Modeling and numerical simulation for the prediction of the fatigue strength of air springs
|Bearbeitung:||M. Sc. Niraj Kumar Jha, Prof. Dr.-Ing. Udo Nackenhorst|
|Förderung durch:||Continental Teves AG|
Fatigue failure of cord-reinforced rubber composite has been the subject of extensive studies in automotive industries due to its importance in engineering applications. The classical examples of such composites are found in tires, hoses, and airsprings. In order to assess the reliability and fatigue life of such composite structure it is important to understand the potential failure modes and mechanisms. Typical failure modes include cord breakage, cord-rubber interface debonding, delamination, matrix cracking or any combination of all these mechanisms. These failure mechanisms are regarded as a gradual sequence of damage events, e.g. microcrackings, debonding, delamination and are described as a continuous processes. In particular, to model failure in materials or structures, a constitutive description based on internal state variable (ISV) is found to be very attractive. The reason is that ISV framework incorporates thermodynamics of irreversible process and has been employed in several branches of solid mechanics.
The structure of this research work at meso-scale comprises of three core parts, it starts with the state-of-the-art review on three-dimensional progressive damage analysis (PDA) of cord-rubber composites. A phenomenological isotropic damage model has been devised for rubber, and an elasto-plastic constitutive model for thin soft interphase layer. These models are implemented in Abaqus via user subroutine (UMAT). The concluding section of the research work also attempts to recapitulate major ﬁndings and presents a novel experimental framework to validate the damage models.