Design and Optimization through Finite Element Analyses of a Recumbent Racing Bicycle for the World Human Powered Speed Challenge

The aim of this paper is to design a new recumbent bicycle frame for the World Human Powered Speed Challenge (WHPSC) through analyses and optimizations which are conducted with the finite element solver Optistruct. The goal of the WHPSC is to set a new land speed record for vehicles that rely on human power alone. The frame proposed in this thesis will be completely new and will have the objective of halving the mass and increasing the stiffness compared to a previous frame (Taurus by the Team Policumbent), yet using the same type of carbon fibers and the same fiber volume fraction of the composite material as in that prototype. The new frame proposal has been designed to satisfy manufacturing constraints and also to be compatible with an already existing aerodynamic fairing, for which new attaching elements have been created. Moreover, in the new frame proposal an upgrade for the transmission has been developed, which improves the stability of the bicycle. The paper starts with the complete examination of the previous frame model Taurus in order to indentify the objectives of the new frame. This is followed by the design process of the new frame, which is divided into several stages. Each stage has a specific focus and is conducted with the help of a topology optimization, a free-size optimization, a size optimization and a shuffle optimization analysis. The designer has had the task of creating the FE models, setting up the analyses and, at the end of each optimization, having to interpret and to re-elaborate the results obtained. Finally, the achievement of the objectives stated above has been verified by subjecting the new frame to the same static analyses used to calculate the stiffness of the Taurus frame.