Examination of SHPB type impact fracture toughness testing method by dynamic finite element analysis

Split Hopkinson Pressure Bar (SHPB) technique has been used to evaluate dynamic fracture toughness values of metals, polymers and composites. There are some attempts for such SHPB toughness testing that conventional static equation is applied to evaluate toughness under high speed loading condition by introducing gradually increasing load to the specimen. In this study, dynamic finite element analysis was performed to simulate SHPB type toughness testing with use of rubber buffer. A 2-D model including viscoelastic behavior of polymer specimen was developed, and it was found that the dynamic behavior experimentally obtained was well simulated using the model. Limitation of the use of the static analysis for impact toughness evaluation was also examined by considering acceleration effect on the stress intensity factor. The analytical result exhibited that the applicability of the static analysis may be assessed by considering the effect of acceleration on each of the test configurations.