Michał Kursa, Ph.D., Eng.

Department of Mechanics of Materials (ZMM)
Division of Micromechanics of Materials (PMM)
position: assistant professor
telephone: (+48) 22 826 12 81 ext.: 304
room: 134
e-mail: mkursa

Doctoral thesis
2010-11-25Modelowanie deformacji plastycznych w kryształach metali metodą przyrostowej minimalizacji energii 
supervisor -- Prof. Henryk Petryk, Ph.D., Dr. Habil., Eng., IPPT PAN
637
 
Recent publications
1.Majewski M., Kursa M., Hołobut P., Kowalczyk-Gajewska K., Micromechanical and numerical analysis of packing and size effects in elastic particulate composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2017.05.004, Vol.124, pp.158-174, 2017
Majewski M., Kursa M., Hołobut P., Kowalczyk-Gajewska K., Micromechanical and numerical analysis of packing and size effects in elastic particulate composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2017.05.004, Vol.124, pp.158-174, 2017

Abstract:
Effects of particle packing and size on the overall elastic properties of particulate random composites are analyzed. In order to account for the two effects the mean-field Morphologically Representative Pattern (MRP) approach is employed and an additional interphase surrounding inclusions (coating) is introduced. The analytical mean-field estimates are compared with the results of computational homogenization performed using the finite element (FE) method. Periodic unit cells with cubic crystal-type arrangements and representative volume elements with random distributions of particles are used for verification purposes. The validity of the MRP estimates with respect to the FE results is assessed.

Keywords:
Composite materials, Elasticity, Micro-mechanics, Packing and size effects

2.Lengiewicz J., Kursa M., Hołobut P., Modular-robotic structures for scalable collective actuation, ROBOTICA, ISSN: 0263-5747, DOI: 10.1017/S026357471500082X, Vol.35, No.4, pp.787-808, 2017
Lengiewicz J., Kursa M., Hołobut P., Modular-robotic structures for scalable collective actuation, ROBOTICA, ISSN: 0263-5747, DOI: 10.1017/S026357471500082X, Vol.35, No.4, pp.787-808, 2017

Abstract:
We propose a new class of modular-robotic structures, intended to produce forces which scale with the number of modules. We adopt the concept of a spherical catom and extend it by a new connection type which is relatively strong but static. We examine analytically and numerically the mechanical properties of two collective-actuator designs. The simulations are based on the discrete element method (DEM), with friction and elastic deformations taken into account. One of the actuators is shown to generate forces proportional to its volume. This property seems necessary for building modular structures of useful strength and dimensions.

Keywords:
Modular robots, Self-reconfiguration, Programmable matter, Actuators, Mechanical strength

3.Petryk H., Kursa M., Incremental work minimization algorithm for rate-independent plasticity of single crystals, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, ISSN: 0029-5981, DOI: 10.1002/nme.4925, Vol.104, No.3, pp.157-184, 2015
Petryk H., Kursa M., Incremental work minimization algorithm for rate-independent plasticity of single crystals, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, ISSN: 0029-5981, DOI: 10.1002/nme.4925, Vol.104, No.3, pp.157-184, 2015

Abstract:
A new constitutive algorithm for the rate-independent crystal plasticity is presented. It is based on asymptotically exact formulation of the set of constitutive equations and inequalities as a minimum problem for the incremental work expressed by a quadratic function of non-negative crystallographic slips. This approach requires selective symmetrization of the slip-system interaction matrix restricted to active slip-systems, while the latent hardening rule for inactive slip-systems is arbitrary. The active slip-system set and incremental slips are determined by finding a constrained minimum point of the incremental work. The solutions not associated with a local minimum of the incremental work are automatically eliminated in accord with the energy criterion of path stability. The augmented Lagrangian method is applied to convert the constrained minimization problem to a smooth unconstrained one. Effectiveness of the algorithm is demonstrated by the large deformation examples of simple shear of a face-centered cubic (fcc) crystal and rolling texture in a polycrystal. The algorithm is extended to partial kinematic constraints and applied to a uniaxial tension test in a high-symmetry direction, showing the ability of the algorithm to cope with the non-uniqueness problem and to generate experimentally observable solutions with a reduced number of active slip-systems.

