A multi-objective optimisation of a stiffened GFRP sandwich panel with a bilayer core structure, through finite element analysis

Abstract

Glass fibre reinforced polymer (GFRP) sandwich panels, known for their high strength-to-weight ratio, are increasingly utilized in weight-sensitive civil engineering applications. This dissertation focused on optimizing a stiffened, bilayer GFRP sandwich panel as a monolithic slab within domestic environments. This study examined how variations in facesheet thickness, core thickness, and stiffener angle (input variables) impacted vertical deflection, panel mass, material cost (output variables), and Von Mises stresses. A preliminary design of the GFRP sandwich panel, based on literature, was analysed through finite element analysis (FEA) on ANSYS Workbench. A parametric model with 432 different configurations was set up. The effects of the input and output variables were globally analysed using a Design of Experiment (DOE) function followed by a Response Surface function, and locally analysed through FEA applied to specific configurations. The optimal panel design was derived using a non-dominated sorting algorithm, parameter-related constraints, and trends observed from this dissertation. The results showed that higher panel mass and material cost reduced vertical deflection. Increasing core thickness was more effective than facesheet thickness in minimizing vertical deflection, panel mass, and material cost. Varying stiffener angles had minimal impact on the output variables. Increasing the core and facesheet thickness, respectively, globally reduced stress levels. Non-orthogonal stiffener angles shifted the stress distribution: reducing stress in the core, increasing it in the stiffening system, and maintaining it in the facesheets. The optimal panel, chosen based on the described trends from the non-dominated solutions with deflections under 8.33 mm, featured 100 mm core, 1.2 mm facesheet, and a 50o (or by symmetry, 130o) stiffener angle