A Coupled Eulerian–Lagrangian Framework for Tracing Dynamic Response of Polymer-Based Composite Laminates Under Close-In and Near-Field Spherical Explosions

Polymer composites are lightweight materials with superior stiffness and elastic characteristics, making them well suited for aeronautical structures under complex loading. This study investigates the dynamic response of FRP composite plates subjected to close-in and near-field spherical blasts using a Coupled Eulerian–Lagrangian (CEL) framework. Quarter-symmetric finite element models are developed to reduce computational cost while maintaining computational accuracy. Fluid–structure interaction is simulated using appropriate state equations for air and explosive media. Orthotropic, strain-rate-dependent material properties from standard literature are adopted, and a representative volume element approach is adopted to define the material direction in each ply to form laminate. The entire numerical framework for blast conditions has been validated in modules against benchmark studies, showing good agreement. Various laminated stiffener configurations are designed to evaluate the effect of bottom stiffening on blast resistance. Parametric studies examine the influence of layer numbers, stiffener thickness, and stiffener depth under close-in blast conditions. Results indicate that, for the specific cross- and angle-ply laminate configurations as investigated, for a constant laminate thickness, an increase in ply count is associated with a reduction in peak deflection. Further, within the scope of stiffener geometries as studied, variation in stiffener thickness resulted in a more pronounced reduction in blast-loaded FRP plate response than the corresponding variation in stiffener depth.