Performance of steel-polymer and ceramic-polymer layered composites and concrete under high strain rate loadings.

摘要

In this thesis, experimental and numerical techniques are employed to investigate the possibility of improving the impact- and blast-resistance of composite structures. Finite element models are developed to study the dynamic response and large deformation of steel-polyurea bi-layers. A Split Hopkinson Pressure Bar (SHPB) setup is used to perform impact tests on steel-polyurea-steel sandwich structures. The SHPB experiments are simulated by FEM to explore the deformation history, failure, and fracture of these structures. Penetration tests are conducted to assess the ballistic performance of steel- and ceramic-polyurea layered composites. In addition, an approximate solution to the problem of wave propagation in cylindrical layered composites is analytically obtained. A semi-analytical method for dispersion correction of traveling waves in layered cylinders is developed and verified by FEM. The SHPB is also employed to characterize the high strain rate behavior of concrete in compression and tension. A finite element model is developed to address confusions about sample size and friction effects.