中速柴油机活塞镶圈断裂的有限元分析

为减小某中速柴油机活塞镶圈在热负荷状态下的应力集中，消除活塞镶圈断裂现象，文中对该中速柴油机活塞及活塞镶圈建立三维有限元模型，进行活塞镶圈温度场、热变形及应力场的有限元计算分析，计算时把温度场和热变形作为结构应力计算的边界，从而获得活塞镶圈在热负荷状态下的综合应力场，有限元计算结果与实际相符，表明采用单件分析、结合面自由度耦合的方法简单实用，适用于活塞镶圈热负荷状态下的应力分析，分析结果显示，在活塞镶圈的固定销孔处产生了较大的应力集中，固定销孔的结构不合理是活塞镶圈断裂的主要因素之一。

Finite Element Analysis of Ring Carrier Breaking in the Piston of Medium-speed Diesel Engine

In order to reduce the stress concentration and avoid the breaking of the ring carrier in the piston of a certain medium-speed diesel engine under thermal load, 3D finite element models of the piston and the ring carrier were established, with which the finite element calculation and analysis of the temperature field, the thermal deformation and the stress field for the ring carrier were carried out. The temperature field and the thermal deformation were considered as the boundary in the calculation of the stress field, thus obtaining an integrated stress field of the ring carrier under thermal load. The consistency between the finite element analysis result and the actual result reveals that the two methods of separate analysis and freedom degree coupling on the interface of the piston and the ring carrier are adaptive to the stress analysis of the ring carrier under thermal load, with the advantages of simpleness and practicality. The analyzed results show that a greater stress concentration would appear in the fixing hole of the ring carrier and that the structure fault of the fixing hole is one of the main reasons for the ring carrier breaking.