卸载后加载对扭杆刚度下降门槛值的影响

THE EFFECT OF RELOADING ON THE THRESHOLD OF TWISTING BAR WITH STIFFNESS DEGRADATION

基于损伤力学原理,推导了扭力矩门槛值表达式.并采用多次卸载后加载的方法进行定扭角刚度下降实验,得到卸载后加载的剩余扭力矩,进而计算每次加载后的剪应变门槛值.实验表明多次卸载后加载的方法可在一定程度上提高剪应变门槛值.此结论可以用于同类材料在工程应用中需要提高门槛值的构件.

In this paper, on the base of damage mechanics, the expression of torque threshold is deduced. The method of reloading after unloading is adopted to carry out the stiffness degradation experiment under certain twisting angles, and the residual torque is obtained, and then the threshold of the shear strain is calculated correspondent to every reloading. According to the experiment, the threshold of the shear strain is increased in certain degree under loading after unloading for many times. This conclusion can be used to increase the threshold of structures made of similar material which need higher threshold in engineering application.