GENERALIZATION OF SPLIT HOPKINSON BAR TECHNIQUE TO USE VISCOELASTIC BARS

To study the high strain-rate mechanical behaviour of materials having lower wave impedance, it is suggested to generalize the split Hopkins on bar technique by using polymeric bars. The key of such a generaliza tion lies in the method for determining the stresses and particle velo cities at two interfaces of specimen from the strain pulse signals mea sured at the strain gauges located in a distance from the interface, t aking account of the dispersion and dissipation of viscoelastic wave p ropagating in polymer bars. Based on the Zhu-Wang-Tang viscoelastic co nstitutive equation and the characteristics theory of wave propagation , such a method is developed and discussed in detail. The expermental measurements confirm that in order to avoid both the quantitative and qualitative errors, neither of which are negligible, the viscoelastic wave effects must be and can satisfactorily be taken into consideratio n by the viscoelastic wave analytical method suggested in the present paper.