• MeSH
• anizotropie MeSH
• biomechanika MeSH
• dospělí MeSH
• kryoprezervace metody   MeSH
• lidé MeSH
• modely kardiovaskulární * MeSH
• mrtvola MeSH
• nelineární dynamika MeSH
• perikard patologie   MeSH
• pevnost v tahu MeSH
• pilotní projekty MeSH
• uchovávání orgánů metody   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Several constitutive models have been proposed for description of mechanical behaviour of soft tissues containing collagen fibres. The model with aligned fibres is modified in this paper to take the dispersion of fibre orientations into account through angular integration and it is compared with the model that is defined through generalized structure tensor. The paper is focused on the effect of fibre dispersion on the resulting stress-strain behaviour predicted by both models analyzed. Analytical calculations are used for the comparison of the mechanical behaviour under a specific biaxial tension mode. The two models have been implemented into commercial finite element code ANSYS via user subroutines and used for numerical simulation resulting in a non-homogeneous stress field. The effects of the fibre dispersion predicted by both models being compared differ significantly, e.g., the resulting stress difference between both models is lower than 10% only in the case of extremely small dispersion of collagen fibres orientation (κ< (0.01 to 0.03)). These results are consistent with those of other related literature. The applicability of the model defined through the generalized structure tensor is discussed.

• MeSH
• anizotropie MeSH
• arterie fyziologie   ultrastruktura   MeSH
• fibrilární kolageny fyziologie   ultrastruktura   MeSH
• konformace proteinů MeSH
• lidé MeSH
• mechanický stres MeSH
• modely kardiovaskulární * MeSH
• modul pružnosti fyziologie   MeSH
• pevnost v tahu fyziologie   MeSH
• pevnost v tlaku fyziologie   MeSH
• pevnost ve smyku fyziologie   MeSH
• počítačová simulace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Soft tissues are pseudoelastic anisotropic materials; various formulas for their strain energy density have been proposed for modelling of their constitutive behaviour. However, the individual variance of elastic parameters is often more pronounced than their anisotropy, so that their constitutive relations can be modelled as either isotropic or orthotropic. Any hyperelastic model requires more mechanical tests to be input for an identification of its parameters than mere uniaxial tension tests; especially biaxial tension tests are very important also for isotropic hyperelastic materials. A design of a testing rig produced in cooperation of our institute with some local companies is presented. It enables us to carry out not only equibiaxial tension tests, but also some other biaxial tensile tests, because displacements in both mutually perpendicular directions can be controlled independently. The proposal of various types of biaxial tests is presented in the paper, with examples of their realization with porcine aortic wall tissue. The contribution focuses on ways of evaluation of the results and on identification of parameters of various constitutive models. The use of more mechanical tests in identification of constitutive parameters can improve the predictive capability of the models substantially.

• MeSH
• arterie fyziologie   MeSH
• biomechanika MeSH
• elastická tkáň fyziologie   MeSH
• mechanický stres MeSH
• pevnost v tahu MeSH
• počítačová simulace MeSH
• pojivová tkáň fyziologie   MeSH
• prasata MeSH
• pružnost MeSH
• statistické modely MeSH
• teoretické modely MeSH
• testování materiálů MeSH
• zobrazování trojrozměrné MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• hodnotící studie MeSH

Textile-based implant (mesh) treatment is considered as a standard of care for abdominal wall hernia repair. Computational models and simulations have appeared as one of the most promising approach to investigate biomechanics related to hernia repair and to improve clinical outcomes. This paper presents a novel anisotropic hypo-elastoplastic constitutive model specifically established for surgical knitted textile implants. The major mechanical characteristics of these materials such as anisotropy and permanent set have been reproduced. For the first time ever, we report an extensive mechanical characterization of one of these meshes, including cyclic uniaxial tension, planar equibiaxial tension and plunger type testing. These tests highlight the complex mechanical behavior with strong nonlinearity, anisotropy and permanent set. The novel anisotropic hypo-elasto-plastic constitutive model has been identified based on the tensile experiments and validated successfully against the data of the plunger experiment. In the future, implementation of this characterization and modeling approach to additional surgical knitted textiles should be the direction to follow in order to develop clinical decision support software for abdominal wall repair.

• MeSH
• chirurgické síťky * MeSH
• lidé MeSH
• operace kýly MeSH
• protézy a implantáty MeSH
• testování materiálů MeSH
• textilie MeSH
• ventrální hernie * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

V našem sdělení představujeme dosavadní výsledky společného výzkumu pracovišť Krajské nemocnice Liberec, a.s., a Technické univerzity v Liberci. Cílem projektu bylo sestrojit prototyp přístroje pro dvouosé měření mechanických vlastností lidské kůže in vivo. Dvouosé zatěžování umožní vyhodnocovat specifické parametry lidské kůže, které pro její anizotropii nelze zjistit při jednoosé tahové zkoušce. Prototyp byl nazván „BiEx“ (biaxial extensometer).

In our article we would like to present the results of joint research carried out at the Regional Hospital in Liberec and the Technical University of Liberec. The aim of this research was to design a prototype for biaxial measuring of mechanical properties of the human skin in vivo. Biaxial application of the load will allow for the evaluation of specific human skin parameters which cannot be determined during a uniaxial tensile test because of the skin anisotropy. This prototype was called “BiEx” (biaxial extensometer).

• Klíčová slova
• biomechanické vlastnosti kůže, dvouosý průtahoměr,
• MeSH
• biomechanika fyziologie   MeSH
• financování organizované MeSH
• fyziologie kůže MeSH
• lidé MeSH
• pružnost MeSH
• Check Tag
• lidé MeSH