A comparative study on energy-based fatigue criteria for lifetime calculation of magnetorheological elastomers under multiaxial loading

Predicting fatigue life of magnetorheological elastomers (MREs) containing, different volumes of carbonyl iron particles (CIPs) with various external magnetic fields has been investigated. Unlike many studies on fatigue behavior of MREs, representing experimental models, a novel three-dimensional constitutive magneto-hyper-viscoelastic semi-coupling model based on strain energy density function (3DSED) is derived, analyzing the fatigue of structures enhanced by MRE experimentally and numerically. In this 3DSED model, to obtain the best predicting MREs’ fatigue life, three different hyper-elastic functions, including Neo-Hookean, Mooney-Rivlin, and Yeoh are utilized. Using some uniaxial compression, such as loading phase, relaxation, and loading/unloading phases tests, hyper-elastic, magneto-elastic, and viscoelastic constants are determined. In addition, multi-axial fatigue tests are performed to define the number of cycles to failure. These tests have been induced by the magnetic fields of 0, 0.27, and 0.4 T. The fatigue tests re-performed with the magnetic field of 0.3 T to compare the predicted results using the proposed fatigue models. The results show that the 3DSED model can be used for the prediction of MREs fatigue life when subjected to complex and repetitive loading. For all CIP contents, the Mooney-Rivlin fatigue predictor has more accurate results. The Yeoh fatigue predictor indicates better results for MREs with higher CIP contents, while the Neo-Hookean fatigue predictor doesn’t show acceptable results for any CIP contents.