用应变能密度法分析纤维金属层板的微动疲劳特性

为研究纤维金属层板的微动疲劳特性，首先，基于三维坐标系下的临界平面法求解了纤维金属层板铝层临界平面上的应力和应变分量，并进一步求解了Smith-Watson-Topper （SWT）和I型Nita-Ogatta-Kuwabara （NOK）应变能密度参数；然后，建立了应变能密度参数-微动疲劳寿命关系式，并通过实验数据得到了寿命预测公式中的待定参数；最后，采用I型NOK应变能密度准则分析了铝层厚度、纤维层厚度、各层相对厚度和桥足圆角半径等对微动疲劳损伤位置和寿命的影响，并为纤维金属层板抗微动疲劳设计提出了一些合理化建议。结果表明:增加铝层厚度可以延长微动疲劳寿命，但增加纤维层厚度和桥足圆角半径不会改善微动疲劳特性。提出的方法可为分析纤维金属层板铆接和螺栓连接中的微动疲劳问题提供理论依据。 

Fretting fatigue characteristics of fiber metal laminates analyzed by using strain energy density method

In order to study the fretting fatigue characteristics of fiber metal laminates,stress and strain compo-nents on critical plane of aluminum layer for the fiber metal laminates were solved firstly based on critical plane method in three-dimensional coordinate system,and Smith-Watson-Topper (SWT)as well as Mode I Nita-Ogatta-Kuwabara (NOK)strain energy density parameters were solved further.Then,the relational expression of strain energy density parameter-fretting fatigue life was established,and the undetermined parameters in life prediction ex-pression were obtained through experiment data.Finally,the effects of aluminum layer thickness,fiber layer thick-ness,relative thickness of each layer and the round radius of bridge feet on fretting fatigue damage position and life were analyzed using Mode I NOK strain energy density criteria,and some rationalization advices were proposed for fretting fatigue resistance design of fiber metal laminates.The results show that by increasing the aluminium layer thickness,the fretting fatigue life can be improved;however,the fretting fatigue characteristics can not be improved by increasing fiber layer thickness and the round radius of bridge feet.The method proposed can provide theoretical references for the analyses of fretting fatigue problems in rivets and bolt connections for fiber metal laminates.