Mechanical behavior of a glass fiber-reinforced polymer sandwich panel with through-thickness fiber insertions

•For first time, mechanical behavior of GFRP panels is computed directly as a function of their constituents.•A set of experiments is performed on constituents of the GFRP sandwich panels: skin and fiber insertion.•The resulting constitutive relationships are used in a nonlinear finite element model.•The models can predict the behavior of GFRP sandwich panels beyond their elastic limits.•A parametric study is performed to optimize the effects of skin and panel thickness, and fiber pattern. Fiber Reinforced Polymer (FRP) sandwich panels have been commonly used in aerospace, marine and transportation applications. Their lightweight, high strength and superior durable characteristics make them a strong candidate for the construction industry. In specific applications, the core material between the FRP skins of the sandwich panels provides insulating properties that are beneficial for building applications. The panels used in this study are composed of Glass Fiber Reinforced Polymer (GFRP) skin layers, glass fiber insertions and a foam core. This paper presents the results of a computational and experimental study on the mechanical behavior of a 3-dimensional GFRP sandwich panel with through thickness fiber insertions. Samples of the GFRP skin and glass fiber insertions were cut out from larger panels and are tested to determine basic material properties of the components of the sandwich panels. The experimental results on the components were used to create a nonlinear finite element model that can predict the large-scale mechanical deformation of the sandwich panels. The model can predict force–displacement behavior of the panel accurately under a variety of experimental conditions. The finite element model was used to determine the bending capacity of sandwich panels of various span lengths to create load tables for design engineers. This model is further used to predict the mechanical performance and failure load of sandwich panels for specific load conditions. A parametric study was also performed to determine the correlation between the density and pattern of fiber insertions on panel behavior. The results show that increasing the density of fiber insertions makes the panel stiffer. An alternating pattern for the insertions also increased the overall panel stiffness. Varying the overall panel thickness between a minimum and a maximum thickness indicted that an optimal overall thickness could be established. The results of the parametric study agreed with