On the Effects of Tube Butting on the Structural Performance of Steel Bicycle Frames

Abstract

Abstract:Previous studies have shown how finite element analysis (FEA) can be used to support designers and frame builders in the selection of butted tubes to tune the stiffness and strength behaviour of steel bicycles. The aim of this paper was therefore to analyse the effects of tube butting on the stiffness, stress distribution and energy absorption behaviour of bicycle frames using numerical simulations. Butted tubes were shown to provide a highly effective means to decrease mass whilst producing a disproportionately small change in stress compared with a straight gauge tubeset with a maximum material condition although there was no added benefit in terms of stiffness or strain energy. Conversely, decreasing the wall thickness produced an increase in stress at the tube ends that was disproportionate to the change in mass. This work can now be extended to analyse a fuller set of butted profiles for a range of tube types.

The Steel Bicycle Project: Bringing Together Tube Manufacturers, Frame Builders, and Engineers through Sports Engineering

“…Computer simulations have been used since the 1980s [3][4][5][6] (Figure 2) and can be used to complement experimental testing to gain a fuller understanding of bicycle behaviour. Previously published work in this area has aimed to help understand how specific frames might behave under known load conditions [3][4][5][6], how the frame geometry (in the form of tube lengths and angles, and tube section profiles) can influence the stiffness of the frame or parts of the frame [3,[7][8][9], and how optimisation techniques can be used on frame geometry [7,10]. One aim in this theme is to help frame builders assess how design changes can affect the mechanical behaviour of their frame designs relative to benchmark designs, but also, in absolute terms, by validating model outputs using experimentation.…”