Experimental and numerical investigation of an alternative hydroforming process of aluminum/glass fiber-reinforced polymer-based fiber metal laminates

Fiber-Metal Laminates (FMLs) have gained prominence in advanced industries due to their superior structural reliability, weight reduction, and enhanced damage tolerance. However, the formability of FMLs is constrained by the strain capacity of the fibers and the strength of the interlayer interfaces. This research aims to enhance the formability of FML sheets in hydroforming using a novel approach that combines non-uniform blank holder force (BHF) and cavity pressure (CP). This is achieved by adjusting the frictional contact between the blank holder and laminate, as well as between the liquid pressure and the lower blank surface, in relation to the punch travel. A comparison was drawn between the experimental and numerical outcomes derived from the proposed method and the conventional process. The findings underscore that this approach effectively eliminates wrinkles and ensures a uniform thickness distribution across the FML three layers. It achieves a maximum thickness reduction of 14.30% for the aluminum layers, compared to the conventional process which results in a thickness reduction of 21.56%. As a result, there is a significant 25% improvement in forming depth compared to the conventional hydroforming process, demonstrating the effectiveness of enhancing the formability of FMLs.