基于室温下的Instron静态压缩试验和霍普金森压杆(SHPB)动态试验,利用Johnson-Cook本构模型,并采用参数识别法和最小二乘法拟合相应的本构参数,确定了适合于聚碳酸脂的动态本构方程.发现低应变率下,理论值与实验值吻合较好;高应变率下,理论值与实验值的屈服点吻合较好.将其用于描述飞机风挡材料,应用非线性有限元程序LS-DYNA3D进行了鸟体撞击风挡的数值仿真计算.由风挡和鸟体的变形过程以及风挡的位移时程曲线可知,实验结果和数值结果吻合较好.
Based on the dynamic experiment of split-Hopkinson pressure bar (SHPB) and the static compression experiment of Instron at the room temperature,a dynamic Johnson-Cook constitutive equation of polycarbonate is proposed by using the least square and parameter identification methods to fit the corresponding constitutive parameters.It is found that the theoretical values accord well with the experimental ones at lower strain rates while they accord well with each other only at yield points at higher strain rates.In addition,the model is employed to simulate the aircraft windshield under bird impact by using the nonlinear finite element software LS-DYNA3D.The results show that the deformations of the bird and the windshield as well as the history curve of the windshield displacement in the simulation accords well with those in the experiments.