高强度柴油机活塞温度与应力场有限元分析及其结构改进

Finite Analysis of Temperature and Stress Fields and Structural Improvements for a Heavy-Duty Diesel Piston

结合柴油机活塞发展现状,针对某型号高强度柴油机,利用SolidWorks建立该柴油机活塞的三维模型,并用ANSYS对活塞进行有限元分析,讨论活塞在高温环境、最高燃烧压力或最大侧向力作用下的温度场、应力分布和变形情况*分析结果表明,活塞主要承受热应力和热变形,最大耦合应力在油道顶部,约270 MPa,最大变形出现在活塞顶部边缘,变形量约0.08%,变形随活塞高度降低而减小,在裙部略有上升*活塞头部在销孔方向上热变形大于耦合变形,两者差值随活塞头部高度降低而减小*活塞在垂直于销孔轴线方向上的耦合变形总体上大于平行于销孔方向的耦合变形。同时,燃烧室喉口、环槽和销座处应力集中明显,针对上述薄弱区域进行结构改进,发现改进后应力值均显著降低,这些结构改进对高强度柴油机活塞设计开发具有重要指导意义。

Considering the development statu?of diesel pistons*a three dimensional nxxkl of a heavy duty diesel I listen was established by using Solid Works software and the finite element analysis was carried out with ANASYS software to analyze the temperature field and the stress and deformation distribution under high ambient tem|>erature and maximum burst jurcssurc or maximum lateral force.Results show that the piston is mainly subjected to thermal stress and deformation.The maximum coupling stress,located at the top of oil gallery,is as high as 270 MPa.The maximum deformation occurs at the top edge of piston with a deformation of about 0.08%.The deformation decreases as the height of piston reduces and rises slightly at the skirt.The thermal deformation of piston head in the dircctioi|of pin hole is greater than the coupling deformation,and their difference decreases as the height of piston head reduces.The coupling deformation of the piston in the direction jierpendicular to the axis of pin hole is generally greater than in the direction parallel to the axis of pin hole.At the same time,it is found that the stress concentrations at the throat of combustion chamber,the ring groove and the pin scat are relatively obvious.Structural improvements for the above mentioned weak areas indicate that the stress values are significantly reduced.The improved results haw important guiding significance for the future piston design and development of heavy-duty diesel engines.