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为分析激光冲击AZ31B镁合金薄板背面的动态响应与残余应力分布规律,采用PVDF贴片传感器对冲击波进行测量得到压电波形与动态应变响应曲线,X射线衍射仪对薄板背面冲击区域中心与其边界点冲击前后残余应力进行测量,结合冲击波的传播规律,解释了应变变化对残余应力变化的影响。结果表明,冲击波从冲击区域向冲击区域外的传播过程中,能量衰减明显。动态应变响应曲线类似正弦曲线,冲击区域在弹塑性双波加载时动态应变骤然增高,随后波动上升,最终的静态应变呈现拉应变与检测出的残余应力变化规律相符,冲击区域边缘的动态应变响应相较冲击区域变化缓和,弹塑性双波的卸载与加载过程并未引起动态应变的大幅突变,静态应变变化不大与残余应力的变化规律一致。
In order to analyze the dynamic response and residual stress distribution of laser shock on the back of AZ31B magnesium alloy sheet, the piezoelectric waveform and dynamic strain response curve were measured by PVDF patch sensor. The influence of X-ray diffraction on the center of impact area and the boundary point The residual stress before and after impact measurement, combined with the propagation of shock wave, explained the impact of strain changes on residual stress. The results show that the energy attenuation is obvious when the shock wave propagates from the impact area to the outside of the impact area. The dynamic strain response curve is similar to a sinusoidal curve. The dynamic strain increases sharply in the elastic-plastic double-wave loading zone and then fluctuates upward. The final static strain shows a tensile strain consistent with the detected residual stress. The dynamic strain response at the edge of the impact region Compared with the change of impact area, the unloading and loading process of elastic-plastic double wave did not cause the sudden change of dynamic strain. The change of static strain was not obvious and the variation of residual stress was consistent.