16MnR钢应变疲劳裂纹扩展速率的实验研究

Analysis of the test of strain fatigue of 16MnR steel controlled by displacement or load

通过16MnR裂纹试样在载荷控制和位移控制下的应变疲劳给出了16MnR应变疲劳扩展速率;比较载荷控制与位移控制下裂纹疲劳扩展速率发现,两种方式的应变疲劳所获得的应变疲劳扩展速率差异明显;实验证明裂纹试样的应变疲劳扩展速率与疲劳过程中塑性变形功的大小密切相关。

Experiments on strain fatigue of 16MnR steel were conducted. Describing the fatigue crack growth with the energy method can theoretically reflect the essence of strain fatigue and is feasible for the actual measure. The delayed cycle curves of the cracks due to strain fatigue controlled by load or displacement are obtained and the average plastic strain energy dissipated per cycle under the control by load or displacement are calculated. By comparing the fatigue life under the control by load with that by displacement, it is clear that the growth rate of fatigue cracks controlled by displacement is greater than that by load. It is concluded that the growth rate of cracks of 16MnR steel due to strain fatigue becomes lower as the plastic deformation energy due to compression increases.