Available at: https://digitalcommons.calpoly.edu/theses/3101
Date of Award
6-2025
Degree Name
MS in Mechanical Engineering
Department/Program
Mechanical Engineering
College
College of Engineering
Advisor
Ramanan Sritharan
Advisor Department
Mechanical Engineering
Advisor College
College of Engineering
Abstract
The design of full-suspension mountain bikes is a careful balance of suspension kinematics, structural dynamics, and manufacturing optimization for the expected use case. A bike designed to excel in one area will likely exhibit reduced performance in others. This optimization problem is addressed by designing, integrating, and testing a dual-rate spring system within a fully custom frame. The dual-rate spring is fully decoupled from the rest of the suspension kinematics, providing designers with an additional parameter to achieve ideal suspension behavior. This is accomplished by placing a thermoplastic polyurethane (TPU) bushing in series with the rear shock. The influence of this bushing is limited to the first 30% of suspension travel by use of bump stops. The design and manufacturing of the test platform are covered. The viscoelastic behavior of the TPU bushing is analyzed and its effects on the vibratory response of the theoretical system is studied. Testing methodology is covered, and frequency analysis is used to determine the efficacy of the design.