晶向对铝合金构件微动疲劳初始起裂的影响研究  

Effects of crystal orientation on crack initiation of fretting fatigue in aluminum alloy components

作　　者：王建 阮星源 WANG Jian;RUAN Xingyuan(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010

出　　处：《振动与冲击》2023年第19期130-136,共7页Journal of Vibration and Shock

基　　金：西南科技大学自然科学基金(20zx7124)。

摘　　要：交变荷载作用下铝合金板材及结构组件的微动疲劳问题是飞机安全服役所面临的主要挑战和技术难题,而微动疲劳影响因素辨识是微动疲劳评估及控制的关键。为促进飞机构件微动疲劳评估及控制技术的发展,利用晶体塑性有限元方法和子模型-全局模型耦合技术研究了飞机机身铆钉-平板结构在压、剪交变应力循环作用下裂纹萌生特征,探讨了以晶向表征的材料细观织构分布对铝合金试样微动疲劳的影响。研究发现,晶向分布将对晶体材料的弹性模量和屈服及硬化强度造成明显影响;晶向分布对微动疲劳接触面起裂部位的影响不明显,而对亚表面起裂部位影响比较显著;晶向分布对微动疲劳初始起裂寿命的影响比较明显。研究结果表明,晶向分布这一细观织构影响了晶体材料宏观尺度的弹性强度特征和塑性变形特征,并对金属构件微动疲劳初始起裂寿命、亚表面裂缝发轫位置及扩展特征均造成了影响。基于该研究结论,利用材料加工方法改变金属晶体试样浅表层的晶向分布状态,将可以对微动疲劳裂缝发轫及扩展起到抑制作用。Fretting fatigue problem of aluminum alloy plates and structural components under alternating loads is main challenge and technical difficulty faced by aircraft safety service,and identification of fretting fatigue influencing factors is the key to evaluation and control of fretting fatigue.Here,to promote development of fretting fatigue evaluation and control technology for aircraft components,the crystal plasticity finite element method and the submodel-global model coupled technology were used to study crack initiation characteristics of aircraft fuselage rivet-plate structures under action of compressive and shear alternating stress cycles.Effects of material microscopic texture distribution characterized by crystal orientation on fretting fatigue of aluminum alloy specimens were explored.The study showed that crystal orientation distribution can have an obvious impact on elastic modulus and yield as well as hardening strength of crystal material;effects of crystal orientation distribution on crack initiation position of fretting fatigue contact surface are not obvious,while it has a significant impact on crack initiation location of subsurface;effects of crystal orientation distribution on initial crack initiation life of fretting fatigue are relatively obvious.The study results showed that the crystal orientation distribution microscopic texture affects macroscopic elastic strength and plastic deformation characteristics of crystal materials,and also affects metal components fretting fatigue’s initial crack initiation life,subsurface crack originating position and propagation characteristics;based on the above conclusions,using material processing methods to change crystal orientation distribution state of shallow surface of metal crystal specimens can suppress originating and propagation of fretting fatigue cracks.

关 键 词：微动疲劳 裂纹萌生 初始起裂部位 晶向 晶体塑性有限元 

分 类 号：TH117.1[机械工程—机械设计及理论]