Design and experimental verification of carbon fiber/epoxy resin multi-coupling laminates with extension-twisting coupling effect

In order to reveal the mechanism of hygro-thermal stability and solve the problem of insufficient coupling effect, the design and experimental verification of carbon fiber/epoxy resin (CF/EP) multi-coupled laminates with extension-twisting coupling effect were carried out. The geometric factors of the laminates were introduced, and the conditions for hygro-thermal stability of the multi-coupled laminates with extension-twisting coupling effect were deduced. Based on these conditions, the optimal design model of multi-coupled laminates with extension-twisting coupling effect was established. Genetic algorithm-sequential quadratic program (GA-SQP) hybrid optimization algorithm was used to optimize the stacking sequence of the laminates with the maximum extension-twisting coupling effect. Based on three-dimension digital image correlation (3D-DIC), the extension-twisting coupling effect of the laminates was measured. The numerical simulation and experimental results show that the multi-coupled laminates with extension-twisting effect will not undergo curing deformation when the stacking sequences meet the conditions of hygro-thermal stability. The introduction of multi-coupling effects can significantly improve the extension-twisting coupling effect of laminates and maximum increase is over 30%.