Keywords:
solids, crystal plasticity, rate-independent constitutive equations, material stability, variational methods, incremental energy minimization, augmented Lagrangian method

4.Kursa M., Kowalczyk-Gajewska K., Petryk H., Multi-objective optimization of thermo-mechanical properties of metal-ceramic composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2014.01.009, Vol.60, pp.586-596, 2014
Kursa M., Kowalczyk-Gajewska K., Petryk H., Multi-objective optimization of thermo-mechanical properties of metal-ceramic composites, COMPOSITES PART B-ENGINEERING, ISSN: 1359-8368, DOI: 10.1016/j.compositesb.2014.01.009, Vol.60, pp.586-596, 2014

Abstract:
The optimization procedure is worked out for finding an optimal content of phases in metal–ceramic composites in case of conflicting objectives regarding thermo-mechanical properties of the material for a specific target application. Relationships between the material composition and effective properties of the composite are calculated by employing several methods of continuum micromechanics. A constrained minimization problem is solved for a single objective function based on the weighted squared distances from the best available thermo-mechanical properties for the material system selected. A compound block diagram is proposed for quick assessment of the consequences of deviating from the optimal composition. The developed procedure is applied to practical examples of Al2O3–Cu composites for brake disks and Al2O3–NiAl composites for valves of potential use in automotive industry.

Keywords:
Metal–matrix composites (MMCs), Thermomechanical, Plastic deformation, Micro-mechanics, Multi-criteria optimization

5.Petryk H., Kursa M., The energy criterion for deformation banding in ductile single crystals, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2013.03.004, Vol.61, No.8, pp.1854-1875, 2013
Petryk H., Kursa M., The energy criterion for deformation banding in ductile single crystals, JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS, ISSN: 0022-5096, DOI: 10.1016/j.jmps.2013.03.004, Vol.61, No.8, pp.1854-1875, 2013

Abstract:
The phenomenon of spontaneous formation of deformation bands in metal single crystals deformed plastically by crystallographic multislip is investigated theoretically by using the energy criterion of instability of a uniform deformation path. The second-order energy criterion for incipient deformation banding is derived in a time-continuous setting for a rate-independent elastic–plastic crystal. The need for selective symmetrization of the local interaction matrix for active slip-systems is demonstrated. A computational approach to deformation banding is developed by using non-convex constrained minimization of the incremental work with respect to increments in crystallographic shears and kinematical degrees of freedom. Calculated examples of deformation banding patterns in fcc single crystals are compared with experimental observations.

Keywords:
Metal crystal, Plasticity, Finite deformation, Laminate microstructure, Incremental energy minimization

6.Petryk H., Kursa M., Selective symmetrization of the slip-system interaction matrix in crystal plasticity, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.63, No.3, pp.287-310, 2011
Petryk H., Kursa M., Selective symmetrization of the slip-system interaction matrix in crystal plasticity, ARCHIVES OF MECHANICS, ISSN: 0373-2029, Vol.63, No.3, pp.287-310, 2011

Abstract:
The symmetry issue of the interaction matrix between multiple slip-systems in the theory of crystal plasticity at finite deformation is revisited. By appealing to possibly non-uniform distribution of slip-system activity in a representative space-time element of a crystal, symmetry of the slip-system interaction matrix for the representative element is derived under assumptions that have a physical meaning. This conclusion refers to active slip-systems only. Accordingly, for any given hardening law, a new symmetrization rule is proposed that is restricted to active slip-systems and leaves the latent hardening of inactive slip-systems unchanged. Advantages of the proposal in comparison with full symmetrization are illustrated by a simple example of uniaxial tension.

Keywords:
finite deformation, metal crystal, plasticity, hardening, symmetry

7.Czarnecki S., Kursa M., Lewiński T., Sandwich plates of minimal compliance, COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, ISSN: 0045-7825, Vol.197, No.51-52, pp.4866-4881, 2008
Czarnecki S., Kursa M., Lewiński T., Sandwich plates of minimal compliance, COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, ISSN: 0045-7825, Vol.197, No.51-52, pp.4866-4881, 2008

Abstract:
The subject of the paper is an optimal choice of material parameters characterizing the core layer of sandwich plates within the framework of the conventional plate theory in which the core layer is treated as soft in the in-plane direction. The mathematical description is similar to the Hencky–Reissner model of plates with transverse shear deformation. Here, however, the bending stiffnesses and the transverse shear stiffnesses can be designed independently. The present paper deals only with optimal design of the core layer to make the plate compliance minimal. Two core materials are at our disposal, which leads to the ill-posed problem. To consider it one should relax this problem by admitting composite domains and characterize their overall properties by the homogenization formulae. The numerical approach is based on this relaxed formulation thus making it mesh-independent. The equilibrium problem is solved by the DSG3 finite element method. The optimization results are found with using the convergent updating schemes of the COC method.

