Design of composite seat post for cycle-ball bicycle frame

The aim of the work was to design a laminated carbon-epoxy seat post for cycle-ball bicycle frame. It was double curved tube with circle-elliptical transition with special geometry of each end. The tube was analyzed with the use of finite element method and the values of number of parameters were optimized. These parameters were coordinates of boundaries of tube sections with different number of layers, number of layer pairs in each section and fiber orientation in the layers. Each pair of layers has plus-minus fiber orientation. So-called pareto optimization was performed with two output parameters, the weight of the tube and maximum failure index throughout the whole tube calculated with the use of Puck’s criterion.