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Piston as important parts of the internal combustion engine, its work to withstand cycles of alternating gas pressure and thermal loads, and it also accompanied by the reciprocating inertia force, friction force and torsional force, etc., so the operation for a long time, it is easy to make it lower risk of local permanent deformation and charred. carbon material strength, which may in turn promote the machine stops running, In addition, some of the contact area of ??the piston group, the contact parts such as pistons and piston pin, piston pin and piston rod the contact parts, which will appear the phenomenon of stress concentration and fatigue failure due to the piston alternating mechanical stress. Considering these conditions, the design requirements of the piston is high. Piston structure optimization design to improve its service life, fatigue reliability, economy, and other performance indicators, and therefore has a very important significance for structural analysis and optimization design of the piston. For marine QT300 piston, using ANSYS software piston finite element analysis, draw the stress concentration in the field of temperature change and mechanical loads, and on this basis the piston structure optimized design, this article made the specific work of the following aspects: (1) the use of Pro / E software piston model to establish, and finite element analysis software (?) NSYS the piston temperature field, the calculation of stress and deformation analysis under mechanical load come various parts of piston temperature distribution and mechanical load, stress concentration. (2) based on the finite element analysis results by the current use genetic algorithm to optimize the design of the piston pin and piston pin, and local search optimization results using penalty function method, the final use of the piston pin hole profiled The design of the piston pin hole structure processing. By optimizing the design of the operation makes the upper end of the piston pin hole stress concentration has been significantly improved. (3) of the the piston head two-dimensional parametric modeling and design using ANSYS software optimization module of the piston head thermal loads optimized design, improved piston head size, thus reducing the thermal stress generated due to the temperature difference between the impact of the piston, thereby improving the reliability of the piston, and the reliability of the analysis module by ANSYS software analysis verified.
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