Effect Of Multi Notched Parameters Of Round Magnetic Hysteresis Alloy Bar On Fatigue Property

With the continuous development of science and technology, a large number of new magnetic functional materials as the core components are widely used in modern high-tech fields. As these kinds of materials are often worked in the electromagnetic environment, the problem that the electromagnetic field has an effect on the mechanical load which cannot be ignored. So whether the materials can work safe and stable become to the topic of concern gradually. Previous research on the anti-fatigue design was mainly involved in mechanical load under the action of fatigue analysis. But for magnetic materials, the traditional fatigue analysis method will produce error, because the magnetostriction occurred under magnetic field, which will change the stress and strain under mechanical load. So. in order to lay the foundation for the research of magnetic material fatigue characteristics, there is necessary to find a suitable method for the magnetic materials.This paper got a systematic study on the fatigue characteristics of multi-notched check bar of the magnetic hysteresis alloy. The finite element model of V-shaped notch check bar was established under the radial magnetic field and axial load. The stress and strain near the tip of notch was analyzed by ANASY, and the maximum actual stress and strain was revised by the formula of magnetostriction. The Stress Concentration Factor K, was calculated and the fatigue life was obtained. And then The finite element models of double notches check bars and triple notches check bars were established based on the V-shaped notch check bar. The K, and fatigue life of each check bar were calculated. Combined with the experimental results, the research was carried out as follows.1. Effect of multi notched parameters on K, under uniform radial magnetic field.The level of stress concentration near the tip of V shaped notch fell down by the increased notches. and it was also controlled by the parameters of the increased notches. The level of stress concentration became weak by reducing the distance between the new-increased notch and the original one. The increase of radius p and notch opening angle a were helpful to lower down the stress concentration. The K, got a minor level when the notch depth h of the increased notch was close to the depth of the original one. especially for triple notched models. When the ratio of h of the increased notches to h of original one was9to10. the Kl achieved the minimum. 2. Effect of multi notched parameters on fatigue life of multi notched bar under uniform radial magnetic field.The fatigue life was calculated by the method of Local Stress and Strain. The relationship between multi notched parameters and fatigue life was established. The result suggested that the distance d of each notch had an impact on fatigue life of lg(2N) exactly, the closer the d was, the longer life the model had. What’s more, the parameter h also had influence on the fatigue life, but p and a had quite a little effect on the fatigue life.