Investigation on Dynamic Behavior of a Porous FGM Sandwich Doubly Curved Plate under Multiple Blast Loads

Porous functional gradient material (FGM) sandwich structures are widely used in various fields. However, the study of their dynamic response under multiple blast excitations is lacking. This paper develops a nonlinear dynamic model of a porous FGM sandwich hyperbolic panel based on Winkler-Pasternak elastic foundation and von Kármán strain-displacement relations. The model comprehensively incorporates the effect of material inhomogeneity, geometric nonlinearity, and time-varying blast loading for the first time. Subsequently, a numerical solution strategy is constructed by coupling the finite difference method in the spatial domain with the Newmark method in the time domain. In addition, the effects of porosity distribution, geometric parameters, foundation stiffness, and blast load parameters on the structural response frequency, deflection amplitude, and damping performance are investigated. Results reveal that sandwich panels with uniformly distributed porosity in the FGM exhibit superior dynamic stability and blast resistance under repeated explosive loads. The findings can provide theoretical support and engineering guidance for the blast-resistant design and intelligent optimization of novel porous FGM sandwich composite structures.