Characterization of material properties using strain mapping and reverse engineering

For simplicity, the material properties used in engineering analysis are often assumed to be linear elastic, Isotropic and homogeneous. These simplifications may lead to erroneous stress and failure predictions if the materials involved are highly nonlinear, anisotropic and inhomogeneous. Based on the techniques of strain mapping and reverse engineering, a simple finite-element-based method has been devised with the aim of characterizing the properties of such materials under load. The method has been implemented into the commercial finite element code ABAQUS, via its User Material Subroutine (UMAT), to allow material characterization to be performed easily. Verification of the method has been carried out using simulated examples and the results showed rapid convergence of the method with good accuracy. The method has also been applied successfully to actual mechanical testing of graphite.