The analytical methods for single leaf steel springs should at least include two areas:
- (1)
allowance for any curved or tapered shape, and
- (2)
technologies to precisely predict the geometrical configuration due to large deflection.
The last item is an outstanding consideration in automotive application because of the parts alignment requirement.
In this paper, a practical analytical method is presented to achieve the goals mentioned above.
Basically, the. flexibility method of finite element was employed in the solution technique. In the spring application, this approach can save computer time because of the elimination of matrix inversion in the internal computation.
An integration form of the flexibility matrix for each element was given in this paper to allow for a tapered spring shape. This integration-formed flexibility matrix can be approximately evaluated by the Gaussian Quadrature Formula.
The nonlinear corrections between the basic deformations and grid point displacements were also described in this study. Therefore, high accuracy in the prediction of the geometrical configuration of a deformed spring is assured.
The incremental method was applied in load domain. Then, the flexibilities of elements can be computed along the load path.
The theory presented in this paper has been partially integrated with an engineering diagnostic system, and implemented in the BASIC language. Two programs. SLEAF and LLEAF were developed for transverse and the longitudinal leaf springs respectively. Both programs are now available in Analysis Department of GM cpc Engineering.