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A stress-strain history in the material of real concrete structures is usually unknown. An effect of concrete degradation is analyzed to describe how the initial degradation parameter can describe the stress-strain history. The idea is to introduce the initial damage of the structure by the degradation parameter to calculate the internal variables of the constitutive model. Six numerical examples are proposed to verify the methodology for various loading conditions. Based on the obtained results, it was shown that unknown stress-strain history could be successfully represented using the original material parameters and the initial degradation of the concrete. The stress-strain behavior of the damaged concrete is successfully simulated and essential for the structural analysis of civil engineering structures. [ABSTRACT FROM AUTHOR]

This paper is the result of research and operation modeling of the new systems for cooling of cutting tools based on thermoelectric module. A copper inlay with thermoelectric module on the back side was added to a standard turning tool for metal processing. For modeling and simulating the operation of thermoelectric module, finite element method was used as a method for successful solving the problems of inhomogeneous transient temperature field on the cutting tip of lathe knives. Developed mathematical model is implemented in the software package PAK-T through which numerical results are obtained. Experimental research was done in different conditions of thermoelectric module operation. Cooling of the hot module side was done by a heat exchanger based on fluid using automatic temperature regulator. After the calculation is done, numerical results are in good agreement with experimental. It can be concluded that developed mathe-matical model can be used successfully for modeling of cooling of cutting tools. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a methodology used to identify causes of cracking nearby the welded joint on the underframe of wagon type Sgmns for the transportation of containers and swap bodies. Because of complex mounting, bending and welding technology of underframe bottom part, it was not possible to solve this problem with a commercial software. The aim of this analysis is to identify and register the residual stresses that appear after the process of mounting of the underframe bottom part. According to the TSI standard and norm EN 12663:2000, the fatigue strength analysis of Sgmns wagon for containers transportation was done. The analysis was done to discover kind of loads which induce cracks in the welded joints. The obtained results for the case of maximum vertical load were shown. The analysis of obtained results identified that cause of cracking on the bottom part of underframe of wagon type Sgmns is fatigue. [Copyright &y& Elsevier]