用等效平均损伤模型计算剩余寿命方法的研究

 分析了复杂载荷下材料的损伤累积过程和疲劳寿命计自身材料疲劳损伤与其不可逆电阻变化响应的联系。疲劳寿命计自身材料疲劳损伤演变、损伤累积过程以电阻变化速率和变化量显示了其全貌。假设其等效平均损伤等一般规律与金属材料的疲劳情况相类似,结合本文给出拟合精度很好的材料应力寿命曲线,得出随机载荷下剩余寿命计算的简便方法,具有较高可信度。初步实验验证很令人满意。

EXPLORATION OF THE FATIGUE REMAINING LIFE BASED ON AN EQUIVALENT AVERAGE DAMAGE MODE

The material fatigue damage accumulation procedure under complex loading is analyzed, and the relation between material fatigue damage of fatigue life gage itself under alternating loading and its permanent resistance change response to fatigue is discussed.The resistance accumulation quantity and resistance change rate reflect the material damage quantity and its evolution pattern. The fatigue equivalent average damage and damage accumulation procedure of the fatigue life gage material itself, displayed by the resistance change character are assumed to generally exist in common material.The equivalent resistance accumulation quantity corresponds to common metal material fatigue equivalent average damage quantity; fatigue failure damage quantity is not a constant value, but equal to the value at the point where the faitigue failure life curve and fatigue equivalent average damage curve intersect. A new stress cyclic number to failure curve suitable for most material from low to high stress cycle is developed. A new calculation method is advanced of material remaining life for random loading by using the fatigue failure curve and material equivalent average damage curve. This method is reasonable and quite satisfactory in the preliminary experimental verification.