GMF双层膜几何非线性变形模型及实验研究

超磁致伸缩薄膜(GMF)在磁致伸缩效应下的变形具有明显的几何非线性特征,应用几何线性理论描述GMF的应力应变及本构关系存在较大误差.结合几何非线性弹性理论,并将磁致伸缩效应等效为GMF上体积力作用下的变形效应,建立了GMF双层膜的几何非线性变形模型,推导出了GMF在磁场作用下的挠曲线方程.用泰勒级数法求得了挠曲线模型的数值解,采用悬臂梁式超磁致伸缩双层膜(TbDyFe-Polyimide(PI)-SmFe和TbDyFe-Cu-SmFe)对模型进行了实验验证,结果表明,所提出的几何非线性挠曲线模型与实验结果具有较好的一致性.

A geometrical nonlinear deformation model and its experimental study of bimorph giant magnetostrictive thin film

The geometrical nonlinearity of giant magnetostrictive thin films(GMF) is detected under the magnetostriction effect.Thus,it is inaccurate to employ the geometrical linear elastic theory to describe the strain,the stress and the constitutive law of GMF.So with combining the nonlinear elastic theory,a nonlinear deformation model of bimorph GMF is established,based on the assumption that the magnetostriction effect is equivalent to the effect of body force loaded on GMF.With the Taylor series method,the numerical solution is deduced.Thereafter,experiments on cantilever-bimorph TbDyFe-Polyimide(PI)-SmFe and TbDyFe-CuSmFe are conducted respectively,to verify the proposed model.Results indicate that the nonlinear flexure line model is in good conformity with the experimental data.