Experimental investigation, statistical modeling and multi-objective optimization of creep age forming of fiber metal laminates

Abstract

The experimental assessment of the creep age forming performance of fiber metal laminates was considered in this study. To this end, different fiber metal laminates with the stacking sequence of [Al/02/Al] were manufactured using aluminum alloy 6061 sheets as skins along with E-glass fiber-reinforced polypropylene and E-glass fiber-reinforced polyamide 6 as two different cores. Next, a comprehensive investigation was conducted on the impacts of two main parameters in the creep forming process, i.e. the effect of time and temperature on the spring-back properties of deformed fiber metal laminates. Initially, using the design of experiments and based on the response surface methodology, an imposed spring-back of the creep age formed fiber metal laminates was modeled and the governing linear regression equations were derived and verified. Then, to find the best combination yielding the minimum spring-back, the process inputs (time and temperature) were optimized. The results proved that with an increase in either time or temperature, the spring-backs of the two types of creep age formed fiber metal laminates decreased due to the decrease in elastic strains and the increase of creep strains. Also, to achieve a creep age formed fiber metal laminate with minimum spring-back according to multi-objective optimization in both fiber metal laminates, the most proper values of time and temperature should be taken as 6 h and approximately 160°C, respectively.