柴油机陶瓷活塞陶瓷与金属双材料热应力研究

Investigation on Thermal Stress of Bimaterial Material Piston of Ceramics and Metal in a Diesel Engine

本文通过有限元计算，分析了１３５绝热柴油机ω型燃烧室陶瓷与金属双材料活塞的热应力状态。为提高计算精度，计算中对陶瓷涂层及两种材料界面处的单元进行了细致划分，同时引入了陶瓷与金属两种材料热膨胀系数随温度变化函数。计算使用了Ａｄｉｎａ有限元软件包。计算结果表明，陶瓷活塞的陶瓷涂层内的最大热应力比铝合金部分热应力高出１个数量级，活塞陶瓷涂层最大热应力出现在活塞燃烧室上圆周边缘处。文中还分析了不同燃烧室结构参数对陶瓷涂层热应力状态的影响，为优化设计陶瓷活塞提供了依据。

Thermal stress of ω shape piston bimaterial of ceramics and metal of a 135 diesel engine was analyzed using finite element method in the paper.In order to make the calculating results more accurary,a refined finite element mesh was created around the ceramics layer and the part of interconnection of ceramics and metal.The changes of thermal inflation coefficient of ceramics and metal with temperature were considered in the calculation.The results show the maximum stress of ceramics layer is over ten times larger than the stress of aluminum part,the maximum thermal stress occurred at upper edge of combustion chamber.The influences of combustion chamber parameters on thermal stress of ceramics layer were analyzed,which provided the foundation for optimally designing ceramics piston of a diesel engine.