数値シミュレーションによるTRIP鋼の衝撃変形挙動の評価

抄録

Due to a strain-induced martensitic transformation (SIMT), a strength, a ductility and a toughness of the TRIP steel are enhanced. Recently, a low-alloyed high strength steel based on the TRIP steel is under development and its application to an impact absorption member is being investigated. Therefore, an evaluation of an energy absorption characteristic of the TRIP steels is quite essential. An experimental approach provides us the SIMT behavior under only static deformation since it is difficult to capture a moment of the phase evolution and temperature rise for the impact deformation. Thus, a computational approach with an appropriate constitutive model for TRIP steel can be powerful for its evaluation. Here, the impact compressive deformation behavior of TRIP steel is experimentally studied by the split Hopkinson pressure bar (SHPB) method at room temperature. Then, a finite element equation with the constitutive model for the TRIP steel proposed in the past is derived from a rate form of the principle of virtual work based on an implicit time integration scheme. After the results between the computation and the experiment for an impact compression are compared to confirm an validity of the computation, an impact deformation behavior under tensile deformation at a various temperature are evaluated.