Experimental and numerical formability investigation of FML sheets with glass fiber reinforced core

In this study, the formability of the FML (fiber metal laminate) sheets has been investigated by experimental and numerical methods. The sheets consist of an aluminum skin and a glass fiber reinforced core. Uniaxial tensile and stretch forming tests were performed to extract the forming limit diagram (FLD), experimentally. M-K (Marciniak-Kuczynski) method was implemented to extracting the FLD of the FMLs, numerically. The effect of skin and core thicknesses on formability was studied in variable and constant total thickness by numerical method. Finally, it has been cleared that the numerical model predicts the necking strains with less than 9% error. Also, it has been concluded that with doubling of core thickness in constant and variable total thickness, the average formability improves 15 and 23%, respectively, and with tripling core thickness, these values reach to 26 and 53%. In addition, with twofold increase of skin thickness in constant core thickness, the average formability enhances up to 76%.