A novel active hydroforming & curing process to manufacture GLARE laminates: Numerical and experimental investigations

Fiber Metal Laminates (FMLs) are preferable thin-walled structures in several fields for their exceptional mechanical properties. However, how to manufacture thin-walled FMLs structures with complex shapes and guarantee the high mechanical properties is still a challenge. To address these, this paper proposes an innovative hybrid forming method, referred to as active warm hydroforming and curing, to enhance the formability and performance of FMLs in GLARE form by combining the forming and curing process into a single step. The hybrid method was verified on a box-shaped part as a proof-of-concept to assess the feasibility and parameter influence. Online curing was utilized to enhance efficiency and quality. The outcomes revealed that the new method increases the ultimate tensile stress by 12.1 % and reduces curing deformation from 3.1 mm to 1.3 mm compared to the vacuum bagging method. Furthermore, the critical parameters in forming of thin-walled structures, including blank holder force (BHF), pressure rate (PR), maximum pressure (MP), and forming temperature (FT), were identified using experimental, mathematical, and numerical approaches. Four defects in the formed thin-walled structures were observed and successfully eliminated through the control of these parameters. The method and results presented in this paper also provide direct guidance for optimizing the process parameters of FMLs warm hydroforming.