Abstract: To obtain the parameters in the Fancher leaf spring model with the step method and experiments often leads to large randomness in the engineering praxis. A one-time non-linear fitting method to obtain all parameters without estimation was proposed to reduce the calculation error. The Fancher model was also discussed to deepen the understanding of the mechanism and its differential equations in the aspects of application scope and limitation. The results of simulation were compared with those of leap spring characteristic experiments showed the proposed parameter fitting method was characterized by high accuracy, being able to simulate the non-linear hysteresis characterstics of the leaf spring.

Key words: vehicle engineering, leaf spring, hysteresis characteristic, nonlinear fitting