Ferromagnetic shape memory alloys (MSMA) exhibit magnetic field- and stress-induced twinning when processed into single crystals, but are brittle and difficult to shape. Embedding slender single crystalline MSMA elements into a polymer matrix can thus provide composites with adjustable magnetic strain actuation behavior. Ni-Mn-Ga single crystalline rods were characterized for their magneto-mechanical behavior and embedded in two different types of epoxy matrices with different volumetric fractions. The magnetic actuation of the composites was measured and shown to depend on the Ni-Mn-Ga volumetric fraction and the matrix stiffness. This behavior was well predicted by finite element simulations of the composite using a simple material model for the strain of the MSMA as a function of the magnetic field and applied stresses. Guidelines for composite behavior prediction could thus be proposed. (C) 2015 Elsevier Ltd. All rights reserved.
#1Susanne Glock(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 4
#2Edgars Spārniņš(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 1
Last. Véronique Michaud(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 49
view all 4 authors...
Single crystals of ferromagnetic Ni-Mn-Ga shape memory alloys show magnetic-field and stress induced twinning, leading to shape memory. Adaptive composites can thus be produced by embedding single crystalline particles or bamboo-structured Ni-Mn-Ga fibres into a polymer matrix. To guarantee a durable performance of these composites, adhesion between reinforcement phase and matrix should be quantified and optimised. The influence of annealing and surface treatment with an aminosilane of melt-spun...
#1Susanne Glock(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 4
#2X.X. Zhang(HIT: Harbin Institute of Technology)H-Index: 10
Last. Véronique Michaud(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 49
view all 5 authors...
Ni-Mn-Ga is a ferromagnetic shape memory alloy that exhibits large, magnetic-field- and stress-induced strains via energy dissipating twinning when processed into single crystals. Grain boundaries suppress twinning and render polycrystalline Ni-Mn-Ga brittle. Ni-Mn-Ga/polymer composites overcome the drawbacks of polycrystals and could thus provide a less expensive and easier to handle alternative to Ni-Mn-Ga single crystals for damping applications. Ni-Mn-Ga wires were produced by melt-spinning ...
#1Jiong Wang(FAU: University of Erlangen-Nuremberg)H-Index: 7
#2Paul Steinmann(FAU: University of Erlangen-Nuremberg)H-Index: 71
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 variable...
Abstract Magnetic shape memory (MSM) materials based on non-stoichiometric Ni–Mn–Ga (NMG) alloys have attracted extensive interest over the last decade because of their actuating, sensing, and damping properties. In addition to MSM phenomenon, NMG alloys have shown conventional shape memory effect, traditional and magnetic-field-assisted superelasticity, magnetocaloric, and special transport properties. The multifunctionality of MSM alloys may be utilized for actuators, sensors, dampers, and per...
Composite materials consisting of magnetic shape memory alloy particles and a polymer matrix combine the advantages of both material classes: the high achievable magnetic field induced strain (MFIS) of 6% of Ni-Mn-Ga with a ductile matrix. Engineering the particle-matrix interface as well as matching stiffness of polymer matrix is of importance for achieving high reversible MFIS to use this material as actuator or damper. We investigated those properties for Ni50.9Mn27.1Ga22.0 and Ni50.3Mn24.6Ga...
#1Javier LLorca(UPM: Technical University of Madrid)H-Index: 73
#2Carlos González(UPM: Technical University of Madrid)H-Index: 42
Last. Luis P. Canal(UPM: Technical University of Madrid)H-Index: 11
view all 10 authors...
A bottom-up, multiscale modeling approach is presented to carry out high-fidelity virtual mechanical tests of composite materials and structures. The strategy begins with the in situ measurement of the matrix and interface mechanical properties at the nanometer-micrometer range to build up a ladder of the numerical simulations, which take into account the relevant deformation and failure mechanisms at different length scales relevant to individual plies, laminates and components. The main featur...
This paper is concerned with the finite element analysis of boundary value problems involving nonlinear magnetic shape memory behavior, as might be encountered in experimental testing or engineering applications of magnetic shape memory alloys (MSMAs). These investigations mainly focus on two aspects: first, nonlinear magnetostatic analysis, in which the nonlinear magnetic properties of the MSMA are predicted by the phenomenological internal variable model previously developed by Kiefer and Lago...
#2Peter Müllner(BSU: Boise State University)H-Index: 31
The off-stoichiometric Ni2MnGa Heusler alloy is a magnetic shape-memory alloy capable of reversible magnetic-field-induced strains (MFIS). These are generated by twin boundaries moving under the influence of an internal stress produced by a magnetic field through the magnetocrystalline anisotropy. While MFIS are very large (up to 10%) for monocrystalline Ni-Mn-Ga, they are near zero (<0.01%) in fine-grained polycrystals due to incompatibilities during twinning of neighboring grains and the resul...
