Optimized Design of Structure of High-Bending-Rigidity Circular Tube

Circular tubes are widely used in daily life and manufacture under bending load. The structural parameters of a circular tube, such as its wall thickness, number and shapes of ribs, and supporting flanges, are closely related to the tube’s bending rigidity. In this study, a tube with eight ribs and a flange was optimized, in order to obtain the lowest weight, through comprehensive structural optimization. We obtained the optimal structural parameters of the tube and the influence of the structural parameters on the tube’s weight. The structural parameters of tubes with different numbers of ribs were optimized. The tube with different number of ribs had the same inner diameter, bending load, and length as the tube with eight ribs. We conducted an experiment to verify the structural optimization simulation. Different tube sizes were subsequently optimized. The optimized tube with four trapezoidal ribs and a flange reduced the weight by more than 73% while maintaining the same deformation. The weight of the optimized tube with a flange reached a stable value after four trapezoidal ribs were added. When the number of ribs was two, the weight was the largest. The analysis results were consistent with the numerical results. A new AWATR (appropriate width and thickness of ribs can improve the bending rigidity of the tubes) formula was proposed, which can effectively improve the bending rigidity of tubes. Different shapes of tubes were optimized and compared. The optimized tube with four trapezoidal ribs and a flange was the lightest and easy to manufacture.