Customized Design And Biomechanics Analysis For High-end Bicycle Saddle

As one of the key parts in bicycle assembly, the saddle shape, structure and material have close relationship with comfort and injury to the cyclists. During riding, the largest deformation region on saddle is ischial tuberosity. With a long time of oppression, numbness and ischemia may cause on buttocks and even dysfunction may occur on reproductive system. To solve the above problems, a customized saddle surface design and dynamic mechanical analysis methods are proposed. Main research contents and innovative work are as follows:Firstly, through the analysis on the body shape, gender, weight, riding posture, road conditions of different cyclists, the customized saddle design requirements are concluded and its basic structure is given. Then a customized saddle design method is presented. According to the cyclist individual information and cubic B-spline theory, a parametric modeling method of saddle surface is put forward and the overall saddle surface design is realized. To get an ideal surface, a feature point positions calculation method is proposed to calculate the feature point positions; then, through the mapping relationship of the corresponding feature points, radial basis function(RBF) is adopted to adjust the saddle surface. After this, the final model of customized saddle is obtained. Finite element analysis(FEA) is carried out on this saddle and common bicycle saddle respectively. The results show that customized saddle can minimize the anterior perineum and ischial tuberosity pressure effectively. Then a dynamic modeling method is presented. Based on the principle of dynamics, the bicycle is simplified to 2 degrees of freedom system, and the dynamic model is established. Analyzing the movement process of bicycle, the basic rule of the rider movement as well as the external load is studied. First of all, based on the theory of human biomechanics, human body model is established, and static force from the saddle to the human body is obtained; Secondly based on the theorem of conservation of energy, bicycle- road model is established, and the pedal force of rider is obtained; Then according to the Lagrange theorem, cyclist- saddle model is established, and the force from saddle to rider is obtained; Finally, on the basis of dynamics, bicycle- road roughness model is established, and the impact force from saddle to rider is obtained. And then according to the dynamical model, the force is loaded in dynamical finite element. Dynamical finite element analysis(FEA) is carried out on the force of anterior perineum and ischial tuberosity pressure, the results show that the saddle force distributions are mainly on the area of anterior perineum and ischial tuberosity, and the force to cyclist can be reduced by changing the saddle structure. Focus on the pressure of the anterior perineum and ischial tuberosity, and based on the results of dynamical finite element analysis, influence parameters of riding comfort are concluded. Then using the method of orthogonal experiment,these parameters are optimized to improve the riding comfort. Finally, for convenience of application, and on the basis of the above key technologies, taking the HOOPS and ACIS as the figure development platform, and the VC++ as the development environment, customized saddle design software is developed to improve the design efficiency of customized saddle, then the design cases are shown.The above research contents and innovative work lay a technique foundation for design and analysis of customized saddle, and also lay a technique foundation for high-end bicycle customization.