dr hab. inż. Tomasz Lekszycki


Doktorat
1982Optymalne projektowanie układów lepko-sprężystych 
promotor -- prof. dr hab. inż. Zenon Mróz, IPPT PAN
380 
Habilitacja
2008-10-30Wybrane zagadnienia modelowania w biomechanice kości940
 
Ostatnie publikacje
1.Ambroziak M., Górecki A., Luterek M., Krakowian P., Lekszycki T., Bissenik I., Koperski Ł., Chłopek J., Skowronek P., Assessment of the Effect of Mechanical Vibrations and Platelet-Rich Plasma on the Healing of Tibial Stems Treated with the Elastic Carbon Stabilizer "Carboelastofix", ENGINEERING OF BIOMATERIALS / INŻYNIERIA BIOMATERIAŁÓW, ISSN: 1429-7248, Vol.XVI, No.119, pp.13-20, 20137p.
2.Lekszycki T., dell’Isola F., A mixture model with evolving mass densities for describing synthesis and resorption phenomena in bones reconstructed with bio-resorbable materials, ZAMM-ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK, ISSN: 0044-2267, DOI: 10.1002/zamm.201100082, Vol.92, No.6, pp.426-444, 2012

Streszczenie:

The multiform bio-mechanical phenomena occurring in bones grafted with the addition of artificial materials urge for the formulation of models which are sophisticated enough to describe their complexity. In the present paper we present a continuum poro-elastic mixture model in which two apparent mass densities are introduced to describe, at a macroscopic length scale, situations in which bone tissues and artificial materials coexist and interact. We focus on the final healing stage process when the bone remodelling becomes the dominant phenomenon. Artificial materials used are obviously to be bio-compatible and must resist to externally applied mechanical loads. More recently in order to favour bone tissue re-growth in grafts, which improves the long term performances of grafted bones, it has been conceived to use substitute materials which may be, similarly to bone tissue, bio-resorbed by osteoclasts and eventually replaced by newly synthesised living tissue. To account for resorption and synthesis phenomena suitable evolution equations are introduced for Lagrangian mass densities of the mixture constituents in which an integrodifferential operator defined on deformation fields appears. This operator is chosen to model some features of the coupling between mechanical compliance and biological bone tissue activity. The obtained system of integrodifferential equations is not trivial also when one considers one dimensional cases. Treating this simplified situations will allow us to individuate more easily some important remodelling scenarios. The numerical simulations which we present here show that the introduced model is promising and deserves to be developed to give previsions in more realistic applications.

Afiliacje autorów:

Lekszycki T.-IPPT PAN
dell’Isola F.-Università degli Studi di Roma "La Sapienza" (IT)
20p.
3.Madeo A., Lekszycki T., dell’Isola F., A continuum model for the bio-mechanical interactions between living tissue and bio-resorbable graft after bone reconstructive surgery, COMPTES RENDUS MECANIQUE, ISSN: 1631-0721, DOI: 10.1016/j.crme.2011.07.004, Vol.339, pp.625-640, 2011

Streszczenie:

We introduce a two-constituent porous continuum as a model describing the long-term growth/resorption phenomena in bone tissues grafted with bio-resorbable materials as driven by mechanical loads. The proposed model is able to account for the interplay between mechanical and biological phenomena which are known to be important for the bone tissue synthesis and the resorption of both bone tissue and bio-material. In particular, in the presented model the Lagrangian apparent mass densities of the natural bone and of the artificial material evolve in time according to precise ordinary differential equations. These latter are obtained by postulating a growth/resorption law and suitable constitutive equations conceived to account for the influence on bone resorption and synthesis of the action of different applied external loads as mediated by biological stimulus. The considered constitutive equations are chosen on the basis of the known biological phenomena occurring in bone resorption and synthesis. We present some numerical simulations for rod-bones subjected to axial external load. These numerical simulations allow for the description of the most desirable situation in which a gradual resorption of the artificial material takes place together with the contemporary formation of new bone, finally giving rise to an almost complete replacement of the artificial material with natural living tissue.