Polymer composites inserted with high volume fraction of NiMnGa powders were fabricated and their magnetic-field-induced strain (MFIS) was investigated. It is found that MFIS of NiMnGa/polymer composites increases with the increase of volume fraction of NiMnGa powders in composites. Large MFIS of 950 ppm has been obtained along the orientation magnetic field while only 220 ppm was on the perpendicular orientation magnetic field.
Abstract Shape-memory polymer (SMP) is one of the smart materials that exhibit a shape-memory effect when exposed to external stimuli such as electricity, heat, moisture, etc. Although SMP possesses several advantages, they still numerous limitations, which led to the introduction of SMP composites. Herein, the main focus is to provide a comprehensive overview on SMPs and their composites (SMPCs), including their pros and cons along with a descriptive detail of their potential applications in va...
Increasing the spatial localization of the material response is crucial to increase the behavioral complexity of shape-memory polymer (SMP) actuators, which is strongly dependent on the spatial distribution of networks in SMP. An interesting approach is proposed in this work. We used diol crosslinkers with different fatty chain lengths to construct networks in biomass-derived poly(L-malic acid) (PMA), and thus obtained SMPs with different network geometries. The crosslinking followed a two-step ...
#1Liu Zhengxian(HIT: Harbin Institute of Technology)H-Index: 2
#2Xin Lan(HIT: Harbin Institute of Technology)H-Index: 17
Last. Jinsong Leng(HIT: Harbin Institute of Technology)H-Index: 64
view all 7 authors...
Abstract Shape memory polymer composites (SMPCs) are gradually applied to deployable space structures due to their special shape memory effect and excellent mechanical properties. The design, material properties and performances of a smart hinge based on SMPC were investigated in this paper. The micro-buckling problem of the inner sheet of the hinge was solved by designing the bending path. The mechanical properties of materials with different fiber layers were characterized. The performance inv...
Last. Defeng Wu(YZU: Yangzhou University)H-Index: 19
view all 4 authors...
A biomass-derived and biocompatible poly(L-malic acid) (PMA) based material with shape memory effect (SME) was developed in this work. 1,8-octanediol was used as the cross-linker to construct cross...
Abstract Light-induced shape-memory polymer (LSMP) materials have advantages of remote control and precise stimulation under suitable photoactive factors. The excellent performance, stability, and low cost are significant for LSMP materials. Herein, a novel stable and cheap LSMP was prepared with polyurethane (PU) and copper sulfide nanoparticles (CuS NPs) supported on modified cellulose nanocrystals (MCNC) (CuS NPs@MCNC). For the photosensitivity, CuS NPs were formed and assembled on MCNC witho...
#1Debottam Goswami(IIT-KGP: Indian Institute of Technology Kharagpur)H-Index: 2
#2K.S. Anand(IIT-KGP: Indian Institute of Technology Kharagpur)H-Index: 2
Last. Jayanta Das(IIT-KGP: Indian Institute of Technology Kharagpur)H-Index: 52
view all 6 authors...
Abstract We report the synthesis and characterization of a multifunctional composite obtained by integrating micron-sized Ni52Mn26Ga22 Heusler alloy particles into a polysulfone matrix. The Heusler alloy powders were synthesized by the ball milling of as-spun Ni52Mn26Ga22 ribbons and subsequently incorporated into a polysulfone matrix using the solution casting process. The microstructural, magnetic and thermomechanical properties of the alloy-polymer composites were investigated. X-ray diffract...
Shape memory polymers (SMPs) represent an intelligent polymeric material which can fix deformed temporary shape and recover their permanent shapes upon an external stimulus such that temperature, light, electricity, water, pH, magnetism and specific ions. This property is called shape memory effect (SME). The SME has underpinned its usefulness of SMPs in delicate minimally invasive surgeries (MIS’s) such as vascular stents, clot removals etc. The invasive biodegradable SMP devices can avoid seco...
Last. Hideki Hosoda(TITech: Tokyo Institute of Technology)H-Index: 38
view all 3 authors...
Abstract The outstanding role of internal stress in the silicone matrix driving a magnetostrain reversal of embedded particles of the Ni–Mn-Ga ferromagnetic shape memory alloy after removal of magnetic field, has been disclosed by finite element (FE) simulations and validated by experiment. For simulations, the three case studies have been considered: an isolated particle, and the particles pairs aligned parallel or perpendicularly to the applied magnetic field. The isolated particle provided a ...
