激光冲击金属板料变形的 最小激光能量估算及其实验研究

介绍了激光冲击板料变形的机理和冲击波产生的原因,提出了激光冲击板料变形中激光－能量转换体－靶材系统的爆轰波压力估算式。根据此压力估算式和材料的动态屈服强度,对激光冲击板料变形中所需的最小激光能量进行了估算,板料厚度为0.5 mm,约束凹模孔径Φ20 mm,在光斑直径6 mm,脉宽25 ns条件下的不锈钢靶材变形所需的最低脉冲能量大约为11 J。实验结果表明估算的最小激光能量与板料变形所需的能量阈值基本一致,且板料变形量随激光能量的增加呈非线性增大。最小激光能量的估算以及能量与板料变形的实验研究为板料变形的精确控制和预测提供了理论依据。

Study on calculation of minimum laser energy of sheet metal deformation by laser shock forming

The mechanism of laser shock deformation and the reasons of producing the shock wave were introduced, and the estimated formula of shockwave pressure was put forward, which shows clearly the relation between the peak value of shockwave and the overlay, energy absorbed layer, sheet metal properties and laser parameters. Based on both the formula and the tensile yield strength of sheet metal, minimum laser energy needed by deformation was estimated, the results show that the lowest pulse energy needed by the target deformation of stainless steel is about 11 J under the conditions of sheet thickness of 0.5 mm, the bore diameter of cavity die of 20 mm, the beam diameter of 6 mm and the pulse width of 25 ns. The experimental results also show that minimum energy calculation accords with critical value energy in a nonlinear way. By of deformation, and the deformation increases with the increase of laser studying on the calculation of minimum laser energy and the deformation experiment, the paper provides exactly a theoretical foundation for controlling and predicting deformation of sheet metal.