Fatigue characterisation of thin steel sheets is often prone to a large amount of scatter in the observed lifetime. It has been found that microstructure-induced lifetime variance can be caused by the local elastic and plastic inhomogeneity of neighbouring grains. in other words, the material properties can vary between adjacent grains near the material surface, thereby influencing the fatigue crack initiation and propagation mechanism. The main objective is understanding the effects of microstructure randomness on the fatigue fracture of electrical steel. A finite element modelling approach is proposed that includes randomly generated shapes and sizes of grains with different elasto-plastic material behaviour. Multiple simulations are used to explore the influence of randomness in the material properties considering the distributed elastic modulus and local strain hardening at a microstructural level. Complementary, the impact on variance in fatigue life prediction is investigated by using a critical plane approach.
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