Optimizing the Wire Diameter Distribution of a Solid Stabilizer Bar

Abstract

Stabilizer bars for automotive suspension systems are generally manufactured by bending either a rod with constant wire diameter (WD) or a pipe with constant outside diameter and constant thickness. This type of stabilizer bar contains portions that do not contribute to roll stiffness, or portions whose stress is much lower than the peak. Such portions may be redundant, and therefore unnecessarily increase stabilizer bar weight. Ideas for varying wire diameter distribution and reducing weight already exist, and tubular stabilizer bars have been commercialized with varied WD distribution. However, to the author’s knowledge, “optimizing” WD distribution for weight reduction or stress reduction research could not be found.
In this study, the WD distribution for solid stabilizer bars is optimized such that 1) weight is minimized, 2) maximum principal stress is minimized, and 3) maximum shear stress is minimized. By optimizing the WD distribution for a simple U-shape solid stabilizer bar, weight is reduced by as much as 14%, and maximum principal stress and maximum shear stress are reduced by approximately 30% and 13%, respectively. It has been determined that weight reduction is achieved by flattening the “contribution to eye deflection” for each small portion throughout the stabilizer bar. On the other hand, stress reduction can be achieved by reducing the WD for areas of low stress and increasing the WD for areas of high stress. By combining the weight optimization method and the stress optimization method, it is possible to design “a lightest stabilizer bar given a certain stress limit.”