Principles of design optimization for springs

Abstract

The spring is the widespread resilient element which is used in the industrial machinery and automotive systems, as diesel fuel pumps, valvetrains, brakes, suspensions, seats, doors and control elements. For reducing impact events in some heavy trucks and railroad cars primarily, helical, or coil, springs are applied. In some vehicles torsion bars are used instead of the coil springs. The reduction of weight of the suspension springs causes the decrease of unsprung mass of the axle and has a positive influence on the comfort, traction and steering properties of the car. The development of modern passenger cars has highlighted a trend towards reduced package space for suspension components in order to maximize package space for occupants and loads. Such requirements lead to reduction in spring dimensions and wire cross-section. Springs can be found in high-precision testing devices, where springs play the role of energy harvesters. The efficient design procedures for spring elements are based on the modern simulation and optimization methods. The design formulas for linear helical springs with an inconstant wire diameter and with a variable mean diameter of spring are presented. Based on these formulas the optimization of spring for given spring rate and strength of the wire is per-formed.