Test and Simulation Comparison using Titanium Material Models based on MAT224

Titanium plate impact tests are simulated with *MAT_224, an elasto-visco-plastic material model in LS-DYNA ® with tabulated stress versus strain curves as well as tabulated strain rate and temperature dependency. The *MAT_224 input deck is built upon a series of tensile, shear and compression tests at different strain rates and temperatures conducted on a 0.5" commercial off-the-shelf titanium plate. The input of *MAT_224 is generated so that it predicts all the material property tests conducted on this plate. The 0.5" plate titanium *MAT_224 model is later used to simulate the 0.5" plate impact tests as well as impact tests of the 0.09", 0.14" and 0.25" plates. The predictive performance of the material model for each plate, including exit velocity, failure mode and the profile of the intrusion, are evaluated using the test results. It is shown that the 0.5" plate Ti-6Al-4V *MAT_224 predicts the impact test of the 0.5" titanium plate with great accuracy. However, the predictions for the impact tests of the 0.09", 0.14" and 0.25" plates, using the same material model, are not as accurate. All of these plates meet the specification of AMS-4911, but vary in yield stress from the 0.5” plate, as well as varying between states and material direction. The 0.5 inch plate is the most isotropic and as such most suited for a Von Mises material model. The other plates are from different lots, and clearly have had different processing to produce thinner material thickness. These differences within the same specification are thought to be the cause of the larger difference between test and simulation of the other plates.