Design and Optimization of Variable Stiffness Composite Cylinders With the Consideration of Manufacturing Interaction

In this study, a variable stiffness (VS) composite cylinder subjected to bending load is designed and optimized for maximum buckling load incorporating the effect of manufacturing defects. The VS composite cylinder is designed first based on theoretical buckling analysis. Then, the “homogenized” stiffness method is proposed to account for the effect of the gaps on material properties in a computationally efficient way. Finally, a genetic algorithm (GA) is used to obtain optimum solutions containing manufacturing interaction. The optimization results show that the buckling capacity of the VS cylinder with the consideration of manufacturing defects is 14.6% higher than its constant stiffness (CS) counterpart and reduced by 4.8% compared to the VS composite cylinder without gaps. In it, the gaps where the circumferential angle changes from 90° to 270° are thought to be the reason for the reduction of the critical buckling load of the VS cylinder considering gaps. Moreover, narrower tow width, wider course width, as well as smaller steering radius together with aspect ratio would result in higher critical buckling load. These results offer more realistic VS composite designs to improve the bending-induced buckling performance of the cylinder effectively.