ABSTRACT
ABSTRACT: The significant functional and comfort advantages of air-spring suspension systems compared to conventional suspension systems lead to an increasing application in automotive industries. The main parts of such suspension systems are the damper and a cavity, filled with compressed air dealing as a gas spring. The cavity is surrounded by a bellow, consisting of a cord-rubber composite forming a rolling lobe during service. Due to the material heterogeneity and the large deformations of the rubber matrix between the cords, the development of a new air-spring system is still a challenging process. In the present paper numerical fatigue lives are compared to experimental fatigue lives taken from the literature. The numerical analysis is based on a global to local scale analysis as described in (von Eitzen, Weltin, Flamm, & Steinweger 2015). The fatigue life based on crack nucleation is calculated via the Wöhler concept (Flamm, Steinweger, & Weltin 2003) using different damage parameters and via the concept of cracking energy density described in (Mars 2001). S-N curves are determined using simple tension test specimens and a newly developed cord-rubber specimen. Missing parameters are fitted to experimental data for better results. The influence of the diameter of the rolling lobe and the inner pressure of the gas cavity are considered in the finite element analysis and the influence of temperature is taken into account using the Arrhenius equation. The methods and results are discussed. Furthermore, the descriptions of the cord-rubber interface and their deficiencies in analysing the deformation behaviour are mentioned.
