Modeling of Ferromagnetic Shape Memory Alloy Composite Material and Application to Magnetic Drive Actuator

本文研究了铁磁形状记忆合金复合材料在磁力驱动器中的应用。对复合板、螺旋弹簧的超弹性变形分析方法进行了探讨，并根据分析结果确定了复合材料的组成材料和优化形状。其次，进行了磁体-结构耦合分析，讨论了通过较小的磁力获得大变形的形状。1)为了分析形状记忆合金的实际超弹性现象，对形状记忆合金的热力学本构方程进行了修正。2)基于几何条件推导了螺旋弹簧的应变分布，阐明了大变形区螺旋弹簧几何形状的变化规律。提出了螺旋弹簧大变形区载荷-位移关系的分析方法。3)进行了磁结构耦合分析，研究了复合材料的最佳厚度比和长度比。结果表明，最佳厚度比为0.4，最佳长度比为0.6。4)开发了低热输入摩擦焊接法作为复合材料的制造方法，并研究了通过有限元分析从摩擦焊接条件预测摩擦焊接初始扭矩时间即摩擦焊接结束时间的方法。结果，根据摩擦焊接条件可以预测初始扭矩和初始扭矩时间。

In this study, it was examined to apply the ferromagnetic shape memory alloy composite to a magnetic drive actuator. The method of the superelastic deformation analysis of the composite plate, the coiled spring was examined, and decided the composed materials and the optimization shape from the obtained results. Next, the magneto-structural coupled analysis was carried out, and the shape to obtain large deformation by smaller magnetic force was discussed. Moreover, the friction welding was examined as a manufacturing method of the composite.The main results obtained are as follows.1) To analyze the actual superelastic phenomenon, the thermomechanical constitutive equation of the shape memory alloy was corrected. The optimization composite plate shape and the selection guide of both materials were proposed.2) The strain distribution in the coiled spring was derived based on a geometrical condition, and the change in the coiled spring geometry in the large deformation region was clarified. Then it proposed the analytical method of the load-displacement relation in the large deformation region of the coiled spring.3) The magneto-structural coupled analysis was carried out, and the optimum thickness ratio and the length ratio of the composite were investigated. As a result, it was found that the optimum thickness ratio is 0.4 and the optimum length ratio is 0.6. In addition, it become clear that one layer connected composite plate is more suitable than two layer composite plate as actuator.4) The low heat input friction welding method was developed as a manufacturing method of the composite, and the method of predicting the initial torque time that was the friction welding end time from the friction welding condition by the FEM analysis was examined. As a result, an initial torque and the initial torque time were predictable from the friction welding condition.