一种基于黏弹性理论预测DP600钢板滞后回弹的新模型

发布时间：2018-05-24 02:44

本文选题：DP钢板 + 滞后回弹　；参考：《金属学报》2015年11期

【摘要】：通过加载不同预应变和保压时间获得了DP600钢板的室温滞后回弹响应.基于黏弹性理论,采用309 MPa恒应力室温蠕变实验,获得了预测滞后回弹过程的蠕变柔量函数.基于DP600钢板室温弹性和塑性加载响应,修正了线黏弹性本构方程的积分下限,将柔量函数与修正的应力率函数进行卷积,获得了影响滞后回弹过程的加载历史效应.再将加载历史应变波形与卸载脉冲叠加,获得不同预变形量的滞后回弹应变预测值.结果表明,滞后回弹初期应变率较高,之后应变率逐渐降低;随着预应变的增加,滞后回弹应变的绝对值逐渐递增,并且滞后回弹占总回弹比例逐渐增加;滞后回弹预测方向与瞬时回弹方向相同,与加载方向相反;相同时间段内,蠕变回弹应变比滞后回弹应变明显降低,与滞后回弹实验相比,蠕变恒应力与蠕变回弹应变的比值随预应变的变化规律呈现出良好的线性关系;基于黏弹性理论的修正模型所得到的预测值接近实验测量值,并能够较好地反映实验变化规律.
[Abstract]:The hysteresis springback response of DP600 steel plate at room temperature was obtained by loading different prestrain and holding time. Based on the viscoelastic theory, the creep compliance function for predicting the delayed springback process is obtained by using 309 MPa constant stress room temperature creep experiment. Based on the room temperature elastic and plastic loading responses of DP600 plates, the integral lower bound of the linear viscoelastic constitutive equation is modified. The compliance function is convolution with the modified stress rate function, and the loading history effect affecting the delayed springback process is obtained. Then the loading history strain waveform and the unloading pulse are superimposed to obtain the prediction value of the lag springback strain with different predeformation quantities. The results show that the initial strain rate of lag springback is higher, then the strain rate decreases gradually, and with the increase of prestrain, the absolute value of hysteresis springback strain increases gradually, and the ratio of hysteresis springback to total springback increases gradually. The prediction direction of hysteresis springback is the same as the instantaneous springback direction, which is opposite to the loading direction, and the creep springback strain is obviously lower than the hysteresis springback strain in the same time period, compared with the hysteresis springback experiment. The ratio of creep constant stress to creep springback strain shows a good linear relationship with the change of prestrain, and the predicted value obtained by the modified model based on viscoelastic theory is close to the experimental measured value and can reflect the experimental variation law well.
【作者单位】：北京理工大学材料学院;
【基金】：国家自然科学基金资助项目51175044~~
【分类号】：TG142.1

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