Stress Analysis of the Coil Springs with Arbitrary Cross Section

Many studies have been caried out for the stress problem of coil springs by many investigators. Few analysis, however, have been performed for the coil springs using the wire of noncircular nor rectangupar cross section except the egg shaped cross section for which the simplified design formulas are proposed by H. O. Fuchs. Concerning the analytical methods for the spring with the wire of arbitrary cross section, the conformal mapping method and the finite element method are available. But the former is difficult in determining the mapping function for the arbitrary cross section and the latter is costly for its use of large computers and FEM programs. In this paper, the ‘Fourier expansion collocation method’ are presented and the analytical results are compared with the experimental ones. It is clarified that the stress analysis of the coil springs with arbitrary wire cross section can be carried out by the new method with sufficient accuracy for practical use.