为研究受力复杂工程构件的载荷、损伤与疲劳寿命的关系，文章根据船舶和舰艇中钛合金构件的使用及受力特点，以第四强度理论对现有的连续非线性损伤模型进行修正，提出更符合工程实际的非线性损伤模型，并根据单轴疲劳试验数据测算出其模型参数。分析所修正模型在不同疲劳应力下材料损伤累积量随疲劳循环次数的变化，并通过单轴疲劳卸载试样SEM观察分析，验证所修正的模型。然后再根据所修正模型设置复杂受力状态的疲劳实验，并通过非线性损伤修正模型、线性损伤模型及复杂受力疲劳实验数据的比较和分析，发现线性损伤模型在中小载荷下的寿命过于保守，而所修正的非线性损伤模型则更接近实验值，证明了所修正的非线性损伤模型在该区域的工程价值。%In order to research the relationship of load, damage and fatigue life for the stress complex engi-neering component, based on the stress characteristics of titanium alloy used in the ships and naval vessels, the authors modified the existing non-linear continuum damage model according to the fourth strength the-ory, hence proposed the non-linear continuum damage model that conforms better to engineering practice, and estimated the model parameters according to the uniaxial fatigue experimental data. By analysis of the changes in material damage accumulation volume vary with changes of fatigue cycles in different fatigue stress according to the modified nonlinear damage model, the suitability of the proposed model was verified by the SEM observation and analysis for the uniaxial fatigue unloaded specimens. According to the fatigue experiments in the stress complex state, through the comparison and analysis among the results from modi-fied non-linear damage model, the linear damage model and the fatigue experimental data in the stress complex state, it is found that the linear damage model gives a very much conservative estimation of the fatigue life within medium or low load region; and the modified model has higher accuracy and is more consistent with the experimental data. Therefore the modified non-linear damage model demonstrates its val-ue in the region engineering application.
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