Flexural and sinking stiffnesses investigation of metal, glass fiber reinforced plastic and hybrid laminates through a semi‐experimental method

Abstract The hybrid metal/GFRP laminate is a kind of typical hybrid structure consisting of thin metal sheets and glass fiber reinforced plastic laminates, which combines the benefits of low cost, high strength, excellent impact resistance, and good corrosion resistance. In this work, a semi‐experimental method based on a nondestructive test and the analytic solution of the thin plate's deflection for the flexural and sinking stiffnesses identification of hybrid metal/GFRP laminates was proposed and validated by corresponding numerical simulations. Then, in total 17 different specimens (including metal, GFRP and hybrid metal/GFRP) were prepared and tested by the proposed semi‐experimental method to investigate their flexural and sinking stiffness performances in multiple perspectives (including stiffness per unit mass/volume/price/surface density). The analytic solutions show that the flexural and sinking stiffnesses are proportional to macro equivalent moduli of laminate specimens and proportional to the third power of thicknesses of specimens. The test results show that the stiffnesses per unit mass/density of the 7‐ply GFRP laminate can be comparable to those of the variable‐thickness rolled blank (VRB) made of steels, but the stiffnesses per volume/price of the 7‐ply GFRP laminate are only one fifth to one quarter of those of VRB. It is also found that though the hybrid metal/GFRP laminate with the combination sequence of aluminum plate/5‐ply GFRP/aluminum plate has the lowest GFRP layers' volume fraction, but has the best performances of stiffnesses per unit mass/density. Besides, the VRB part can significantly improve the stiffnesses per unit volume of hybrid metal/GFRP laminates.