450MPa级船用钢冲击实验研究及Cowper-Symonds本构模型

应用SHPB实验技术,对450MPa级船用钢进行冲击实验研究,建立了材料的Cowper-Symonds本构模型.冲击实验发现,450MPa级船用钢的动态流动应力在变形过程中,具有二次非线性强化规律、存在强化转折点.当材料的变形小于转折点的应变时,动态流动应力随应变的增大而增大;当材料的变形大于转折点的应变时,动态流动应力随应变的增大而减小.文中还对Cowper-Symonds本构模型的适用范围进行了讨论.

Impact Experiment Study of Ship Building Steel at 450MPa Level and Constitutive Model of Cowper-Symonds

Applying the SHPB (Split-Hopkinson Pressure Bar) testing technique, the impact experiment study of ship building steel at 450MPa level was carried out, the constitutive relation of Cowper-Symonds for this kind of material was built up.Impact experiments indicate that the dynamic flow stress of ship building steel at 450MPa level has a characteristic of quadratic nonlinear hardening and a turning point of hardening during the process of steel deformation.When the material strain is less than the strain of the turning point, dynamic flow stress will increase with strain increasing, whereas, when the material strain is larger than the strain of the turning point, dynamic flow stress will decrease with strain increasing. In this paper, the range of application of the Cowper-Symonds relation was also discussed.