切口节点疲劳试验及损伤演化仿真研究

Study of fatigue characteristics of notched specimen by the method of fatigue experiment and numerical simulation

针对经常出现切口的船体结构节点连接处这一疲劳严重部位设计了一种切口试件。采用试验和数值计算方法研究切口节点在恒幅(CA)疲劳载荷下的疲劳特性。首先进行切口试件系列疲劳试验得到典型工况下的疲劳寿命值;然后引入基于损伤力学理论建立疲劳损伤演化模型,推导模型的迭代公式,采用非线性拟合方法拟合试验数据,得到损伤演化模型的相关参数;最后采用用户子程序技术建立疲劳损伤与单元刚度耦合算法进行有限元分析并将仿真结果与试验得到的疲劳寿命进行对比。结果表明:采用损伤-刚度耦合的仿真方法的分析结果与试验结果符合较好。

This paper investigates the fatigue characteristics of notched specimen with the method of fatigue experiments and numerical simulation,as fatigue failure always takes place at notched joint in ship structure.Firstly a list of fatigue experiments were conducted to get the fatigue failure life;and then the continuum damage mechanics model(CDM)was introduced and relative parameters of CDM model were verified by fitting the fatigue experiments results.Finally,the CDM model was introduced into the finite element software with the method of damage-element stiffness interaction by UMAT subroutine update and the UMAT was called to calculate the fatigue life of notched specimen and make a comparison and the calculating results agreed the experiments well.