Abstract:In this paper, the stress-and magnetic field-induced variant reorientation in a magnetic shape memory alloy (MSMA) sample is simulated by using the finite element method. This model is set up based on a three-dimensional setting with the whole sample and the surrounding space taken into account. A typical loading pattern is proposed on the sample. The unknowns of the model governing system include the spatial displacement vector, the scalar magnetic potential and some internal variables related to the effectiv… Show more
“…Additionally, all three possible crystal orientations are taken into account instead of the two-dimensional simplification. [10] gives a more comprehensive overview of the different models available.…”
“…Additionally, all three possible crystal orientations are taken into account instead of the two-dimensional simplification. [10] gives a more comprehensive overview of the different models available.…”
“…The governing PDE system of the current model can be explicitly solved by using an iterative numerical algorithm [4]. To show the validity of the current model, we consider a MSMA sample with cuboid shape and subject to perpendicularly applied magnetic and mechanical loadings (cf.…”
Section: Example Of Numerical Simulationmentioning
In this work, a variational approach is proposed to study the magneto-mechanical response of a single-crystalline MSMA sample. By proposing a total energy functional for the whole magneto-mechanical system, the governing PDE system is derived by calculating the variations of the total energy functional with respect to the independent variables. An iterative numerical algorithm is proposed to solve the governing PDE system. As an example, a MSMA sample with cuboid shape and subject to perpendicularly applied magnetic and mechanical loadings is considered. It can be seen that the magnetomechanical response of this sample can be predicted at a quantitative level. The whole procedure of variant reorientation in the sample can also be simulated.
“…Phenomenological models have been developed to predict macroscopic behaviors of MSM alloys based on the idea of moving TBs as well as domain wall boundaries. In many cases that is done by introducing internal variables that describe alloy microstructures: the volume ratio of different variants, the volume ratio of the magnetic domains, and the orientations of the magnetization vectors [31], [32], [33], [34], [35], [36], [37]. Many of these models were successfully implemented using numerical finite element techniques [34], [37], [38], including non-conventional ones, such as the absolute nodal coordinate formulation [39].A development of the model to study the quasi-static movement of TBs based on internal variables was reported in [40], and recent work [41] presents a numerical algorithm for studying the dynamic magnetomechanical response of MSM alloys.…”
Smart structures based on the magnetic shape memory (MSM) effect feature giant magnetic field-induced strains and an ultra-fast response. MSM alloys could be used in a variety of applications such as digital hydraulics, microfluidic systems, soft robotics. However, practical implementation of the MSM effect is complicated by a lack of precise engineering simulation tools suitable for designing structures using the MSM alloys. Presented here is an approach to calculating the difference in free energy across twin boundaries, which is the driving force for structural transformations in MSM alloys. The approach, based on 3D finite element simulations, makes it possible to consider an entire specimen while accounting for complex inner and outer non-homogeneous magnetic fields. Based on the simulation results obtained, conclusions are offered regarding the effect of different modeling approaches and experimental setups on free energy differences across twin boundaries.
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