Fundamental jet performance tests of linear shaped charges (LSC) were conducted to evaluate their jet penetration. The purpose of these tests is to enhance the penetration performance of LSC. The apparatus used for these tests were based on penetration tests for conical shaped charges (CSC). Photos of the aluminum-sheathed LSC jet taken by using flash X-ray confirmed the jet velocities to be about 2,400 m/s. The velocity was also verified by the AUTODYN-2D code, and was an unexpected figure as compared to CSC. The penetration velocities of aluminum-and lead-sheathed LSC against steel plates were calculated to be less than 1,000 m/s at a maximum region.

We carried out an impact experiment in order to investigate the influence of magnetic field intensity and inner diameter of the orifice on MR fluid motion under an impact load. The experiment was conducted by measuring the piston displacement. From the piston displacement, its velocity and acceleration were calculated.

The apparent viscosity of magnetorheological (MR) fluids changes in the presence of a magnetic field. The stronger the magnetic field applied, the more the apparent viscosity increases. An increase in the apparent viscosity increases the restriction on the flow of MR fluids. In this study, we perform a qualitative analysis to investigate the effect of a magnetic field on MR fluids under an impact load. An experimental apparatus that consists of a drop-test tower was developed to simulate the impact load, and an MR fluid in a U-pipe was subjected to the impact load via a piston rod. In the experiment, we measured the displacement and velocity of the piston rod. On the basis of the results, the influence of a given magnetic field on the behavior of MR fluids under an impact load is discussed.

This study is an investigation on the effect of a chamfered orifice inlet on magnetorheological (MR) fluid subjected to shock loading. Three different orifices (without chamfer, chamfered at 60°, and chamfered at 120° on the inlet area) are used. MR fluid is subjected to shock loading, and a magnetic field is generated on the orifice area. Experiments are conducted by measuring piston displacement and damping force. Piston velocity is calculated from the piston displacement data. The results indicate that a chamfered orifice inlet affects the piston stroke, piston velocity, and damping force. The characteristics of piston velocity between the orifice without chamfer and the chamfered orifices are different. The post-peak decrease in piston velocity in the chamfered orifices is more refined than that in the orifice without chamfer. However, the chamfered shape in the orifice inlet reduces the shock loading performance of MR fluid.