Słowa kluczowe:

Biomechanics, ODEs governing growth/resorption, Coupling between mechanical and biological stimuli, Artificial bio-resorbable material, Continuum solid-mixture model, Load-induced replacement of artificial material with natural bone tissue, Numerical simulations

Afiliacje autorów:

Madeo A.-Université de Lyon (FR)
Lekszycki T.-IPPT PAN
dell’Isola F.-Università degli Studi di Roma "La Sapienza" (IT)
20p.
4.Lekszycki T., Functional adaptation of bone as an optimal control problem, JOURNAL OF THEORETICAL AND APPLIED MECHANICS, ISSN: 1429-2955, Vol.43, No.3, pp.555-574, 2005
5.Dietrich L., Lekszycki T., Turski K., Identyfikacja charakterystyki mechanicznej materiałów sprężystolepkich na podstawie danych doświadczalnych, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.13, pp.1-59, 1995
6.Lekszycki T., Wariacyjne zasady w analizie i syntezie sprężystych układów z tłumieniem, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.37, pp.1-47, 1987
7.Lekszycki T., Mróz Z., On Optimal Support Reaction in Viscoelastic Vibrating Structures, Journal of Structural Mechanics, ISSN: 1539-7734, DOI: 10.1080/03601218308907432, Vol.11, No.1, pp.67-79, 1983

Streszczenie:

For a viscoelastic beam or frame structure that undergoes forced vibrations, the conditions for optimal support reaction are derived. Translation or rotation of supports are allowed and a functional expressed in terms of stress or strain amplitudes is minimized. Optimality conditions are derived using the concept of an adjoint structure and an illustrative example is presented for the case of beam vibration.

Afiliacje autorów:

Lekszycki T.-IPPT PAN
Mróz Z.-IPPT PAN
8.Mróz Z., Lekszycki T., Optimal support reaction in elastic frame structures, COMPUTERS AND STRUCTURES, ISSN: 0045-7949, DOI: 10.1016/0045-7949(81)90002-X, Vol.14, No.3-4, pp.179-185, 1981

Streszczenie:

The conditions for optimal support reaction are derived allowing for translation or rotation of supports and requiring the minimization of global elastic compliance or any other functional of stress or displacements. Two illustrative examples are discussed in detail where besides the optimal solutions, also the sensitivity of design with respect to varying support position and direction is studied.

Afiliacje autorów:

Mróz Z.-IPPT PAN
Lekszycki T.-IPPT PAN

Lista ostatnich monografii
1.
122
Lekszycki T., Wybrane zagadnienia modelowania w biomechanice kości, IPPT Reports on Fundamental Technological Research, 6, pp.1-264, 2007
Lista rozdziałów w ostatnich monografiach
1.
16
Gambin B., Lekszycki T., Kowalczyk T., Kowalewski T.A., Ziółkowski A., Pieczyska E.A., Stupkiewicz S., Scenariusze rozwoju technologii nowoczesnych materiałów metalicznych, ceramicznych i kompozytowych, rozdział: Biomateriały. Rola i strategia badawcza IPPT PAN w powstaniu nowoczesnych technologii materiałów współpracujących z ludzkimi tkankami, Wydawnictwo Naukowe Instytutu Technologii Eksploatacji PIB, 1, pp.181-222, 2010
2.
208
Lekszycki T., Tissue remodelling, ABIOMED Lecture Notes 3, rozdział: Bone remodeling in presence of osteoporosis, IPPT PAN, ABIOMED (Warszawa), Piekarski J. (Ed.), 3, pp.143-172, 2005

Prace konferencyjne
1.Krakowian P., Lekszycki T., Investigation and modeling of bone fracture healing, 5th International Conference on Advances in Mechanical Engineering and Mechanics, 2010-12-18/12-20, Hammamet (TN), pp.1-6, 2010
2.Lekszycki T., Selected problems of modeling in bone biomechanics, 5th International Conference on Advances in Mechanical Engineering and Mechanics, 2010-12-18/12-20, Hammamet (TN), pp.1-6, 2010

Abstrakty konferencyjne
1.Sciarra G., Lekszycki T., Bone remodeling description based on micro mechanical/biological effects, ECCM 2006, 3rd European Conference on Computational Mechanics, 2006-06-05/06-08, Lisbon (PT), Vol.CD-ROM, 2006