992c, Vol.12, No.7, pp.2145-2156, 2016

Abstract:
Bundles of polymer filaments are responsible for the rich and unique mechanical behaviors of many biomaterials, including cells and extracellular matrices. In fibrin biopolymers, whose nonlinear elastic properties are crucial for normal blood clotting, protofibrils self-assemble and bundle to form networks of semiflexible fibers. Here we show that the extraordinary strain-stiffening response of fibrin networks is a direct reflection of the hierarchical architecture of the fibrin fibers. We measure the rheology of networks of unbundled protofibrils and find excellent agreement with an affine model of extensible wormlike polymers. By direct comparison with these data, we show that physiological fibrin networks composed of thick fibers can be modeled as networks of tight protofibril bundles. We demonstrate that the tightness of coupling between protofibrils in the fibers can be tuned by the degree of enzymatic intermolecular crosslinking by the coagulation factor XIII. Furthermore, at high stress, the protofibrils contribute independently to the network elasticity, which may reflect a decoupling of the tight bundle structure. The hierarchical architecture of fibrin fibers can thus account for the nonlinearity and enormous elastic resilience characteristic of blood clots.

(40p.)
49.Jansen K.A., Bacabac R.G., Piechocka I.K., Koenderink G.H., Cells actively stiffen fibrin networks by generating contractile stress, BIOPHYSICAL JOURNAL, ISSN: 0006-3495, DOI: 10.1016/j.bpj.2013.10.008, Vol.105, No.10, pp.2240-2251, 2013
Jansen K.A., Bacabac R.G., Piechocka I.K., Koenderink G.H., Cells actively stiffen fibrin networks by generating contractile stress, BIOPHYSICAL JOURNAL, ISSN: 0006-3495, DOI: 10.1016/j.bpj.2013.10.008, Vol.105, No.10, pp.2240-2251, 2013

Abstract:
During wound healing and angiogenesis, fibrin serves as a provisional extracellular matrix. We use a model system of fibroblasts embedded in fibrin gels to study how cell-mediated contraction may influence the macroscopic mechanical properties of their extracellular matrix during such processes. We demonstrate by macroscopic shear rheology that the cells increase the elastic modulus of the fibrin gels. Microscopy observations show that this stiffening sets in when the cells spread and apply traction forces on the fibrin fibers. We further show that the stiffening response mimics the effect of an external stress applied by mechanical shear. We propose that stiffening is a consequence of active myosin-driven cell contraction, which provokes a nonlinear elastic response of the fibrin matrix. Cell-induced stiffening is limited to a factor 3 even though fibrin gels can in principle stiffen much more before breaking. We discuss this observation in light of recent models of fibrin gel elasticity, and conclude that the fibroblasts pull out floppy modes, such as thermal bending undulations, from the fibrin network, but do not axially stretch the fibers. Our findings are relevant for understanding the role of matrix contraction by cells during wound healing and cancer development, and may provide design parameters for materials to guide morphogenesis in tissue engineering.

(35p.)
50.Piechocka I.K., van Oosten A.S.G., Breuls R.G., Koenderink G.H., Rheology of Heterotypic Collagen Networks, BIOMACROMOLECULES, ISSN: 1525-7797, DOI: 10.1021/bm200553x, Vol.12, No.7, pp.2797-2805, 2011
Piechocka I.K., van Oosten A.S.G., Breuls R.G., Koenderink G.H., Rheology of Heterotypic Collagen Networks, BIOMACROMOLECULES, ISSN: 1525-7797, DOI: 10.1021/bm200553x, Vol.12, No.7, pp.2797-2805, 2011

Abstract:
Collagen fibrils are the main structural element of connective tissues. In many tissues, these fibrils contain two fibrillar collagens (types I and V) in a ratio that changes during tissue development, regeneration, and various diseases. Here we investigate the influence of collagen composition on the structure and rheology of networks of purified collagen I and V, combining fluorescence and atomic force microscopy, turbidimetry, and rheometry. We demonstrate that the network stiffness strongly decreases with increasing collagen V content, even though the network structure does not substantially change. We compare the rheological data with theoretical models for rigid polymers and find that the elasticity is dominated by nonaffine deformations. There is no analytical theory describing this regime, hampering a quantitative interpretation of the influence of collagen V. Our findings are relevant for understanding molecular origins of tissue biomechanics and for guiding rational design of collagenous biomaterials for biomedical applications.

(40p.)
51.Piechocka I.K., Bacabac R.G., Potters M., MacKintosh F.C., Koenderink G.H., Structural Hierarchy Governs Fibrin Gel Mechanics, BIOPHYSICAL JOURNAL, ISSN: 0006-3495, DOI: 10.1016/j.bpj.2010.01.040, Vol.98, No.10, pp.2281-2289, 2010
Piechocka I.K., Bacabac R.G., Potters M., MacKintosh F.C., Koenderink G.H., Structural Hierarchy Governs Fibrin Gel Mechanics, BIOPHYSICAL JOURNAL, ISSN: 0006-3495, DOI: 10.1016/j.bpj.2010.01.040, Vol.98, No.10, pp.2281-2289, 2010

Abstract:
Fibrin gels are responsible for the mechanical strength of blood clots, which are among the most resilient protein materials in nature. Here we investigate the physical origin of this mechanical behavior by performing rheology measurements on reconstituted fibrin gels. We find that increasing levels of shear strain induce a succession of distinct elastic responses that reflect stretching processes on different length scales. We present a theoretical model that explains these observations in terms of the unique hierarchical architecture of the fibers. The fibers are bundles of semiflexible protofibrils that are loosely connected by flexible linker chains. This architecture makes the fibers 100-fold more flexible to bending than anticipated based on their large diameter. Moreover, in contrast with other biopolymers, fibrin fibers intrinsically stiffen when stretched. The resulting hierarchy of elastic regimes explains the incredible resilience of fibrin clots against large deformations.

(32p.)
52.Meissner M., The influence of acoustic nonlinearity on absorption properties of Helmholtz resonators. Part I: theory, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.24, No.2, pp.179-190, 1999
Meissner M., The influence of acoustic nonlinearity on absorption properties of Helmholtz resonators. Part I: theory, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, Vol.24, No.2, pp.179-190, 1999

Abstract:
This is the first of two companion papers concerned with the nonlinear absorption of Helmholtz resonators at a high amplitude incident wave. The phenomenon has been examined theoretically by use of a model of the acoustic field in the neighborhood of the resonator placed at the end of cylindrical tube. The calculation results have shown that the peak of the absorption coe±cient occurs when the nonlinear resistance is equal to the radiation resistance of the resonator. The full experimental investigations of this phenomenon and a comparison between theoretical and experimental data will be presented in the companion paper (Part II).