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某飞机起落系统中某重要构件在飞机往复起落中承受循环冲击载荷作用,需对该构件的冲击疲劳强度进行分析。损伤力学方法对冲击疲劳问题来说是一种新的分析方法。首先分析构件在静载荷作用下的细节应力,判明疲劳危险点,接着分析得到危险点在冲击载荷作用下的应力响应。然后构建冲击型损伤演化方程,并识别其中的材质参数,提出将应力响应视为载荷谱的应力应变场—损伤场解耦处理方式,发展了损伤力学—有限元法,使其可用于预估构件冲击疲劳裂纹萌生寿命。而后应用该方法对构件在冲击疲劳载荷与非冲击疲劳载荷作用下的疲劳裂纹萌生寿命进行预估,得到寿命预估结果,进而比较得到冲击疲劳载荷作用下和非冲击疲劳载荷作用下构件寿命的当量关系,为该构件的等效疲劳试验提供重要参考依据。
An important component of landing system of an airplane is subject to cyclic impact load during reciprocating landing of the aircraft, and the impact fatigue strength of the aircraft component needs to be analyzed. Damage mechanics is a new analytical method for impact fatigue problems. First of all, the detail stress under the static load is analyzed to find the point of fatigue. Then the stress response of the dangerous point under the impact load is obtained. Then, the evolution equations of impact damage are constructed and the material parameters are identified. The stress-strain field-damage field decoupling method is proposed, in which the stress response is regarded as the load spectrum, and the damage mechanics-finite element method Component impact fatigue crack initiation life The fatigue crack initiation life of the component under the impact fatigue load and the non-impact fatigue load is estimated by using the method, and the life prediction result is obtained. Then the life expectancy of the component under the impact fatigue load and the non-impact fatigue load is obtained Equivalent relationship for the components of the equivalent fatigue test provides an important reference.