Study on influence of capsule shape on nonlinear stiffness characteristics of air spring

Based on the study of the mechanics features of air spring including the nonlinearities in material, geometry, contact, the nonlinear finite element analysis was applied to study nonlinearity characteristic of air spring. The three-dimensional finite element model of a cystiform air spring was established with the method of nonlinear finite element analysis. The analytical results were confirmed by the experiment with the use of an air spring test bench. On this basis, influence of capsule shape on the elastic characteristics of air springs was studied. The results show that load capacity and stiffness of air spring increase with increasing inflation pressure, and show non-linear characteristics. Capsule shape on the elastic characteristics of air springs has significant impact. Load capacity of air spring increases with an increase in capsule radian, but its stiffness decreases.