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本文首先分析船用柴油机热载荷的加载情况,然后确定强载零件的应力—应变迟滞循环;在此基础上用应变范围区分理论和滞回能范围理论,预测受热零件的低周热疲劳寿命.并和因低周热循环(起动和仃机)损坏的机器零件进行了比较,说明两个方法都具有一定的精确性.这是由于二者都考虑了疲劳和蠕变的交互作用.文中热疲劳和高温低循环疲劳的相当温度用的是最高温度T_2.在轴对称问题中,因为环向应力占主要地位,因此应力—应变范围以环向应力—应变范围为标志.
This paper first analyzes the loading condition of marine diesel engine’s thermal load and then determines the stress-strain hysteresis loop of the loaded part. Based on this, the theory of strain range distinction and the theory of hysteresis energy range are used to predict the low cycle thermal fatigue life of the heated part. And machine parts damaged by low cycle thermal cycles (start and stop) are compared to show that both methods have certain accuracy, since both consider the interaction of fatigue and creep. And the high temperature and low cyclic fatigue temperature is the highest temperature T 2. In the axisymmetric problem, because the circumferential stress is dominant, the stress-strain range is marked by the hoop stress-strain range.