Magneto-mechanical Coupling Model Research Articles

Enhanced Magnetic Soft Robotics: Integrating Fiber Optics and 3D Printing for Rapid Actuation and Precision Sensing.

Timely, accurate, and rapid grasping of dynamic change information in magnetic actuation soft robots is essential for advancing their evolution toward intelligent, integrated, and multifunctional systems. However, existing magnetic-actuation soft robots lack effective functions for integrating sensing and actuation. Herein, we demonstrate the integration of distributed fiber optics technology with advanced-programming 3D printing techniques. This integration provides our soft robots unique capabilities such as integrated sensing, precise shape reconstruction, controlled deformation, and sophisticated magnetic navigation. By utilizing an improved magneto-mechanical coupling model and an advanced inversion algorithm, we successfully achieved real-time reconstruction of complex structures, such as 'V', 'N', and 'M' shapes and gripper designs, with a notable response time of 34 ms. Additionally, our robots demonstrate proficiency in magnetic navigation and closed-loop deformation control, making them ideal for operation in confined or obscured environments. This work thus provides a transformative strategy to meet unmet demands in the rapidly growing field of soft robotics, especially in establishing the theoretical and technological foundation for constructing digitized robots.

Magneto-Mechanical Coupling Analysis of Automobile Brake by Wire System Based on Giant-Magnetostrictive Actuator

Addressing the drawbacks of traditional automotive braking systems, including long hydraulic lines, heavy weight, and slow response speed, a new type brake by wire system based on giant-magnetostrictive material is proposed, which consists of giant-magnetostrictive actuator module and mechanical drive module. In this paper, CATIA software is used to establish a three-dimensional model of the brake. In order to verify the reliability of the model, giant-magnetostrictive actuator is taken as the research object, and COMSOL software is used to simulate different working conditions of automobile braking. A Magneto-mechanical coupling model was established and Magneto-mechanical coupling analysis of the actuator was carried out. The simulation results show that the aluminum shell material is superior to the 45 steel shell material. The inductance direction of the actuator is approximately elliptical from top to bottom, with uniform distribution of magnetic flux density and stress. The output stress is 5e4N/m2, and the maximum elongation is 0.1071mm. Finally, the driving efficiency of GMA was verified on an optical isolation platform, and comparative experiments were conducted before and after optimization using instruments such as laser displacement samplers, Tesla meters, and force sensors. The experimental results indicate that by optimizing the housing material and structure of the actuator, the displacement increased from 0.05188mm to 0.1003mm, magnetic induction increased from 42.9mT to 79.9mT, resulting in an increase of 41.6% and 42.7% respectively, and the maximum output force was 4752.3N. It makes a certain contribution to the application of GMA to automotive braking field and further proves the effectiveness of GMA in the application of automobile brake by wire system.

Simulation and Experimental Verification of Magnetic Field Diffusion at the Launch Load during Electromagnetic Launch.

The unique magnetic field environment during electromagnetic launch imposes higher requirements on the design and protection of the internal electronic system within the launch load. This low-frequency, Tesla-level extreme magnetic field environment is fundamentally distinct from the Earth's geomagnetic field. The excessive change rate of magnetic flux can readily induce voltage within the circuit, thus disrupting the normal operation of intelligent microchips. Existing simulation methods primarily focus on the physical environments of rails and armatures, making it challenging to precisely compute the magnetic field environment at the load's location. In this paper, we propose a computational rail model based on the magneto-mechanical coupling model of a railgun. This model accounts for the dynamic current distribution during the launch process and simulates the magnetic flux density distribution at the load location. To validate the model's accuracy, three-axis magnetic sensors were placed in front of the armature, and the dynamic magnetic field distribution during the launch process was obtained using the projectile-borne-storage testing method. The results indicate that compared to the previous literature methods, the approach proposed in this paper achieves higher accuracy and is closer to experimental results, providing valuable support for the design and optimization of the launch load.

Modeling on magnetization behavior of ferromagnetic material during cyclic deformation

In this paper, a nonlinear magneto-mechanical coupling constitutive model is established to describe the magnetization behavior of ferromagnetic materials under cyclic elastoplastic deformation. The critical state is introduced into the hysteretic magneto-mechanical model. In the critical state, the magnetization rates of loading and unloading are different. A new nonlinear plastic effective magnetic field is proposed by considering the effect of pinning sites caused by cross slip dislocation to describe the magnetization behavior under asymmetric cyclic loading. The softening factor and activation condition of plastic modulus parameter are introduced based on the cyclic plastic constitutive model to describe the decrease of plastic modulus. A new magnetization model for ferromagnetic materials under cyclic plastic deformation is established by combining the magneto-mechanical coupling model with the cyclic plastic constitutive model. Compared with the experiments and existing models, it is shown that the proposed model can capture the deformation and magnetization behavior well under cyclic loading.

