The design and fabrication of a full-suspension bicycle using fiber-reinforced composite leaf springs and integrated viscoelastic damping

This paper documents the steps taken to produce a unique full suspension mountain bicycle. Initially, information regarding current suspension linkages as well as spring and damper combinations was collected. A kinematic model of the chosen suspension geometry was developed to obtain feasible spring rate goals for the design. A mathematical model of leaf spring displacement due to applied force was generated. A series of fiberglass and carbon fiber springs in an epoxy resin matrix were fabricated and tested for actual spring rates. Additional damping was provided by application of three varieties of a 3M structural adhesive tape with viscoelastic properties as well as Nyco's acrylic viscoelastic polymer. The construction techniques of the frame and linkage of the bicycle are also included. These are tube notching using Brittania pewter, TIG welding of cromoly steel, silver brazing, conventional machining, and CNC milling. Resulting spring rates proved to be highly nonlinear as the mathematical model predicted. However, unlike the theoretical model, the spring did not become unstable in the tested range.