高强化柴油机活塞加速热疲劳与等效寿命评估方法  

Study of Equivalent and Influence Laws of Accelerated Thermal Fatigue Life of Aluminum Alloy Pistons in Highly Strengthened Diesel Engines

作　　者：姬亚萌 张卫正[1] 原彦鹏[1] 芦红宇 郭金宝 徐云庆 JI Yameng;ZHANG Weizheng;YUAN Yanpeng;LU Hongyu;GUO Jinbao;XU Yunqing(School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China;Shandong Binzhou Bohai Piston Co.,Ltd.,Binzhou 256602,Shandong,China)

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]滨州渤海活塞有限公司,山东滨州256602

出　　处：《兵工学报》2022年第12期3008-3019,共12页Acta Armamentarii

基　　金：国防基础科研项目(B0920132004)。

摘　　要：针对高强化柴油机中的活塞在实机状况下热疲劳寿命难预测的问题,提出采用加速热疲劳方法的部件模拟试验寿命来预测活塞的实机寿命。基于临界面法,循环计算得到活塞在实机工作条件下和部件模拟条件下的仿真寿命结果,并运用活塞加速热疲劳试验数据对仿真的寿命数据进行验证,得到的寿命仿真计算值与试验值一致性较好,验证了临界面法的精确性;通过损伤等效分析,确定活塞实机标定工况下的寿命与台架寿命之间的关系;采用非线性拟合的方法,得到部件模拟条件试验条件下循环寿命与加载时间、最高温度之间的关联式。研究结果表明:在实机工况和部件模拟试验条件下,仿真计算得到活塞最先发生疲劳破坏的位置为喉口区域,说明二者的失效区域和失效特征具有一致性;在活塞喉口最高温度为408.6℃时,得到活塞实机标定工况下的寿命是部件模拟条件下的21.2倍;在活塞部件模拟条件下,最高温度相同时,活塞寿命随加热时间的减小而减小;加热时间相同时,活塞寿命随最高温度的增加而减小;根据拟合的关联式,得到活塞发生破坏时的活化能为61.5 kJ/mol。To solve the problem of predicting the thermal fatigue life of pistons in highly strengthened diesel engines under real conditions,an accelerated thermal fatigue method is proposed to predict the service life of pistons.The critical life method is used to calculate the cycle life of pistons under real working conditions and bench conditions.Piston accelerated thermal fatigue tests are carried out to verify the simulated life data,and the simulation data is in good agreement with the test results.Through damage equivalent analysis,the relationship between piston life under real working conditions and bench life is determined.The correlation between cycle life,loading time and maximum temperature under bench conditions is obtained by nonlinear fitting.Under real working conditions and bench test conditions,the simulation results indicate that the first spot where fatigue failure occurs is the throat area.The failure areas of the two are consistent.When the maximum temperature of piston throat is 408.6℃,the service life of piston under real machine calibration condition is 21.2 times that under bench condition.Under the condition of piston bench,when the maximum temperature is the same,the piston life decreases with the decrease of heating time.When the heating time is the same,the piston life decreases with the increase of the maximum temperature.According to the fitted correlation,the activation energy of piston failure is 61.5 kJ/mol.

关 键 词：实机条件 部件模拟条件 寿命等效 加速热疲劳试验 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]