A transient magneto-mechanical numerical model of a tank based on improved jiles-atherton theory

Magnetic field generated by the ferromagnetic material of underwater detectors varies with seawater pressure, which may affect the accuracy of deep-sea resource exploration. The effect of stress on magnetization is cumulative. In order to accurately simulate the influence of deep-sea pressure on the magnetic field around underwater detectors, it is very important to develop a transient magneto-mechanical numerical model. In this paper, a transient magneto-mechanical coupling model of a tank was developed to obtain the magnetic signal deviation caused by the magneto-mechanical coupling effect. By improving the Jiles-Atherton theory for complex stress and calculating the variation in magnetic field with pressure, the hysteresis effect between magnetization and stress was verified. Under different background magnetic fields, the effect of stress on magnetic field was determined by calculating the magnetic field distribution under different pressures.

Prediction of fatigue damage in ribbed steel bars under cyclic loading with a magneto-mechanical coupling model

As a ferromagnetic material, the magnetization of ribbed steel bars will change with the development of fatigue damage under cyclic loading, which can be used to evaluate the fatigue damage state of steel bars. However, the quantitative relationship between fatigue damage and the variation in magnetization is still unclear, and the existing magneto-mechanical model cannot be applied to ribbed steel bars directly. To accurately predict the magnetization and the fatigue damage state during fatigue, it is also necessary to consider the influence of stress concentration caused by ribs on stress and fatigue life. This paper proposes a magneto-mechanical model suitable for ribbed steel bars, which use the Neuber law and Coffin-Manson relationship to determine the stress range and fatigue life under stress concentration. Additionally, the magnetic induction intensity of the HRB400 ribbed steel bar in the tensile fatigue test was measured to verify the proposed model, and the mechanism of the magnetization change trend during fatigue was analyzed in detail. Through the fatigue damage formula based on the magnetic indicator, the simulation and experimental comparison results show that the proposed model can effectively describe the fatigue damage state of ribbed steel bars in the fatigue.

Study for Influence of Harmonic Magnetic Fields on Vibration Properties of Core of Anode Saturable Reactor in HVDC Converter Valve System

The cores of anode saturated reactor (ASR) are the main vibration source of the HVDC converter valve system. The ASR is excited with an impulse voltage, which contains many harmonic components, and the magnetostriction of cores is usually the main reason of the ASR vibration. Therefore it is significant to study the influence of the harmonic on the vibration of core of ASR. In this paper, the magneto-mechanical coupling model is established based on the magnetostriction theory and the expression of vibration acceleration in the presence of third harmonic is derived. The vibration test platform is built to test the core's vibration acceleration. The magnetic and magnetostrictive properties of silicon steel sheet under different working conditions are measured. The three-dimensional simulation model of the core is established, and the vibration acceleration under different magnetic flux density is calculated. The comparison of the experiment and simulation results shows the rationality of the magneto-mechanical coupling model. The influence of third harmonic magnetic flux density on vibration is studied by changing the phase of the third harmonic magnetic flux density and the ratio of the third harmonic magnetic flux density to the fundamental magnetic flux density. Both the calculated and measured results show that the third harmonic magnetic flux density affects the vibration acceleration according to the double-frequency components of the third harmonic, as well the sum-frequency and difference-frequency components of the third harmonic and fundamental frequency.

Research on transient multi-field coupling model of GMM under variable pressure in embedded GMA

To improve the output performance of embedded giant magnetostrictive actuators (GMAs) for non-circular hole precision machining and to describe the transient nonlinear hysteresis behavior of giant magnetostrictive material (GMM), the magnetostrictive process of GMM is analyzed in detail in this paper. Based on the J–A model and the Gibbs free energy model, a transient multi-field coupling model of GMM is developed by considering the eddy current effect, compression stress variation, and ΔE effect. The simulation results show that the hysteresis loop area increases with increasing driving frequency. The strain of GMM increases first and then decreases with increasing preloading stress. If the stiffness of the deformable bar is too large, the stress of GMM will increase rapidly, thus hindering the elongation of GMM. The simulation process combines the magneto-mechanical coupling model and the dynamic model of embedded GMAs. The simulation results at different excitation frequencies are basically consistent with the experimental data, indicating that the proposed model can predict the output displacement well and provide a theoretical basis for the optimized design of magneto-mechanical coupling for high-performance embedded GMAs.

