基于热固耦合的柴油机气缸盖有限元分析

Finite Element Analysis of Diesel Engine Cylinder Head Based on Thermosetting Coupling

针对柴油发动机缸盖失效问题,在ABAQUS软件中以某现产柴油发动机构建仿真模型,通过实验数据标定模型温度边界,运用热固耦合理论对缸盖的温度分布、应力及变形分布进行仿真分析.对于分析中发现的热应力集中的缸盖鼻梁区,提出了缸心外凸、平齐和内凹的3种对比优化设计方案,并进行仿真验证.仿真结果表明,采用缸心内凹设计,降低缸心区域壁厚,可以有效降低鼻梁区最大应力.与试验对比,仿真模型的温度分布符合实际缸盖温度分布,验证了此方法的准确性,为解决柴油发动机缸盖失效问题提供了有效的优化设计方法.

A simulation model of a certain diesel engine was built by ABAQUS to solve the engine cracking prob- lem. The temperature boundary of the model was calibrated based on experimental temperature data. The temperature and stress/deformation distributions of the diesel engine were analyzed based on the thermosetting coupling theory. Three kinds of cylinder center surfaces including convex, flat, and concave surfaces were put forward due to the ther- mal stress concentration in the bridge of nose area. Simulations were carried out to verify these three projects. It showed that the stress of the concave surface was smaller than others. Reduction of the wall thickness of the center area decreased the maximum stress of the bridge of nose area. The temperature distribution of the analysis model was found to be consistent with the experimental results. The experimental results also verified the accuracy of the ther- mosetting coupling numerical simulation. In a whole, the investigation in this paper provides the theoretical basis for the optimization design of the cylincler head.