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研究目的:提出一种新的腐蚀疲劳损伤演化模型,建立基于损伤演化的腐蚀疲劳寿命预测模型。创新要点:将应力腐蚀损伤与疲劳损伤非线性耦合,建立腐蚀疲劳损伤演化律,依托实验确定腐蚀疲劳损伤演化参数,形成基于损伤演化律的腐蚀疲劳寿命预测模型。研究方法:采用理论研究与实验验证相结合的研究方法。选取特定材料设计应力腐蚀实验,回归应力腐蚀门槛值应力和损伤参数(图2);查阅疲劳实验数据建立变幅疲劳损伤模型,将应力腐蚀损伤与变幅疲劳损伤非线性累加形成腐蚀疲劳损伤非线性演化模型。根据腐蚀疲劳实验结果,验证腐蚀疲劳损伤演化模型并确定非线性损伤累加参数(图5和6),形成基于损伤演化律的腐蚀疲劳寿命预测模型。重要结论:从损伤力学角度,将材料的腐蚀疲劳损伤处理成应力腐蚀损伤与疲劳损伤的非线性累加,形成腐蚀疲劳损伤演化模型。结合LY12CZ铝合金的试验结果,验证了损伤演化模型的可行性。该方法可以为材料腐蚀疲劳的寿命评价研究提供新的思路。
Research purposes: To propose a new model of corrosion fatigue damage evolution and to establish a prediction model of corrosion fatigue life based on damage evolution. Innovative points: The stress corrosion damage and fatigue damage nonlinearly coupled to establish the evolution law of corrosion fatigue damage, relying on experiments to determine the evolution of corrosion fatigue damage parameters to form a corrosion fatigue life prediction model based on damage evolution law. Research Methods: A combination of theoretical and experimental research methods. Select the specific material design stress corrosion test, regression stress corrosion threshold stress and damage parameters (Figure 2); access to fatigue experimental data to establish a variable amplitude fatigue damage model, the stress corrosion damage and amplitude fatigue damage non-linear accumulation of corrosion fatigue damage Linear evolution model. According to the corrosion fatigue test results, the evolution model of corrosion fatigue damage was verified and the nonlinear damage accumulation parameters were determined (Figures 5 and 6) to form the corrosion fatigue life prediction model based on the damage evolution law. Important conclusions: From the point of view of damage mechanics, the corrosion fatigue damage of materials is treated as non-linear accumulation of stress corrosion damage and fatigue damage, forming the evolution model of corrosion fatigue damage. Combined with the experimental results of LY12CZ aluminum alloy, the feasibility of damage evolution model is verified. This method can provide a new idea for the life evaluation of material corrosion fatigue.