Sprawozdanie z badań podczas próbnego obciążenia wiaduktu 0-1 przeprawy drogowej przez rzekę Wisłę w ciągu Północnej Obwodnicy Puław
Przedmiotem niniejszego opracowania jest obciążenie próbne wiaduktu 0-1 przeprawy drogowej przez rzekę Wisłę w ciągu Północnej Obwodnicy Puław. Opracowanie zawiera wyniki badań obiektu podczas próbnego obciążenia oraz analizę porównawczą i weryfikację wyników teoretycznych i wyników badań.
Towards Understanding of Mechanics of Hernia Managed by Synthetic Mesh in Laparoscopic Operation: A Single Case Study
In this paper a research towards understanding of mechanics of ventral hernia operated with the use of Physiomesh Open image in new window implant and SecureStrap Open image in new window staples is described. Experimental and numerical studies are conducted for that purpose. Experimental works cover uni-axial tension tests of the implant samples and of the implant-staples-tissue system. Also experiments on implant-staples-tissue models, representing operated hernia, subjected to impulse pressure loading are performed. Based on that, constitutive model of the mesh has been identified and failure load of the staples has been determined. In the experiments on the operated hernia systems subjected to pressure loading safe loading level has been determined and failure modes connected to higher pressure values have been observed. Finally, in the numerical simulations of the operated hernia model, built according to FEM rules, it has been proved that failures observed experimentally result from exceeding of the load bearing capacity of the staples considered in this study.
The paper concerns flexural buckling and initial post-buckling of axially compressed columns made of aluminium alloy described by the Ramberg-Osgood relationship. The non-linear differential equation of the problem is derived using the stationary total energy principle and the assumptions of classical beam theory within a finite range. The approximate analytical solution of the equation leading to the buckling loads and initial post-buckling equilibrium path is determined by means of the perturbation approach. Numerical examples dealing with simply supported and clamped I-columns are presented, the effect of the material non-linearity on the critical loads and initial post-buckling behaviour in comparison to linear one is discussed too. The analytical results are compared with the FEM solutions to present a good agreement.
The initial post-buckling behaviour of a cold-formed channel member flange after its local buckling is investigated. An axially compressed column or beam subjected to pure bending is considered. The member material is assumed to follow a linear stress-strain relationship. The governing non-linear differential equation of the problem is derived using the minimum total potential energy principle. An approximate solution for the equation is found by means of the perturbation approach, which allows obtaining the critical buckling stress and the initial post-buckling equilibrium path. The bifurcation point is shown to be symmetric and stable. The proposed analytical solution is compared with finite element method (FEM) and finite strip method (FSM) results to check the validity and range of applicability.
The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling
The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created.