Multiobjective optimization of perforated square CFRP tubes for crashworthiness

Open holes and cutouts have been widely used in composite structures for various engineering purposes. However, perforation could largely alter the structural responses and crashing behavior, thereby creating significant challenge in composite design. This study carried out a parametric study and design optimization on the perforation parameters for the perforated carbon fiber reinforced plastic (CFRP) square tubes to improve the structural crashworthiness. First, a finite element model was established for perforated square tube through experimental validation. Second, the support vector regression (SVR) surrogate models of the crashworthiness indices were established with respect to the perforation design variables following a parametric study. It was found that the radius of the hole had the most significant effect on crashworthiness performance of the CFRP tube, followed by the height-to-length ratio and the offset-to-width ratio of the hole. Finally, the multiobjective optimization was performed to optimize the perforated parameters by integrating the surrogate modeling technique and multiobjective grey wolf optimizer (MOGWO). The optimal design enabled to enhance 100.47% in the specific energy absorption (SEA) (specifically from 29.61 J/g to 59.36 J/g) only with a minor sacrifice of 4.62% in the first peak load (F-max) (from 81.22 kN to 84.97 kN).