Round Robin Test for Hat-Shaped Specimens in Split Hopkinson Shear Bar: A Numerical Study

This study presents the numerical simulation of a round-robin test conducted on two hat-shaped specimens, HS1 (+ 5.19°) and HS2 (5.19°), using a classical split Hopkinson pressure bar (SHPB) setup. The simulation was performed using apparatuses from Institut Teknologi Bandung (ITB), Swinburne University of Technology (SUT), the University of São Paulo (USP), and the University of Cape Town (UCT). Bar materials included AISI 4140, High Strength Steel, Maraging 350, AISI 4340, SAE 1055, and SS 17 - 4 PH, with diameters ranging from 10 to 24.99 mm. This study is conducted for planning the real experimental setup for near future of the round-robin test between institutions. A total of twelve cases were simulated, and the results were validated against experimental data, with an observed difference of 13.3. Thermal softening was also captured in the simulation using full Johnson-Cook parameters. The initial striker bar velocities were set to produce consistent incident wave amplitudes. Force equilibrium was achieved in most cases, except for the 5-USP setup, which had a low specimen-to-bar diameter ratio (40). The shear strain rate varied from 5.1 Ã� 10⁴ to 9.3 Ã� 10⁴ s^{â�� 1}, but this variation did not significantly affect the shear stress-shear strain results. Across all setups, the engineering shear stress-shear strain curves showed comparable trends. The flow stress for HS1 was 99.81 ± 3.84 MPa, while for HS2 it was 120.01 ± 4.48 MPa, with deviations across setups ranging from 1.7 to 4.3. These findings indicate that round-robin testing of hat-shaped specimens is expected to yield consistent test results across multiple setups and sample geometries and can be conducted through collaborative efforts between institutions. © Society for Experimental Mechanics, Inc 2025.