Keywords:
Minimum compliance problem, Sandwich plates, Topology optimization


Conference papers
1.Hołobut P., Kursa M., Lengiewicz J., Efficient modular-robotic structures to increase the force-to-weight ratio of scalable collective actuators, IROS 2015, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2015-09-28/10-02, Hamburg (DE), DOI: 10.1109/IROS.2015.7353836, pp.3302-3307, 2015
Hołobut P., Kursa M., Lengiewicz J., Efficient modular-robotic structures to increase the force-to-weight ratio of scalable collective actuators, IROS 2015, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2015-09-28/10-02, Hamburg (DE), DOI: 10.1109/IROS.2015.7353836, pp.3302-3307, 2015

Abstract:
A collective actuator is a self-reconfigurable modular-robotic structure which produces useful mechanical work through simultaneous reconfiguration of its constituent units. An actuator is additionally called scalable if its force-to-weight ratio does not depend on the number of its member modules. In this work, we consider scalable collective actuators built from spherical catoms with two connection types: strong but fixed and weak but mobile. We investigate how to construct these actuators in such a way, as to maximize their force-to-weight ratio. We present a number of designs of high strength, whose force capacities significantly exceed those of similar actuators reported previously.

2.Hołobut P., Kursa M., Lengiewicz J., A class of microstructures for scalable collective actuation of Programmable Matter, IROS 2014, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2014-09-14/09-18, Chicago (US), DOI: 10.1109/IROS.2014.6943113, pp.3919-3925, 2014
Hołobut P., Kursa M., Lengiewicz J., A class of microstructures for scalable collective actuation of Programmable Matter, IROS 2014, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2014-09-14/09-18, Chicago (US), DOI: 10.1109/IROS.2014.6943113, pp.3919-3925, 2014

Abstract:
The term Programmable Matter (PM) describes the class of future meta-materials of programmable and controllable properties and behavior, e.g., able to autonomously transform into an arbitrary shape. The robotic approaches towards PM are based on the concept of cooperation of millions of micro-robots (modules), acting at a very fine length-scale and collectively imitating deformation of a macroscopically continuous material. Recent ideas about reconfiguration of a collective of modules to obtain a desired overall mechanical response are promising. However, they are limited by the strength of individual connections between modules. In the present work, we propose a way of arranging spherical modules into microstructures, in which some connections are fixed and mechanically stronger, and the rest are active (reconfigurable) but weaker. If the fixed connections are sufficiently strong, the proposed microstructures perform the function of collective actuation by exerting forces proportional to their volumes. Two variants of a linear-actuator microstructure are presented and studied in more detail. A rotary-actuator microstructure is also introduced.

3.Kursa M., Kowalczyk-Gajewska K., Petryk H., Multi-objective optimization of effective thermo-mechanical properties of metal-ceramic composites, ECCOMAX 2012, 6th European Congress on Computational Methods in Applied Sciences and Engineering, 2012-09-10/09-14, Wiedeń (AT), Vol.1, pp.1-9, 2012
Kursa M., Kowalczyk-Gajewska K., Petryk H., Multi-objective optimization of effective thermo-mechanical properties of metal-ceramic composites, ECCOMAX 2012, 6th European Congress on Computational Methods in Applied Sciences and Engineering, 2012-09-10/09-14, Wiedeń (AT), Vol.1, pp.1-9, 2012

Abstract:
Micromechanical modelling of metal-ceramic composites has been carried out to obtain a material of required thermo-mechanical properties. Quantitative transition from phase properties and morphology to macroscopic properties of a composite has been modelled by mean-field approaches, including the self-consistent scheme. An optimization method has been developed for the objective function that expresses a distance between the required values of macro-variables and those determined for a given set of microstructural parameters. The presented example concerns application of Al2O3-Cu composite to brake disks.

