柴油机缸盖热-机耦合应力分析

采用有限元分析软件ANSYS,分析了某型柴油机缸盖的温度场分布和缸盖热应力以及缸盖在机械载荷作用下的应力场,然后运用热-机顺序耦合的方法,将热分析结果和机械载荷同时加载于缸盖,研究其在多种载荷作用下的应力场和变形情况.研究结果表明：缸盖温度最高点和热应力最大值出现在火力面鼻梁区;热-机耦合应力作用下,缸盖的最大应力点分布于缸盖螺钉头与螺孔的交界处以及火力面鼻梁区,缸盖承受的最大拉应力未超过材料的许容拉应力;热-机耦合应力作用下,缸盖的变形量很小,对其它零件的装配影响小,缸盖的整体变形呈现出对称性.

Analysis of Thermal-mechanism Coupled Stress Field of a Diesel Engine Cylinder Head

The temperature field,the thermal stress field and the stress field of a diesel engine cylinder head are analyzed under mechanism load with finite element analysis software ANASYS.The above temperature field results and mechanism load are taken as boundary condition to impose on the established model of cylinder head at the same time.Using the thermal-mechanism indirect coupled method,the stress field and displacement of cylinder head under effect of multiplicative loads are studied.The result indicates that the point of the highest temperature and the maximum thermal stress locate on the middle nose of firepower area; under thermal-mechanism coupled effect,the point of maximum stress locates on the interface of bolt head and screw of cylinder head,so that the middle nose of firepower area,the maximum pull stress the cylinder head undertook are less than that the material could survive.Under thermal-mechanism coupled effect,the displacement of the cylinder head is very small,thus has little influence to the fabrication of other accessories,and the global displacement of cylinder head performs symmetry.