Q460D高强钢及对应的ER55-G型焊材的GTN模型参数标定

Parametercalibration of GTN model of Q460D high strength steel and corresponding ER55-G welding material

分别对取自Q460D高强钢及对应的ER55-G型焊材的9个光滑圆棒试件和18个圆周平滑槽口试件进行单向拉伸试验,获得基本的力学性能参数、荷载—位移曲线和真实的应力—应变曲线.并通过对18个圆周平滑槽口试件的有限元模拟结果与试验数据进行对比,标定得到Q460D高强钢材及对应的ER55-G型焊材的GTN损伤模型参数.利用标定的GTN模型损伤参数对在Q460D高强钢及对应的ER55-G型焊材取材的圆棒试件的断裂点进行预测,验证所标定参数的准确性.并进一步分析初始微孔洞体积比f0、临界微孔洞体积比fc、最大微孔洞体积比fF和形核孔洞体积分数fN四个损伤参数对断裂预测结果的影响.

The monotonic loading tests were carried out on nine smooth round bars and eighteen circumferentially smooth-notched bar specimens of Q460D high strength steel and the corresponding ER55-G welding material to obtain the basic mechanical properties,load-displacement curves and true stress-strain curves.The GTN model parameters of Q460D high strength steel and the corresponding ER55-G welding material were calibrated according to the experimental and finite element analysis results of eighteen circumferentially smooth-notched bar specimens subjected to monotonic loading.Moreover,the calibrated GTN damage parameters were used to forecast the fracture points of coupon specimens of Q460D high strength steel and the corresponding ER55-G welding material,so as to verify the accuracy of the calibrated parameters.Furthermore,the influences of four damage parameters,including initial void volume fraction f0,critical void volume fraction fc,final failure void volume fraction fF and nucleating volume fraction fN,on fracture prediction results were further analyzed.