Abstract In this study, a new general nonlinear magneto-elastic coupled constitutive model was proposed for soft ferromagnetic materials under magnetic field and pre-stress. The model is based on thermodynamic theory of magnetic materials and Jiles theory on magnetomechanical effect, considering demagnetization field. This model can accurately predict the changes of magnetostrictive strain and magnetization under pre-stress; in particular, it can obviously predict the nonlinear change of magnetostrictive strain according to compressive pre-stress. In addition, this model is concise by not including the inverse function of magnetization relationship and the piecewise function of stress in its mathematical form and can be degenerated to the previous general constitutive model for giant magnetostrictive materials. The prediction result by this model is well-consistent with experimental data. In comparison with the existing constitutive models for soft ferromagnetic materials, this model was demonstrated to have obviously-improved prediction accuracy, particularly in the compressive state. In conclusion, the proposed model can fully describe the effect of pre-stress on magnetostrictive strain and magnetization and the effects of magnetic field and pre-stress on Young’s modulus and relative magnetic permeability, reflecting the effect of demagnetization field on magnetomechanical characteristics.

中文翻译：

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软铁磁材料的一般非线性磁弹性耦合本构模型

摘要 在本研究中，针对磁场和预应力作用下的软铁磁材料，提出了一种新的通用非线性磁弹性耦合本构模型。该模型基于磁性材料的热力学理论和磁力效应的 Jiles 理论，并考虑了退磁场。该模型可以准确预测预应力作用下磁致伸缩应变和磁化强度的变化；特别是，它可以明显地根据压缩预应力预测磁致伸缩应变的非线性变化。此外，该模型在数学形式中不包括磁化关系的反函数和应力的分段函数，因此简洁，可以退化为以前的巨磁致伸缩材料的一般本构模型。该模型的预测结果与实验数据吻合良好。与现有的软铁磁材料本构模型相比，该模型被证明具有明显提高的预测精度，特别是在压缩状态下。综上所述，该模型能够充分描述预应力对磁致伸缩应变和磁化强度的影响，以及磁场和预应力对杨氏模量和相对磁导率的影响，反映退磁场对磁力学特性的影响。