Analysis of the bending behavior of RC wall subjected to impact loading

Abstract

This research studies the shear failure surface of the concrete constitutive model and the loading by load-time function and projectile modeling for simulating bending behavior of reinforced concrete (RC) wall impacted by the soft missile to verify their influences on simulation results. Flexural test of RC wall from VTT-IRIS project was selected as a target test and the effect of the shape of shear failure surface and load-time function were considered by using LS-DYNA, the commercial explicit dynamic code. The shear failure surface of one of the typically used concrete model for impact analysis, Continuous Surface Cap Model (CSCM) was examined with the material parameters which define the shape of the shear failure surface. For parametric reason, current CSCM has a limitation of analyzing the behavior of high strength concrete. However, CSCM which simulated the high strength concrete showed suitable results in case when it was loaded with low pressure invariant like the flexural test. Deformable missile based on Hughes-Liu element formulation was modeled. The deformed shape of the projectile after the impact, and the contact force-time function was obtained and discussed. Also, the effect of the shape of a load-time function was discussed by comparing the displacement results which were applied with two different load-time functions. The peak value of the load-time function, which mainly affects the maximum displacement and the load duration time, which mainly affects the residual displacement of the RC wall were considered as the dominant factors for the analysis. The simulation results using CSCM with the load-time function and projectile model were compared with the test result. Similar results with the VTT test could be obtained for maximum displacement and residual displacement, and relatively analyzing the axial strain of rebar inside the concrete was found out to be still challenging.