A nonlinear magneto-mechanical coupling model for magnetization and magnetostriction of ferromagnetic materials

A new magneto-mechanical coupling model was proposed for ferromagnetic materials under applied stress and in magnetic fields. The proposed model is based on the thermodynamic theory of ferromagnetic materials and Jiles–Atherton–Sablic (J–A–S) theory with respect to the effective magnetic field. Compared with the existing models for ferromagnetic materials, the prediction results of this model are more consistent with the existing experimental results, and the prediction accuracy has been significantly improved. This model can more accurately predict the nonlinear changes in the magnetization and magnetostriction under the applied stress and magnetic field. In addition, the effects of applied stress and magnetic field on magnetization and magnetostriction of ferromagnetic materials are analyzed on the basis of magnetic domain theory. In conclusion, the proposed model can fully describe the effect of applied stress on magnetization, magnetic permeability, and magnetostrictive strain, and the effects of applied stress and magnetic field on total magnetostrictive strain (i.e., the ΔE effect); furthermore, it sufficiently reflect the nonlinear coupling properties of the magnetic field, magnetization, and magnetostriction for ferromagnetic materials under applied stress and in magnetic fields.

Magneto-mechanical coupling model of ferromagnetic materials under fatigue loading and its application in metal magnetic memory method

Fatigue damage of materials is generally evaluated by the degree of degradation of mechanical properties under fatigue loading. Existing experiments show that fatigue damage of ferromagnetic materials can also be evaluated utilizing changes in magnetization, but the quantitative relationship between magnetization changes and fatigue damage is still unclear. In this paper, a nonlinear magneto-mechanical coupling constitutive relation for ferromagnetic materials under fatigue loading is established based on the local equilibrium state of magnetization and the stress-strain response relationship in classical fatigue theory. The magnetic induction intensity of the ferromagnetic materials predicted by the present model increases with the number of cyclic loadings, and then tends to stabilize and finally increase rapidly, which is consistent with the existing experimental results. The model can also predict the evolution of complex magneto-mechanical coupling behavior under different loading times. In addition, the relationship between the evolution of spontaneous magnetic field (SMF) and fatigue damage for ferromagnetic materials is discussed in details. These results are helpful to understand the magneto-mechanical coupling behavior of ferromagnetic materials during fatigue damage process and also have important significance for the fatigue damage monitoring in practical engineering.

Analytical methods for the radial electromagnetic vibration of stator in permanent magnet motors with an amorphous alloy core

The urgent demand for high efficiency of electrical machines leads to the preliminary application of amorphous alloy, however the accompanying vibration problem becomes more complex. The radial electromagnetic vibration of the amorphous stator core in a permanent magnet motor is analytically investigated in this paper. The magnetic field distribution approach considering the slotted effects and eccentricity is proposed and the air-gap magnetic flux density is validated by the finite element method. The magnetization and magnetostriction characteristics of the amorphous alloy are obtained. The dynamic models for the stator core including yoke sections and the tooth-yoke sections are respectively established. The Maxwell stress and magnetostriction stress are integrated in the magneto-mechanical coupling model. Dynamic responses in the stator core for different radii, position angles and times are analyzed. Vibrations of conventional core with silicon steel and amorphous core are compared. The spatial and temporal characteristics of the dynamic responses in the stator core are explored. The origins and corresponding weights in the electromagnetic vibration at different rotating speeds are revealed. Experiments of a modified permanent magnet motor equipped with the amorphous core are conducted. The theoretical results are validated well by experiments. Results demonstrate that the vibration level of the amorphous core is larger than the silicon steel core when other conditions are the same. Radial vibrations of the stator core are caused by the Maxwell stress, magnetostriction stress and their interaction effects. The weight of magnetostriction effects is improved with the increasing rotating speed. These findings provide an insight into the mechanism of electromagnetic vibration in amorphous stator core and can be helpful for the design of high-efficiency electrical machines.

