A nonlinear magneto-elastoplastic coupling model based on Jiles-Atherton theory of ferromagnetic materials

2021 ◽  
Author(s):  
Hu Xiangyi ◽  
Bu Yang ◽  
Zhang Jianhua
Keyword(s):  
Magnetic Field ◽  
Elastoplastic Deformation ◽  
Coupling Effect ◽  
Order Term ◽  
Ferromagnetic Materials ◽  
Experimental Results ◽  
Prediction Ability ◽  
Mechanical Coupling ◽  
Proposed Model ◽  
Anhysteretic Magnetization

Abstract As seen in the Jiles-Atherton (J-A) model and its modified form, the linear relationship between the magnetization coefficient and the stress deviates significantly from the experimental results. It is required to introduce many parameters that are difficult to obtain or unknown to describe the effect of elastoplastic deformation on magnetization or hysteresis, such as shape coefficient, pinning coefficient, and molecular field coefficient. In this paper, a new nonlinear magneto-elastoplastic model for ferromagnetic materials is established based on the magneto-mechanical coupling effect, and both the sixth-order term of magnetization and the nonlinear equation of the magnetization coefficient are introduced into the magnetostriction equation. In the models established in this paper, the elastoplastic deformation equivalent magnetic field is introduced into the effective magnetic field, and the Frohlich-Kennelly equation is used to describe the anhysteretic magnetization. After comparing the prediction results of different models with the available experimental results, it is observed that the proposed model in this paper exhibits superior prediction ability for magnetostrictive strain, magnetization, and hysteresis phenomena under different stresses. This paper has also analyzed the mechanism of the effect of elasto-plastic loading and residual plastic deformation on the hysteresis in different models as well as the differences between them. The determination coefficient of the proposed model in this paper is closer to 1 that is better than the existing models, indicating that it has a better fitting effect and is of great significance to the development of quantitative nondestructive testing technology.

scholarly journals Thermal network model and experimental validation for a motorized spindle including thermal–mechanical coupling effect

2021 ◽  
Author(s):  
Changjiang Zhou ◽  
Zefeng Qu ◽  
Bo Hu ◽  
Shengbo Li
Keyword(s):  
Network Model ◽  
Temperature Rise ◽  
Thermal Deformation ◽  
Coupling Effect ◽  
Dynamic Performance ◽  
Experimental Results ◽  
Motorized Spindle ◽  
Mechanical Coupling ◽  
Thermal Network ◽  
Proposed Model

Abstract Thermal deformation caused by temperature rise have an influence on the dynamic performance of a motorized spindle. In turn, the change in the dynamic performance will affect the temperature rise and thermal deformation of the system. However, the latter was rarely focused on in the previous literature. Therefore, a thermal network model of motorized spindle is enhanced by considering the thermal–mechanical coupling effect. Then, an iterative method is presented to solve the coupled equations, and a temperature test rig of the motorized spindle is set up to verify the proposed model. The relative error between the predicted and experimental results at two test points decreases by 9.56% and 3.44% after considering the thermal–mechanical coupling effect. The comparison with the experimental results shows that the proposed model with thermal–mechanical coupling effect can obtain a more accurate temperature field than the previous model.

Development of Numerical Code for Coupling Dynamical Response of Typical Tokomak Structures Using Volumetric Finite Element

2013 ◽  
Author(s):  
Zhensheng Yuan ◽  
Weixin Li ◽  
Jingyi Xu ◽  
Wenjing Wu ◽  
Zhenmao Chen
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Coupling Effect ◽  
Time Integration ◽  
Numerical Code ◽  
Dynamical Response ◽  
Vacuum Vessel ◽  
Integration Algorithm ◽  
Simulation Accuracy ◽  
Mechanical Coupling

Aiming to simulate the dynamical response of a non-ferromagnetic conductive structure in a strong magnetic field, a code of finite element method (FEM) was developed based on the reduced vector potential (Ar) method and a step by step time integration algorithm. The electromagneto-mechanical coupling effect was taken into consideration by adding ν × B term in the eddy current governing equation to calculate the additional electric field induced by the movement of the structure. The hexahedral isoparametric element was adopted in this code in order to simplify the correspondence between the simulation of electromagnetic force and the dynamical response, which enables the application of the code developed by authors to more complicated structures. To verify the validity of the new numerical code, the benchmark problem (TEAM-16) as a simplified model of Tokamak vacuum vessel structure was simulated. By numerical results contrasted between the current code and the ANSYS software, the code was proved to be more effective than typical commercial codes for structural analysis of a magneto-mechanical coupling problem. The simulation results proved that the new code can improve simulation accuracy especially in case of a large external magnetic field. In addition, the magnetic damping effect was also discussed in the paper.

Connected-Tube MPP Model for Unsupervised 3D Fiber Detection

2020 ◽  
Vol 2020 (14) ◽  
pp. 305-1-305-6
Author(s):  
Tianyu Li ◽  
Camilo G. Aguilar ◽  
Ronald F. Agyei ◽  
Imad A. Hanhan ◽  
Michael D. Sangid ◽  
...  
Keyword(s):  
Composite Material ◽  
Point Process ◽  
Marked Point ◽  
Experimental Results ◽  
Marked Point Process ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Proposed Model ◽  
Cylinder Model ◽  
Reinforced Composite Material

In this paper, we extend our previous 2D connected-tube marked point process (MPP) model to a 3D connected-tube MPP model for fiber detection. In the 3D case, a tube is represented by a cylinder model with two spherical areas at its ends. The spherical area is used to define connection priors that encourage connection of tubes that belong to the same fiber. Since each long fiber can be fitted by a series of connected short tubes, the proposed model is capable of detecting curved long tubes. We present experimental results on fiber-reinforced composite material images to show the performance of our method.

