Сhief designer of the tank-car project** R. G r a b o r o v Head of group of technical settlement** V. P o s o h o v Senior Lecturer Department of Repair and operation of cars and military vehicles National academy of the National guards of Ukraine Zakhysnykiv Ukrainy sq.,
In this paper static strength analysis of body and frame of the covered railcar model 11-9962 with the weight of 0.922 MN is carried out. Numerical study of freight railcar is carried out by the finite element method. Calculation model consists of plates and beams linked together at the nodal points simulating the elements of the railcar body. The main objective of the static strength analysis was to evaluate strength and bearing capacity of railcar structure and to evaluate the conformity of freight railcar structure to regulatory requirements. Typical for the static loading mode is a single and continuous application of an external load, gradually increasing from zero to the maximum value. The calculation scheme of railcar takes into account forces acting on it in operating conditions. Load modes considered are: I, III basic modes, collision and jerk mode, repair modes (when jacking up a railcar by jacks), railcar loading mode (on possibility of using electric and autoloader for loading), roof strength test. From the analysis results it follows that stresses in all body elements and frame of the covered railcar model 11-9962, for all design modes, do not exceed the permissible values, and railcar structure conforms to the current regulations. Analysis showed good agreement with the test results for strength of the prototype railcar.
The paper is devoted to the search for technological methods of increasing the resistance of the stamp tool for hot deformation. New non-standard combinations of cyclization schemes and parameters of thermocycling processing within the regime were developed. This is allowed the creation of managed structural states in the metal due to the grinding of grain, the creation of high density of defects, and the acceleration of diffusion processes to effectively manage the structure, increase the mechanical, operational properties and prevent the destruction of the working surfaces of the tool. New modes of thermocycling treatment, which have a positive effect on the mechanical characteristics of HNM5 steel, have been developed and tested. The conducted heat treatment in experimental modes, consisting of thermocycling treatment as a preliminary, quenching and tempering as the final, allows obtaining a more homogeneous structure with the preservation of fine grain and a given hardness. The grain size of the steel HNM5 structure after the use of thermocycling treatment decreases from 5–6 to 7–8 points, and after the final heat treatment – to 9–10 points.
Keywords: stamp of hot deformation, thermocycling treatment, strength, relative narrowing, thermal resistance.
The article deals with the development of approach for providing of structural strength of complicated thin-walled machine-building structures, which operate in the conditions of geometric and physical nonlinearities using design solution validation. The developed approach is based on the use of mathematical model for stress-strain state taking into account geometric and physical nonlinearities and methods of approximation for constructing functions describing the evaluated characteristics of the object under study. The various factors behind the search for design solutions (including characteristics of strength, rigidity, technological and economic factors), are being added into this function. The developed algorithm for rational parameters search, which takes into account the peculiarities of the response surface shape observed in solving applied problems, is applied to them. In this case, the solution is sought over the whole range of parameter changes. Thus, in the search process, global trends of changes in design decisions are taken into account, and not local ones, as in other approaches. This allows obtain a rational solution that is stable to changes in parameters, which are possible in course of design work and production conditions. Investigations are illustrated on the freight rail-car, tractor cabin frame, carrier personnel hull.
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