Modeling and experiments on Galfenol energy harvester

Vibration energy harvesting can solve the energy supplying problem of systems like wireless sensors networks. The Galfenol cantilever beam energy harvester is suitable for this application. According to the electromechanical conversion principle, the constitutive relation of Galfenol is built. A magnetization model is also established, based on the hysteresis model of Galfenol. Combining the magneto-mechanical coupling model, the constitutive relation of Galfenol and the electromagnetic induction law, the mathematical model of Galfenol vibration energy harvester is established. A hyperbolic curve-shaped cantilever beam is designed and its performance is compared to three types of cantilever beams: rectangle, trapezoidal, and triangle. The stress distribution, modal analysis and frequency response of these four shapes of beams are compared. The hyperbolic beam is more suitable for low frequency vibration harvesting. The strain on the beams, output voltage and power output response to these energy harvesters, under different natural vibration frequencies, are determined by simulation. Finally, the simulation results are compared to experimental electric outputs of all four types of prototype beams. The comparative study showed consistency between the experimental and the simulation results, and also that the peak-to-peak induction voltage value of the hyperbolic beam is larger than other shapes of energy harvesters, whose average value is at 269.8 mV. The maximum power output of the hyperbolic beam is 403.8 μW when connected with a 50 Ω resistance.

Study on Internal Detection in Oil–Gas Pipelines Based on Complex Stress Magnetomechanical Modeling

The pipeline stress internal detection technology is an international frontier subject in the field of pipeline internal detection, in which the micromagnetic method has a great application potential. However, the pipeline micromagnetic stress internal detection technology lacks an effective theoretical model as a scientific guide due to the complex stress distribution inside the pipe wall during the operation of the pipeline. In this article, based on the complex stress magnetomechanical coupling model, we have studied the corresponding relationship between the stress and the micromagnetic signal and analyzed the influence of the external magnetic field on magnetomechanical relationship under the nonmagnetic saturation condition. And the correctness of the theoretical model is proved by systematic experimental research. The results indicate that the stress has a one-to-one linear relationship with the micromagnetic signal in the stress concentration region. The error rate between the theoretical calculation result of the uniaxial stress magnetomechanical coupling model and the experimental result is 89.4%, and the error rate between the theoretical calculation result of the complex stress magnetomechanical coupling model and the experimental result is 0.5%, which proves that the complex stress magnetomechanical coupling model established in this article is more suitable for the data analysis of the pipeline stress detection. Further, the force magnetic change rate and the micromagnetic signal in the stress concentration region increase with the increase of the external magnetic field intensity in the nonmagnetic saturation state.

Evaluation of Magnetic-Mechanical Coupling Behavior of Multiphase Magnetostrictive Materials

An online control by the magnetic method is considered as a nondestructive evaluation approach to detect the variation of the microstructure. The magnetic model used for each phase is based on a magneto-mechanical coupling model, which is characterized, on the one hand, by the influence of applied field on the magnetic susceptibility and magnetostriction; on the other hand, it is characterized by the effect of mechanical stress on magnetization of a material. In order to predict the macroscopic behavior correctly, this model takes not only account for the multiphased state of dual-phase steels for each phase separately but also for the heterogeneity of stress and magnetic field through a self-consistent localization-homogenization scheme. The proposed multiscale approach is based on the hypothesis of domain energy balance, including the localization step, the local constitutive law application, evaluation of the volumetric fraction of martensite, and the homogenization step. Results are discussed and compared with experimental data from the literature.

Design, fabrication and evaluation of metal-matrix lightweight magnetostrictive fiber composites

A class of lightweight FeCo/AlSi magnetostrictive composites was prepared in this study to explore the feasibility for 1-3 metal-matrix magnetostrictive materials for serving as sensors, actuators and energy harvesters. The FeCo fibers were inset into the AlSi metal liquid and then the composites were solidified at a protective atmosphere. The microstructural observations for these FeCo/AlSi composites illustrate the presence of the element diffusion and the disappearance of the cold-rolled preferred orientation. The refined microstructure was obtained during solidification and then further improved the magnetostrictive properties of the FeCo/AlSi composites. A zigzag interface with well transfer in stress and strain between the FeCo fiber and AlSi matrix existed through both physical and chemical bonding. There are two different experimental groups in this work. One group is aimed to evaluate the effect of the diameter of the FeCo/AlSi composite on the output voltage under compression. Another group with different numbers of the FeCo fibers is employed for analyzing the effect of the volume fraction of the FeCo fiber on the output performance. The results exhibit that a smaller diameter for the lightweight 1-3 FeCo/AlSi composite contributes to exciting a greater output voltage. Furthermore, the output voltage is proportional to the number of the FeCo fiber. An optimal resistive load of 500 Ω for this harvesting setup is obtained. Theoretical analysis through a magneto-mechanical coupling model for the FeCo/AlSi composites was conducted for accurately predicting the practical output performance.

