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In this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models that have been preliminarily checked for their reliability. The results of the calculations, namely, the relation between the internal pressure and the artery outer diameter, are verified against experimental responses and the applicability of the laws is assessed. New sets of Holzapfel constitutive relation constants are proposed for Eln+/+ and Fbln5−/− mice. Finally, the problem of carotid artery buckling is also discussed. The buckling pressures of the arteries are predicted using FEM models and nonlinear static analyses. These values are compared with the reference experimental results, which allow for further validation of the constitutive relations. The research emphasizes that computations and numerical methods enable an accurate description of bioengineering processes and behaviors but only if the models used are appropriately validated. [ABSTRACT FROM AUTHOR]

Within the six-parameter nonlinear shell theory we analyzed the in-plane rotational instability which occurs under in-plane tensile loading. For plane deformations the considered shell model coincides up to notations with the geometrically nonlinear Cosserat continuum under plane stress conditions. So we considered here both large translations and rotations. The constitutive relations contain some additional micropolar parameters with so-called coupling factor that relates Cosserat shear modulus with the Cauchy shear modulus. The discussed instability relates to the bifurcation from the static solution without rotations to solution with non-zero rotations. So we call it rotational instability. We present an elementary discrete model which captures the rotational instability phenomenon and the results of numerical analysis within the shell model. The dependence of the bifurcation condition on the micropolar material parameters is discussed. [ABSTRACT FROM AUTHOR]

Horizontal curves are one of the elements of road infrastructure where statistically a relatively high number of accidents have been reported. In the last 10 years in Poland, approximately 10% of all road accidents happened on horizontal curves of roads and was responsible for approximately 14% of all fatalities on Polish roads. Thus, this issue is important and requires extensive research and proper road safety treatments. One possible measure that may contribute to improvement of safety on road curves may be barriers. The purpose of this work is to assess, with use of numerical simulations, the performance of the 4-cable barrier systems installed on horizontal road convex curves. The most important parameters for road safety barriers are presented including the effect of various impact velocities and the radiuses of the road curves. [ABSTRACT FROM AUTHOR]

A novel sandwich composite footbridge is presented in the paper, as an example of practical application of laminated composites in civil engineering. The in situ static load tests of the footbridge before its acceptation for exploitation are shown and discussed. The results are compared with the corresponding ones from a numerical equivalent single layer model of the sandwich structure created within the framework of finite element method. The numerical solutions, are slightly higher than the measured in situ ones. Hence, it is concluded that the chosen method of structural analysis is efficient enough to recreate static behavior of the bridge and thus it is accepted for application in civil engineering. [ABSTRACT FROM AUTHOR]

Abstract: Theoretical values of two correction factors α s =5/6 and α t =7/10 are established for the respective transverse shear stress resultants and stress couples within the general, dynamically and kinematically exact, six-field theory of elastic shells. These values do not depend on the shell material symmetry, geometry of the base surface, the shell thickness, or any kind of kinematic and/or dynamic constraints. The analysis is based on the complementary energy density following from the transverse shear stresses acting only on the shell cross section. The appropriate quadratic and cubic distributions of the stresses across the thickness allow one to derive the consistent constitutive equations for the transverse shear stress resultants and stress couples with α s and α t as the respective correction factors. Four numerical examples of highly non-linear shell structures illustrate the influence of different values of α s and α t on the results. In particular, some influence of α t is noticed on the placement of bifurcation points. In dynamic problem of flight of three intersecting plates analysed with Newmark-type temporal algorithm, the value of α t influences the moment at which the relative error of total energy of the system begins to grow indefinitely leading to the solution failure. [ABSTRACT FROM AUTHOR]

Road restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed by EN 1317 standard was analysed. For this purpose, a full-scale crash test was performed and on the basis of this the validation process of numerical simulations was carried out. Correctly and carefully developed numerical simulations give unique insight into the impact mechanism and allows for comprehensive understanding of barrier responses. The accuracy of the numerical models was assessed by comparing the results of the simulation with the crash test. The research showed that the analysed barrier work correctly, it contained and then properly redirected 1500 kg car back onto the road and ensured safety for the vehicle occupants at the same time. • Methodology of numerical modelling of cable barrier. • Experimental and numerical analysis of the cable barrier in modified TB32 crash test • Validation of the numerical model. • Detailed analysis barrier damage. [ABSTRACT FROM AUTHOR]