The dynamic Mullins effect: On the influence of the Mullins effect on dynamic moduli

摘要

Filled polymers which are used in various areas of engineering usually show a significant stress-softening, commonly known as Mullins effect which is pretty well investigated in the time-regime (in form of stress-strain relations). As these materials are often exposed to dynamic loads (e.g. tires, engine-mounts, etc.), it is very common to test them by using the dynamic mechanical analysis (DMA) and describe the material behaviour in the frequency domain (in terms of dynamic moduli). In this contribution, it is experimentally investigated how the Mullins effect influences the dynamic properties (storage and loss moduli) of the material and it is shown that the stress-softening is not only dependent on the maximum strain in history, but is also influenced by the rate of deformation during the preconditioning process. In the second part, a modelling approach for this phenomenon is presented while the anisotropic behaviour of the Mullins effect is considered by use of the concept of representative directions. Lastly, the contribution is closed with simulations of the experiments performed to show the capability of the model.