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The main objective of this study is to estimate the accuracy of the method for the determination of material parameters based on laboratory data from a single experiment conducted on a sample working in a nonuniform stress state, registered by the digital image correlation system (DIC). The idea of the method is based on the inverse analysis, in which the material parameters are determined by the optimization procedures using the cost function being the result of comparison of the laboratory data with the results of FEM simulation, wherein the whole deformation areas are taken into account. This paper presents the method described above applied on the determination of isotropic hardening parameters for an aluminum alloy material. Tests were carried out on the aluminum plates with nonuniform geometry subjected to tensile deformation. A comparison of the effect of sample geometry on the results was made, and an analysis of the impact of variation of material parameters on the value of the cost function was carried out.
No abstract is provided for this article.
No abstract is provided for this article.
No abstract is provided for this article.
The main goal of this paper is to propose the performance parameter for binder which is good for quality prediction of asphalt mixture in frame of resistance to permanent deformation (rutting). Additionally, correlation between, proposed by the authors, repeatable shear creep-recovery test carried out on binder and bituminous mixture rutting test is under evaluation. The results are analysed and correlation between the proposed functional parameter and rut depth is shown. Thanks to that it is possible to claim that expensive rutting test procedure can be assisted with simple test carried out in dynamic shear rheometer at the initial mix design procedure.
Przedstawiono metody symulacji statecznościowego zachowania się zginanych elementów konstrukcji stalowych z wykorzystaniem modelowania skończenieelementowego.Rozważania dotyczą belek nieidealnych, wykonanych z walcowanych kształtowników szerokostopowych HEB i wąskostopowych IPE, o wstępnym wygięciu odpowiadającym pierwszej formie zwichrzenia
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Chapter 8 written by Gajewski and Kowalski reviews the most popular methods used in modeling exchange rates, i.e. purchasing power parity and interest rate parity. They attempt to join the two approaches in the empirical part of the study.
No abstract is provided for this article.
Since asphalt mixtures are based on bituminous binders, a complex organic viscoelastic and time-temperature dependent material, they naturally tend to change their performance. Due to increasing traffic and axle loads, fatigue resistance is one of the most important properties of asphalt materials. The standard procedure of asphalt mixture evaluation is determining their fatigue resistance, but it is also possible to determine the fatigue resistance of bitumen on binders level. This article presents the research results of asphalt binders fatigue resistance, two paving grade bitumens and one polymer modified bitumen, in unaged and aged states. Asphalt binders were tested using three methods according to the Superpave criterion, the time-sweep fatigue test and the linear amplitude sweep test (LAS). Analysis and evaluation of the test results were carried out due to fatigue and time consumption of the testing procedure. In terms of determining the fatigue phenomenon, both in bitumen and asphalt mixture levels, the most critical aspect is the time severity of the tests and the necessity to perform such advanced testing on many test specimens. The results show that the G*·sinδ parameter should not be used to validate the fatigue life of bitumen. The result from fatigue time-sweep and LAS tests appear to give similar outcomes and correlate better, especially the LAS in higher strain levels. Furthermore, regarding test time consumption, LAS requires less time to perform and gives a more flexible approach to determining bitumen fatigue life.
Present approach to design of steel I-section beam-columns distinguish two design situations of elements subjected to one directional bending and compression in which they are sensitive either to the flexural failure (second order in-plane bending and compression) or to the flexural-torsional failure (second order spatial bending, warping torsion and compression). This paper refers to the former case of member failure and aims in the development of finite element numerical modelling technique that would be useful for the verification of analytical resistance criteria of perfect beam-column elements subjected to different support and loading conditions. Impact of different boundary conditions and nonuniform bending on the member resistance is assessed and concluding remarks in relation to the proposed analytical formulation are drawn.
