A practical note for SHPB test with new algorithms for delimiting pulses

Data processing in split Hopkinson pressure bar technique is known to be sensitive to limits and durations of the incident, reflected and transmitted strain pulses. The dynamic stress-strain curves were found to be affected by dispersion and shifting of elastic strain pulses traveling the elastic bars. In this study, a practical note was given for split Hopkinson pressure bar test with describing new iterative algorithms that we developed for delimiting SHPB strain pulses. The developed algorithms were validated through typical in-plane dynamic compressive loading tests on [±55°]₂₀ E-Glass/Epoxy aged laminates tested in the range of 560-1025s^-1. Representative stress-strain curves were reported in this paper. The strain rate was found to be linearly pressure dependent. The dynamic modulus was found to be strain rate dependent however there was a threshold effect for the ultimate strength and strain at ultimate strength. Failure mechanisms were characterized through optical and scanning microscopy. Data for dynamic properties were fitted in empirical models.