Abstract
In order to make clear the mechanical properties of FRP bicycles, a study was carried out and some of the experimental data connected with the trial manufacture of FRP bicycles are presented.
This report consists of two sections, one dealing with the investigation on a Bowden FRP bicycle, and the other with the trial manufacturing study of our FRP bicycle. The Bowden bicycle did not show any excellent mechanical strength nor smooth handling stability. At the beginning of the trial manufacturing of our FRP bicycle, the study on the proper selection of basic glass material was made bused on the results of the mechanical strength tests (tensile and bending tests) on various materials. The combination of SLS-213 (satin) 2 ply and CM 305 (chop strand mat) 1 ply was found to be the best material for FRP bicycle. The resin used in this experiment was an unsaturated Polyester resin. In order to reduce the assembly cost, the following points were taken into consideration during the design of frame.
(1) The frame body, rear mudgard and chain case were integrated into one unit.
(2) The left and the right half FRP shells were joined at the center line of the frame by Epoxy resin.
(3) The principal parts of FRP shell frame were reinforced with mild steel plates.
(4) At the head and hanger portions of the frame, steel pipes were attached to the FRP shell so as to secure the smooth rotation of ball bearings.
As regards the strength of the trial manufactured bicycle, the statical load test, the bending test and the vibration test were conducted. It was apparent that the mechanical strength of the present FRP bicycle was superior in comparison with an ordinary steel-made bicycle. Also there was no defects observed on the 1040km road running test.
