Dynamic characterization of elastomer buffer under impact loading by low-velocity drop test method

Abstract

Abstract An approach is proposed to establish a discrete model to characterize the dynamic behavior of a thermoplastic polyurethane elastomer buffer under impact loading. To this end, a series of low velocity drop tests with initial impact velocities 1.77–4 m/s was carried out. The impact force versus time histories for the samples under impact loading were measured with varying initial impact velocities. To obtain acceleration, velocity and displacement of the projectile, Newton's second law of motion and the numerical integration method were applied. The stress-strain, coefficient of restitution, loss factor and dissipated energy of samples were determined. Following, the experimental data were used to establish a mathematical model for the elastomer buffer. To reach this aim, Maxwell and Kelvin-Voigt viscoelastic impact models and one-dimensional viscoelastic free decay oscillation model were employed. It was observed that Kelvin-Voigt and one-dimensional viscoelastic free decay oscillation models underestimated the buffer dynamic characteristics. An approach was proposed to calculate the calibrated nonlinear Maxwell viscoelastic impact model. The proposed model consists of a nonlinear dashpot and nonlinear spring. The calibrated nonlinear Maxwell model predicted the elastomer buffer impact behavior in terms of peak force, maximum deflection, dissipated energy and coefficient of restitution with high accuracy.