冷轧深冲板塑性应变比和屈服应力的理论计算及试验验证

Theoretical calculation and experimental verification of plastic strain ratio and yield stress of cold rolled deep drawing sheet

采用金属薄板的单向拉伸试验方法,测定了DC04和DC05板料在0°、45°、90°方向的屈服应力及Hill塑性应变比,并结合Hill48各向异性屈服理论,建立了预测任意方向屈服应力和Hill塑性应变比的理论计算模型,分析了其在0°、15°、30°、45°、60°、75°和90°方向的理论值和实验值的偏差。结果表明DC04和DC05板料的Hill塑性应变比的理论值和试验值的偏差均不超过3.5%,且在0°、45°、90°这3个方向上没有偏差;屈服应力的理论值和试验值的偏差均不超过2.6%,且DC04板料的最小偏差出现在45°方向仅为0.84%,DC05板料的最小偏差出现在0°和15°方向仅为0.51%。说明应用Hill48屈服理论计算DC04和DC05板料的屈服应力和Hill塑性应变比是十分准确的。

By using uniaxial tensile test method,the yield stress and the plastic strain ratio for DC04 and DC05 sheet at 0°,45° and 90°were measured,respectively. Based on Hill48＇s anisotropic yield theory,a theoretical model was developed to predict the yield stress and Hill plastic strain ratio in arbitrary directions,and the deviations between theoretical predictions and experimental values at 0°,15°,30°,45°,60°,75° and 90° were analyzed. The results show that the deviations between theoretical and experimental values of Hill plastic strain ratio for DC04 and DC05 are less than 3. 5%,particularly there is no difference at 0°,45° and 90°. The deviations between theoretical and experimental values of yield stress are less than 2. 6%,moreover the minimum deviation of DC04 is 0. 84% at 45°,and also the minimum deviation of DC05 is 0. 51% at 0° and 15° directions. It is shown that the calculated yield stress and Hill plastic strain ratio of DC04 and DC05 are very accurate by using Hill48 yield function.