Two-Way Behavior and Fatigue Performance of 3-D GFRP Sandwich Panels

Abstract

This research presents the two-way bending and fatigue behavior of an innovative 3-D glass fiber reinforced polymer (GFRP) pultruded sandwich panel. The panels consist of two GFRP face sheets separated by a foam core with through thickness GFRP fiber insertions to achieve the composite action between the top and bottom layers of the panel. The panels tested under two-way bending include six different configurations to consider the effect of number of skin plies, fiber insertion patterns, panel thicknesses, and the foam type. All panels were simply supported at the four edges, loaded by a single concentrated load at mid span, and tested subjected to a quasi-static loading condition up to failure. The parameters under consideration for testing the two-way panels were also used in a one way configuration under two fatigue loading condition. The fatigue test consists of three point flexural loading configuration in which the panel is subjected to cyclic loading for a minimum of 600,000 cycles or up to failure. The research also presents the finite element analysis (FEA) which was used to describe the behavior of the 3-D GFRP sandwich panel under the effect of the applied load used in the experimental program. The effect of the various parameters including: the aspect ratio, thickness, number of skin plies, skin strength, and insertion density were considered. The experimental results were used to calibrate the analysis and produce design guidelines for practitioners. The proposed design guidelines can be used for design of the panels for various applications such as truck trailer elements, temporary mats, and pedestrian bridge decks.