Exploring the formability of GLARE laminates enhanced with hybrid nanofillers through formability index, anisotropy, and surface crack length analysis

The present study highlights the formability of hybrid nanofiller modified Glass Reinforced Laminate (GLARE) laminate, by considering the formability index, anisotropic characteristics, and surface crack length, which represent the considerations of forming capability, inherent material property, and damage tolerance, respectively. The GLARE laminates were manufactured by using hybrid fillers, multi-walled carbon nanotube/nanoclay (MWCNT/NC), and multi-walled carbon nanotube/Mg-Al layered double hydroxide (MWCNT/Mg-Al LDH). The formability analysis was carried out through the results of tensile test and Erichsen cupping test. The anisotropy of the laminate was accounted by considering the parameters, normal anisotropy, and planar anisotropy. The microscopic analysis was performed after the formability test to measure the surface crack length to interpret the forming response of the laminate with hybrid fillers. Desirability function approach (DFA) was applied to prioritize the laminates against the formability index, the anisotropy characteristics, and surface crack length. The results showed that the GLARE laminates with single filler are more suitable for forming operations than the laminates with hybrid fillers. The nanofillers with mixed morphology induced brittleness in the binder. Among the laminates with hybrid fillers, the combination of MWCNT/Mg-Al LDH exhibited improved compliance with the forming operation. Nanofillers modified adhesives used in the fabrication of GLARE laminates proved to enhance the mechanical properties of laminates. The results of the present study showed an insight into the formability of the laminate. The understanding about the formability of GLARE laminate enables the designer to design automotive and aircraft lightweight structures.