热-机耦合交变疲劳的汽油机活塞环岸断裂特性

针对汽油机活塞承受交变的热负荷—机械负荷，提出用Palmgrem-Miner累积损伤法则对活塞进行断裂特性的分析研究，采用有限元法并根据应力幅—平均应力分布和Palmgrem-Miner累积损伤法则这两种理论分析方法对活塞槽底节点寿命预测进行仿真计算。研究结果表明，汽油机活塞环岸断裂是由于过高的交变热应力叠加交变的机械负荷所致；第1环槽表面上存在的循环波动热应力、材料蠕变及制造工艺也是环岸断裂的原因。

BREAKAGE CHARACTERISTIC OF THERMAL-MECHANICAL COUPLE ALTERNATING FATIGUE FOR GASOLINE ENGINE PISTON RING BANK

On the basis of the alternating load function of the thermal load-mechanical load on position of gasoline,the Palmgrem-Mine accumulative invalidation principle is carried out to analyze the characteristic of position failure and test the life of nodes of the piston ring groove bottom using the FE method and the principles of stress amplitude-mean stress dis- tributing and the Palmgrem-Mine principle.It is showed that the failure of position is the effect of the alternating thermal load and the alternating mechanical load and because of super- position of high thermal load and alternating mechanical load. Expecting the thermal stress and mechanical stress,the cycle fluctuating thermal stress and creep material and process exist- ing in the first annular groove is also the cause of the failure.