装载机动臂的裂纹扩展寿命预测  

Prediction of crack propagation life of loader boom

作　　者：黄伟[1] 全威 龚智伟 何继锟 王敏 HUANG Wei;QUAN Wei;GONG Zhiwei;HE Jikun;WANG Min(College of Mechanical Engineering,Guangxi University,Nanning 530004,Guangxi,China)

机构地区：[1]广西大学机械工程学院,广西南宁530004

出　　处：《中国工程机械学报》2021年第4期307-312,共6页Chinese Journal of Construction Machinery

基　　金：广西创新驱动发展专项资金资助项目(科技重大专项)(桂科AA18242033、桂科AA1824045)。

摘　　要：装载机动臂在服役过程中所产生的疲劳裂纹直接影响作业安全。基于线弹性断裂力学理论,首先采用有限元法,在动臂铰孔处内壁建立半椭圆形的初始裂纹模型,分析计算在单个循环周期内载荷峰值下的应力强度因子值。然后通过数值拟合来研究在裂纹扩展过程中应力强度因子幅与裂纹深度的对应关系,在绘制?K-a曲线后利用Paris公式预测动臂的裂纹扩展寿命。结果表明:应力强度因子幅随着裂纹深度的增大而增大,而裂纹的初始长度也影响着动臂的裂纹扩展循环次数,呈现显著的反向变化关系。研究成果为装载机动臂的可靠性设计提供了一种新途径,并有助于疲劳寿命的快速预测。The fatigue crack of loader boom in service directly affects the operation safety. Based on the theory of linear elastic fracture mechanics,a semi elliptical initial crack model is established on the inner wall of the reamed hole of the boom by using the finite element method,and the stress intensity factor value under the peak load in a single cycle is analyzed and calculated. Then,the corresponding relationship between the stress intensity factor amplitude and the crack depth is studied by numerical fitting. After drawing ?K-a curve,Paris formula is used to predict the crack growth life of the boom. The results show that the amplitude of stress intensity factor increases with the increase of crack depth,and the initial length of crack also affects the number of crack growth cycles of boom,showing a significant reverse change relationship. The research results provide a new way for the reliability design of loader boom and help to predict the fatigue life quickly.

关 键 词：装载机动臂 动力学仿真 有限元法 应力强度因子 裂纹扩展寿命 

分 类 号：TH243[机械工程—机械制造及自动化]