Static and dynamic analyses of insulated concrete sandwich panels using a unified non-linear finite element model

Insulated concrete sandwich panels are comprised of two outer concrete wythes and an inner layer of foam insulation. They have been increasingly used because of their advantages of light weight and energy efficiency. Various shear connectors can be used to connect the two outer concrete wythes. More recently, Fiber-Reinforced Polymer (FRP) shear connectors have been used, which can eliminate thermal bridging and improve the thermal performance. Typical approaches to Finite Element (FE) analysis treat static and dynamic analyses separately. However, due to the flexibility of the FRP shear connectors and the cracking of the concrete in insulated concrete sandwich panels, a nonlinear static analysis model would often diverge early based on a preliminary FE study conducted by the authors. To address this issue, a nonlinear explicit dynamic FE model using ABAQUS© was developed, which can study both the panels' static behavior under typical flexural loading and dynamic behavior under blast loading. Nonlinear material properties were incorporated and damaged plasticity model was used to model concrete in both compression and tension. In order to simulate the static behavior, the time loading control was applied to the FE model to slow down the rate of loading to smoothly capture the response. For dynamic analysis under blast loading, a verification study was conducted first using the developed FE model, where good correlations can be obtained between the FE and test results on a panel tested in a previous study. The FE model was further used to study the dynamic behavior of two panels under blast loading: one is a solid concrete panel and the other is an insulated concrete sandwich panel. It can be concluded that, although the insulated concrete sandwich panel is lighter, it still performs relatively well compared to the solid panel under blast loading. Therefore, it is promising to use insulated concrete sandwich panels for both conventional and blast-resistant structures.