A magnetic shape memory foil actuator loaded by a spring

This paper presents experimental and simulation results on the performance of a novel linear actuator that uses the magnetic shape memory (MSM) effect in a Ni?Mn?Ga foil device loaded by a mechanical spring. The linear MSM actuator shows reversible actuation cycles with maximum magnetic field induced strain change of 5.6% for optimized spring constant and prestress. The experimental results are compared with simulations based on a thermodynamics-based Gibbs free energy model. The model has been implemented in a finite element program, which uses beam elements and an integral magnetic solver. The simulations qualitatively describe the observed tensile stress dependence of the magnetostrain of the MSM foil actuator. We demonstrate that the effects of material inhomogeneity need to be taken into account to further improve the agreement with the experiment.

[1]  L. Schultz,et al.  Magnetically induced reorientation of martensite variants in constrained epitaxial Ni–Mn–Ga films grown on MgO(001) , 2008 .

[2]  M. Kohl,et al.  Evolution of local strain bands of different orientation in single crystalline Ni-Mn-Ga foils under tension , 2013 .

[3]  B. Krevet,et al.  A novel foil actuator using the magnetic shape memory effect , 2011 .

[4]  S. Hannula,et al.  Magnetic shape memory effect in thin foils , 2008 .

[5]  L. Schultz,et al.  Large superplastic strain in non-modulated epitaxial Ni–Mn–Ga films , 2010 .

[6]  G. Jakob,et al.  Correlation of electronic structure and martensitic transition in epitaxialNi2MnGafilms , 2007 .

[7]  A. A. Likhachev,et al.  Giant magnetic-field-induced strain in NiMnGa seven-layered martensitic phase , 2002 .

[8]  B. Krevet,et al.  Recent Progress in FSMA Microactuator Developments , 2009 .

[9]  L. Schultz,et al.  A fabrication technology for epitaxial Ni-Mn-Ga microactuators , 2008 .

[10]  M. Kohl,et al.  Development of Single Crystalline Ni-Mn-Ga Foil Microactuators , 2013 .

[11]  L. Schultz,et al.  Comparing properties of substrate-constrained and freestanding epitaxial Ni–Mn–Ga films , 2010 .

[12]  Christoph Adelmann,et al.  Shape memory and ferromagnetic shape memory effects in single-crystal Ni2MnGa thin films , 2004 .

[13]  S. Seelecke,et al.  A rate-dependent three-dimensional free energy model for ferroelectric single crystals , 2007 .

[14]  Alexei Sozinov,et al.  Recent breakthrough development of the magnetic shape memory effect in Ni–Mn–Ga alloys , 2005 .

[15]  V. V. Kokorin,et al.  Large magnetic‐field‐induced strains in Ni2MnGa single crystals , 1996 .

[16]  FEM simulation of a NiMnGa film bridge actuator , 2010 .

[17]  V. Lindroos,et al.  Crystal structure of three Ni-Mn-Ga alloys in powder and bulk materials , 2003 .