Reactor vibration reduction based on giant magnetostrictive materials

The vibration of reactors not only produces noise pollution, but also affects the safe operation of reactors. Giant magnetostrictive materials can generate huge expansion and shrinkage deformation in a magnetic field. With the principle of mutual offset between the giant magnetostrictive force produced by the giant magnetostrictive material and the original vibration force of the reactor, the vibration of the reactor can be reduced. In this paper, magnetization and magnetostriction characteristics in silicon steel and the giant magnetostrictive material are measured, respectively. According to the presented magneto-mechanical coupling model including the electromagnetic force and the magnetostrictive force, reactor vibration is calculated. By comparing the vibration of the reactor with different inserted materials in the air gaps between the reactor cores, the vibration reduction effectiveness of the giant magnetostrictive material is validated.

Vibration Suppression Evaluation of Smart Journal Bearing Using Giant Magnetostrictive Actuators

A new kind of smart hydrodynamic journal bearings with giant magnetostrictive actuators (GMA) is introduced. The static and dynamic displacement outputs of the designed GMA are up to tens of microns, about the same order of magnitude as the conventional journal bearing clearance. Vibration suppression of the new smart journal bearing is theoretically evaluated using a simple Jeffcott rotor-bearing system. Kinematic equations are set up including the magneto-mechanical coupling model for GMA. The bearing oil film force under large vibration is calculated using a fast and efficient non-stationary oil film database technique. The unbalance vibration orbit of the rotor center is simulated. A simple synchronous proportional control method for GMA with different control phases and gains is investigated. The suppress effect of unbalance vibration and improvement of oil whip unstable speed is evaluated. The simulation proves that the new journal bearing has better stability, and that rotor vibration can be actively suppressed.

Contribution of Magnetostriction to Transformer Core Vibration under DC Bias

An important source of transformer core vibration is magnetostriction of the thin silicon-steel lamination. In the power grid, direct current (DC) may form by solar magnetic storms and DC transmission. Transformer core supersaturation and harmonic increase in current caused by DC bias will intensify magnetostriction and produce additional transformer core vibration. In order to obtain transformer core vibration under DC bias, the magnetization curve and magnetostriction characteristics of thin silicon-steel lamination are measured. Then, this paper establishes a numerical magneto-mechanical strong coupling model including magnetostrictive effect under DC bias for three-phase three-column dry transformers. On the basis of the proposed model, and the measured magnetic characteristics of the thin silicon-steel lamination, transformer core vibration under DC bias and no-load condition has been calculated. In order to verify the proposed model, transformer core vibration under DC bias and no-load condition is studied experimentally. Numerical calculation results together with experimental results confirm the validity of the proposed method.

Study of Giant Magnetostrictive Thin Films With Gas Sensitive Layer for Use as Gas Concentration Sensors

Giant magnetostrictive thin films of double layers with gas sensitive layers as the sensing element being used to develop a gas concentration sensor were proposed in this paper. The double layers giant magnetostrictive thin films with gas sensitive layer were prepared. A magneto-mechanical coupling model was developed based on the assumption that the magnetostriction effect is equivalent to the effect of a body force. These films were tested in a cantilever arrangement and end deflection was measured. The measurement showed that the experimental results were in good agreement with the calculation results, demonstrating that the coupling model developed was effective. Furthermore, the results indicated that the giant magnetostrictive thin films with gas sensitive layer were very useful for gas concentration sensors.

MODEL AND EXPERIMENTAL STUDY OF GIANT MAGNETOSTRICTIVE POWER GENERATION

A mathematical model of vibration power generation (VPG) with the giant magnetostrictive material (GMM) is proposed on the basis of the magneto-mechanical coupling model, Jiles-Atherton model and electromagnetic induction law. According to the model, the output voltage of a giant magnetostrictive power generator has been calculated under the condition of different vibration frequency, pre-stress and bias magnetic field. The calculating results show that the model can reveal the relationship between the input vibrating stress and output voltage. The experiment of a giant magnetostrictive power generator has been carried out, and the experimental results agree well with the calculating results.