Numerical investigation on multi-layer RC sandwich panels with helical springs under free air blast loads

It is crucial for underground structures, whether civilian or military, to have lightweight protective layers that can withstand significant and repeated blast pressures. Reinforced concrete sandwich panels are commonly used to protect these structures. The core of the sandwich panel is designed to reduce the blast energy that reaches the back panel, while the front face is built to absorb and reflect the blast load. Using ANSYS AUTODYN, the dynamic response of the proposed reinforced concrete sandwich panels under free air blast loads is investigated numerically. These panels contain multi-layers of helical springs to enhance the blast resistance. Based on the experimental data in (Abdelsalam, M. 2019) [1], the model of RC panel-helical springs-RC panel (RHR) sandwich panel is validated first. Then, A developed sandwich panel named the RHSHR sandwich panel is investigated. This sandwich panel consists of an RC Panel-Helical Springs-5 mm Steel Plate-Helical Springs-RC Panel, According to the findings, the improved sandwich panel can decrease the front RC panel’s maximum displacement by about 25% when compared with that of the RHR sandwich panel. Additionally, it is observed that the existence of the multi layer helps in reducing the damage level of the sandwich panel’s back RC panel. Finally, a detailed comprehensive parametric study is conducted by changing the overall stiffness of the interlayer at different scaled distances, which provides guidelines to design the proposed sandwich panel.