| The objective of this investigation was to determine whether a 6-inch diameter Split Hopkinson Pressure Bar (SHPB) is feasible, whether the assumptions made in a typical 2- to 3-inch SHPB still apply, and what changes, problems, and issues would be associated with an SHPB that size. The effort included a mathematical and a numerical analysis. Experimental data from a 2-inch SHPB were used to compare and validate analytical models.; A methodology based on the Pochhammer-Chree frequency equation was developed by the author to study the wave propagation and wave interaction in any size SHPB. Additionally, a second order accurate finite difference code was used to mathematically understand the wave motion in a typical bar.; The effects of friction and inertia were analyzed numerically, and general guidelines and corrections were developed.; This investigation concluded that a 6-inch SHPB is theoretically feasible and, in fact, identical to any existing system if the input pressure pulse duration is scaled appropriately.; The modified Pochhammer-Chree method can be used to assess the validity of any size SHPB and to study the wave interactions. If the specimen length and diameter are kept in the same order of magnitude, one need not worry about friction in the proposed 6-inch SHPB. A correction will be needed to account for inertia, especially at strain-rates of 50 to 100 sec{dollar}sp{lcub}-1{rcub}{dollar} and above. The Split Hopkinson Pressure Bar has been and remains a reliable, accurate, and useful tool to study material response to loading, even for a new proposed system six inches in diameter. |
