title: Experimental and numerical investigations on the use of polymer Hopkinson pressure bars.
abstract: Split Hopkinson pressure bar (SHPB) testing has traditionally been carried out using metal bars. For testing low stiffness materials such as rubbers or low strength materials such as low density cellular solids considered primarily herein, there are many advantages to replacing the metal bars with polymer bars. An investigation of a number of aspects associated with the accuracy of SHPB testing of these materials is reported. Test data are used to provide qualitative comparisons of accuracy using different bar materials and wave-separation techniques. Sample results from SHPB tests are provided for balsa, Rohacell foam and hydroxyl-terminated polybutadiene. The techniques used are verified by finite-element (FE) analysis. Experimentally, the material properties of the bars are determined from impact tests in the form of a complex elastic modulus without curve fitting to a rheological model. For the simulations, a rheological model is used to define the bar properties by curve fitting to the experimentally derived properties. Wave propagation in a polymer bar owing to axial impact of a steel bearing ball is simulated. The results indicate that the strain histories can be used to determine accurately the viscoelastic properties of polymer bars. An FE model of the full viscoelastic SHPB set-up is then used to simulate tests on hyperelastic materials.
authors: School of Engineering, University of Aberdeen, Fraser Noble Building, King's College, Aberdeen AB24 3UE, UK j.harrigan@abdn.ac.uk.
authors: John J
authors: JJ
authors: Harrigan
authors: School of Engineering, University of Aberdeen, Fraser Noble Building, King's College, Aberdeen AB24 3UE, UK.
authors: Bright
authors: B
authors: Ahonsi
authors: School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Pariser Building, Sackville Street, Manchester M13 9PL, UK.
authors: Elisavet
authors: E
authors: Palamidi
authors: School of Engineering, University of Aberdeen, Fraser Noble Building, King's College, Aberdeen AB24 3UE, UK.
authors: Steve R
authors: SR
authors: Reid
keywords: Hopkinson pressure bar; finite element; stress wave; viscoelasticity