Material parameter identification on metal matrix composites

Abstract

Tests were done on the compressive behaviour of different metal matrix composite materials. These extremely hard engineering materials consist of ceramic particles embedded in a metal alloy binder. Due to the high stiffness and brittle nature of the material, compression tests were only performed to about 2% uniaxial strain as measured by the displacement of the hydraulic cylinder. In room temperature tests, three strain gauges are secured evenly around the centre of the test section. The results from these strain gauges indicate that some compression instability, eccentric loading or other resulting bending condition is present. In this work, a finite element inverse analysis is employed to determine not only material parameters but also the boundary conditions that best replicate the experimental data. The quality of the fits is subject to the limits of the material model and boundary parameterisation. An alternative procedure that uses the time and strain history to evolve the yield stress is also employed to approximate the material parameters. The Mechanical Threshold Stress model is used to model the materials.