Quantifying Inter-Ply Friction and Clamping Effects via an Experimental–Numerical Framework: Advancing Non-Coherent Deformation Control of Uncured Metal–Fiber-Reinforced Polymer Laminates

Pre-stacked uncured metal-fiber-reinforced polymer (FRP) laminates, which are critical for aerospace components like double-curved fuselage panels, wing ribs, and engine nacelles, exhibit better deformation behavior than their fully cured counterparts. However, accurate process simulation requires precise material characterization and process optimization to achieve a defect-free structural design. This study focuses on two core material behaviors of uncured laminates-inter-ply friction at metal-prepreg interfaces and out-of-plane bending-and optimizes process parameters for their non-coherent deformation. Experimental tests included double-lap sliding tests (to quantify inter-ply friction) and clamped-beam bending tests (to characterize out-of-plane bending); a double-curved dome part was designed to assess the effects of the material constituent, fiber orientation, inter-ply friction, and clamping force, with validation via finite element modeling (FEM) in Abaqus software. The results indicate that the static-kinetic friction model effectively predicts inter-ply friction behavior, with numerical friction coefficient-displacement trends closely matching experimental data. Additionally, the flexural bending model showed that greater plastic deformation in metal layers increased bending force while reducing post-unloading spring-back depth. Furthermore, for non-coherent deformation, higher clamping forces improve FRP prepreg deformation and mitigate buckling, but excessive plastic deformation raises metal cracking risk. This work helps establish a combined experimental-numerical framework for the defect prediction and process optimization of complex lightweight components, which address the core needs of modern aerospace manufacturing.