基于韧性耗散模型的损伤定量分析方法

材料的静力韧性便于工程测量，对疲劳损伤较其它宏观损伤变量更敏感。本文以材料静力韧性为宏观损伤变量，依据疲劳过程中金属材料韧性随疲劳循环加载而变化的实验结果的规律分析，得到了应力和循环数表达的损伤演化方程和损伤累积模型。该模型能较好地反映加载顺序的影响。推导出该疲劳损伤累积模型在多级加载下的递推公式。经四种金属材料疲劳试验数据验证结果表明，该模型预测疲劳寿命是较为满意的。由于疲劳试验数据分散性大，结果有待进一步验证。

A New Approach for Fatigue Damage Quantitative Analysis on the Basis of Toughness Degradation

Material toughness degradation parameter is easier obtained for engineering measurement and is more sensitive to fatigue damage than other fatigue damage parameter. In this paper, Material toughness degradation was selected for macrocosm damage parameter. On the basis of the analysis for experimental results of metal toughness degradation change behavior in the fatigue process, a new damage evolution equation and damage cummulative model that expressed by stress and cyclic number were proposed. This model included the effect of the loading sequence, which can appropriately describe the fatigue damage evolution behavior. The recurrence formula of the fatigue damage model was derived under multilevel loading. The fatigue test data for four kinds of material were used to verify the model proposed in this paper. The results show that the good agreement was achieved with this model to predict fatigue life, compared with that of Miner's rule. Since the fatigue test data has large scatter, the results need more data to be verified.