Vehicle safety has increasingly become an economical factor for vehicle manufacturers and this has become most apparent in car safety [1-4]. Manufacturers are now spending considerable resources on safety research. Government requirements on safety have compelled manufacturers to carry out considerable number of crash tests to validate the safety of their cars [6-7]. The data from these tests is important in the development of simulation models employing finite element (FE) software. Many companies predict crashworthiness using commercially available software such as PAMCARSH and LS-DYNA. These simulations are based on mathematical constitutive equations and hence any simulation created is only as representative as the constitutive equations used. This project has studied the reliability of the material models used by LS-DYNA. Material models selected for analysis are used extensively by impact simulations software and were namely: Power Law Plasticity and Cowper/Symonds. Piecewise Linear Plasticity was also selected because it is based on a true stress/strain and is expected that the simulation would be representative. The models were developed using Belytschko-Lin-Tsay shell elements and were compared with experimental tests employing uni-axial tension strips carried out on three materials – aluminium, high strength steel and mild steel. The tests were carried out using a DARTEC tensile testing machine (up to strain rate of 2.0s-1) at UCE in Birmingham. Testing for the higher strain rates (aluminium up to 269.1s-1, mild steel up to 460s-1, and high strength steel up to 456.9s-1), were carried out at The Royal Military College, Shrivenham using a ROSAND tester.