Keywords:
multi-objective optimization, composite selection, metal matrix composites


Conference abstracts
1.Lengiewicz J., Kursa M., Hołobut P., Two-domain contact model of volumetric actuators, CMIS 2016, Contact Mechanics International Symposium, 2016-05-11/05-13, Warszawa (PL), No.P047, pp.90-91, 2016
2.Lengiewicz J., Kursa M., Hołobut P., Two-domain model of volumetric actuators, ICTAM XXIV, 24th International Congress of Theoretical and Applied Mechanics, 2016-08-21/08-26, Montréal (CA), pp.2632-2633, 2016
3.Kursa M., Petryk H., Algorithm for rate-independent plasticity of single crystals based on incremental work minimization, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), No.P180, pp.1-2, 2016
4.Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Micromechanical modelling of packing and size effects in particulate elastic-plastic composites, SolMech 2016, 40th Solid Mechanics Conference, 2016-08-29/09-02, Warszawa (PL), No.P099, pp.1-2, 2016
5.Petryk H., Kursa M., Constitutive and material instabilities in rate-independent single crystals deformed by multiple slip, ESMC 2015, 9th European Solid Mechanics Conference, 2015-07-06/07-10, Leganés-Madrid (ES), pp.#281-1-2, 2015
Petryk H., Kursa M., Constitutive and material instabilities in rate-independent single crystals deformed by multiple slip, ESMC 2015, 9th European Solid Mechanics Conference, 2015-07-06/07-10, Leganés-Madrid (ES), pp.#281-1-2, 2015

Keywords:
Crystal Plasticity, Slip-systems Selection, Incremental Energy Minimization

6.Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Description of packing and size effects in particulate composites by micromechanical averaging schemes and computational homogenization, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.571-572, 2015
Majewski M., Hołobut P., Kursa M., Kowalczyk-Gajewska K., Description of packing and size effects in particulate composites by micromechanical averaging schemes and computational homogenization, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.571-572, 2015

Abstract:
Different approaches to model packing and size effects are studied to model overall properties of particulate composites of different morphological features of phase distribution. The micromechanical schemes originating in the composite sphere model and its extension by morphologically-based pattern approach are taken as a basis. Analytical predictions are compared with results of computational homogenization performed on the generated representative volume elements of prescribed statistical characteristics.

Keywords:
micromechanics, morphologically representative pattern, computational homogenization, size and scale effect

7.Petryk H., Kursa M., The energy approach to rate-independent plasticity of metal single crystals, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.683-684, 2015
Petryk H., Kursa M., The energy approach to rate-independent plasticity of metal single crystals, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.683-684, 2015

Abstract:
In the modelling of metal single crystals in the framework of rate-independent plasticity, there are known difficulties caused by non-uniqueness in selection of active slip-systems. A related challenge is to predict emergence of non-uniform deformation patterns and the formation and evolution of experimentally observed microstructures. A new constitutive algorithm is presented that tackles those problems using the energy approach. It is based on asymptotically exact formulation of the set of constitutive equations and inequalities as a minimum problem for the incremental work expressed by a quadratic function of non-negative crystallographic slips. The calculated examples of deformation banding patterns and of reduction of multiplicity of active slip-systems in fcc single crystals are compared with the experimental observations.

Keywords:
crystal plasticity, slip-systems selection, incremental energy minimization

8.Lengiewicz J., Kursa M., Hołobut P., Actuation by reconfiguration—modular active structures to create Programmable Matter, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.799-800, 2015
Lengiewicz J., Kursa M., Hołobut P., Actuation by reconfiguration—modular active structures to create Programmable Matter, PCM-CMM 2015, 3rd Polish Congress of Mechanics and 21st Computer Methods in Mechanics, 2015-09-08/09-11, Gdańsk (PL), pp.799-800, 2015

Abstract:
We examine, analytically and numerically, forces produced by collective actuators–possible future building blocks of Programmable Matter. The actuators are composed of tiny spherical robotic modules which can strongly attach to their neighbors, and move by rolling over one another using electric or magnetic local propulsion mechanisms. An actuator works through collective reconfiguration–a coordinated motion of its constituent modules–which results in a global deformation of the structure. The simulations are performed using specially adapted discrete element method software, and account for friction and elastic deformations of modules.

Keywords:
programmable matter, active materials, actuators, mechanical strength, modular robots

9.Hołobut P., Kursa M., Macios A., Lengiewicz J., Evolving microstructures for scalable actuation in programmable matter, SolMech 2014, 39th Solid Mechanics Conference, 2014-09-01/09-05, Zakopane (PL), pp.209-210, 2014