Thickness Effect of Pulse Shaper on Dynamic Stress Equilibrium and Dynamic Deformation Behavior in the Polycarbonate Using SHPB Technique

The Split Hopkinson Pressure Bar(SHPB) technique with a special experimental apparatus can be used to obtain the material behaviors under high strain rate loading condition. Attempts to apply the Split Hopkison Pressure Bar in measurement on polymeric materials suffer from limitations on the maximum achievable strain and from high noise to signal ratios. This paper introduces a Split Hopkinson Pressure Bar technique, to overcome these limitations. The proposed method uses aluminum pressure bars to achieve a closer impedance match between the pressure bars and the specimen materials, thus providing both data having a low noise to signal ratio and a longer input pulse at higher maximum strain. In addition, a pulse shaper technique was used for increasing the rise time of the incident pulse to ensure stress equilibrium and homogeneous deformation in the specimen under dynamic compression. A pulse shaper is utilized to lengthen the rising time of the incident pulse to ensure stress equilibrium and homogeneous deformation of polycarbonate. The dynamic deformation behaviors of Polymeric material under compressive high strain rate are evaluated using the modified SHPB technique.