Evaluation of Low Cyclic Thermal Fatigue Life and Safety for Diesel Engine's Pistons

摘要

The axisymmetric temperature fields and cyclic elastic-plastic stress-strain field and Mises' equivalent stress-strain fields of 12V180 and 42-160 engines pistons were calculated by means of the program "ADINAT/ADINA". According to the 'star-stop" wave, the tests of thermal-mechanical and isothermal low-cycle fatigue at elevated temperatures were carried out iwth the cylindrical notched specimens. The results of tests and calculations showed that the relationships between the equivalent strain ranges and fatigue lives accorded with the Manson-Coffin formula and wre not affected by specimens' shjapes and sizes and also ranges did not depned on specimens' shapes and sizes. Finally, these results were applied ot the pistons life prediction and safety evaluation and it was verified that the in-phase thermal-mechanical fatigue estimation was effective.