Perpustakaan Digital ITB

There are two main challenges arising in the modern transportation industry, i.e. lightweight and crashworthiness. In order to meet these challenges, it requires suitable material, which is known its characteristics under certain conditions. Material has now analyzed more specifically on its dynamic characteristics because the loads which is occurs in the reality is the most dynamic loads. The Hopkinson pressure bar test is a test which has been commonly performed for dynamic material characterization. However, there has been no standard testing until now. Split Hopkinson Shear Bar (SHSB) is a modification of Split Hopkinson Pressure Bar (SHPB). SHSB is a SHPB which uses shear loads. In SHSB, there are three methods, i.e. hat-shaped, punch, and double-notch. This research will conduct finite element analysis to study the effect of shear angle on three methods of SHSB. The specimen material used in this research is 6061-T651 Aluminum which is strain rate independent. The constitutive material uses Simplified Johnson-Cook model which is approached with curve fitting to tensile test results. Then, the constitutive material obtained is ?=[360.23+802.62 ????0.923][1+(1.00 ×10?8)ln??????]. The finite element study has been conducted using Abaqus and have been compared to an experimental result to ensure its validity. The finite element analysis varied on the shear angle for circular hat-shaped, flat hat-shaped, punch, and double-notch. By comparing the true shear stress-true shear strain curves and the other results, the effects of shear angle can be seen. Using selection criteria, the potential dimension can be determined, especially in the shear angle. The stress composition in the center of shear line also discussed to know the ratio of shear stress to normal stress. The effects of shear angle which can be summarize that if the shear angle increase, then: (a) the variation of true shear stress increase, (b) the average percentages of discrepancy between ???????????? and ???????????? (?????????????) tends to increase, (c) the strain rate gradient tends decrease, and (d) the impurity of shear load increase, etc. The potential shear angle for further study is 5o. The proposed method for SHSB is hat-shaped methods.