Study on In-Plane Compressive Buckling Behavior and Parameter Optimization of PMMA-Based Thermoplastic Sandwich Structures

Thermosetting epoxy resins commonly used in wind turbine blades pose significant recycling challenges. This study addresses this limitation by using an eco-friendly, recyclable liquid polymethyl methacrylate (PMMA) resin to fabricate thermoplastic sandwich panels and by investigating their in-plane compressive buckling behavior. The experimental results demonstrated that the proposed PMMA thermoplastic sandwich panels exhibited improved in-plane compressive performance, with a 5.22% higher ultimate load than traditional epoxy counterparts. Furthermore, to investigate the effect of groove configuration on the buckling stability of composite sandwich panels, a finite element (FE) model for PMMA sandwich panels with initial geometric imperfections was established in this paper, and the reliability of the FE model was validated via compression and buckling tests. Finally, a Kriging surrogate model coupled with the NSGA-II algorithm was adopted to carry out multi-objective optimization, with groove parameters set as design variables. Based on the FE verification results, the optimized configuration (Point A) reduced the structural mass by 2.24%, while increasing the critical buckling load and shear modulus by 5.71% and 10.27%, respectively. Research on the buckling performance and groove configurations of PMMA sandwich panels, which can be applied to wind turbine blade webs and airfoils, can provide crucial data support for the engineering application of sustainable PMMA-based large-scale wind turbine blades.