scholarly journals Impedance Modeling and Stability Analysis of DFIG-Based Wind Energy Conversion System Considering Frequency Coupling

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3243
Author(s):  
Shaojian Song ◽  
Peichen Guan ◽  
Bin Liu ◽  
Yimin Lu ◽  
HuiHwang Goh
Keyword(s):  
Stability Analysis ◽  
Coupling Effect ◽  
Impedance Model ◽  
Wind Energy Conversion ◽  
Proposed Model ◽  
New Type ◽  
Impedance Modeling ◽  
Frequency Coupling ◽  
Bus Voltage ◽  
Voltage Dynamics

Impedance-based stability analysis is an effective method for addressing a new type of SSO accidents that have occurred in recent years, especially those caused by the control interaction between a DFIG and the power grid. However, the existing impedance modeling of DFIGs is mostly focused on a single converter, such as the GSC or RSC, and the influence between the RSC and GSC, as well as the frequency coupling effect inside the converter are usually overlooked, reducing the accuracy of DFIG stability analysis. Hence, the entire impedance is proposed in this paper for the DFIG-based WECS, taking coupling factors into account (e.g., DC bus voltage dynamics, asymmetric current regulation in the dq frame, and PLL). Numerical calculations and HIL simulations on RT-Lab were used to validate the proposed model. The results indicate that the entire impedance model with frequency coupling is more accurate, and it is capable of accurately predicting the system’s possible resonance points.

Design and Fabrication of a Magnetocaloric Microcooler

2005 ◽  
Author(s):  
Sangchae Kim ◽  
Bharath Bethala ◽  
Simone Ghirlanda ◽  
Senthil N. Sambandam ◽  
Shekhar Bhansali
Keyword(s):  
Magnetic Field ◽  
Ambient Temperature ◽  
Temperature Change ◽  
Entropy Change ◽  
Temperature Sensors ◽  
Experimental Results ◽  
Maximum Temperature ◽  
Alternative Technology ◽  
Temperature Conditions ◽  
Si Wafer

Magnetocaloric refrigeration is increasingly being explored as an alternative technology for cooling. This paper presents the design and fabrication of a micromachined magnetocaloric cooler. The cooler consists of fluidic microchannels (in a Si wafer), diffused temperature sensors, and a Gd5(Si2Ge2) magnetocaloric refrigeration element. A magnetic field of 1.5 T is applied using an electromagnet to change the entropy of the magnetocaloric element for different ambient temperature conditions ranging from 258 K to 280 K, and the results are discussed. The tests show a maximum temperature change of 7 K on the magnetocaloric element at 258 K. The experimental results co-relate well with the entropy change of the material.

Experimental Study of Magnetic Field Variation Induced in Ferromagnetic Materials

2013 ◽  
Vol 312 ◽  
pp. 402-405
Author(s):  
Yang Yong ◽  
Dong Sun ◽  
Jie Ji
Keyword(s):  
Magnetic Field ◽  
Plastic Region ◽  
Steel Specimen ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Magnetic Memory ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Metal Magnetic Memory ◽  
Stress Increase

The fatigue tests on 15CrMo steel specimen were carried out and the metal magnetic memory (MMM) signals were detected. The experiment shows that the magnetic signals of specimen contain the information of stress distribution in the material inside. Furthermore, the experimental results show that the magnetic signals increase initial while then decrease slightly with the stress increase from 0kN to 200kN. Though analysis the MMM signals induced by different tensile stress within the plastic region of the specimen, a simple model was derived. The experimental results are consistent with the calculated results based on the Jiles-Atherton model.

Analysis of the Electro-Mechanical Responses of the Piezoelectric Motor Based on Finite Element Method

2014 ◽  
Vol 697 ◽  
pp. 181-186
Author(s):  
Zi Lei Wang ◽  
Tian De Qiu
Keyword(s):  
Finite Element ◽  
Coupling Effect ◽  
Complex Stress ◽  
Piezoelectric Resonator ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Mechanical Responses ◽  
Stress Boundary Condition ◽  
Piezoelectric Field ◽  
Stress Boundary

The piezoelectric field and structure field of piezoelectric resonator of ultrasonic motor are intercoupling. It is difficult to obtain the solution under some circumstances because of the complex stress boundary condition and the influence of coupling effect. An electro-mechanical coupling finite-element dynamic equation is established on the basis of the Hamilton’s Principle about piezoceramic and elastomer. The equation is decoupled through the shock excitation of the piezoelectric resonator and the piezoelectricity element and material provided by finite-element analysis. As a result, an admittance curve as well as the distribution status of the nodal DOF is obtained, which provides an effective method to solve electro-mechanical coupling problems.

scholarly journals Evaluation of a highly refined prediction model in knowledge-based volumetric modulated arc therapy planning for cervical cancer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Mingli Wang ◽  
Huikuan Gu ◽  
Jiang Hu ◽  
Jian Liang ◽  
Sisi Xu ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Prediction Model ◽  
Volumetric Modulated Arc Therapy ◽  
Model Evolution ◽  
Prediction Ability ◽  
Knowledge Based ◽  
Proposed Model ◽  
Arc Therapy ◽  
Knowledge Based Planning

Abstract Background and purpose To explore whether a highly refined dose volume histograms (DVH) prediction model can improve the accuracy and reliability of knowledge-based volumetric modulated arc therapy (VMAT) planning for cervical cancer. Methods and materials The proposed model underwent repeated refining through progressive training until the training samples increased from initial 25 prior plans up to 100 cases. The estimated DVHs derived from the prediction models of different runs of training were compared in 35 new cervical cancer patients to analyze the effect of such an interactive plan and model evolution method. The reliability and efficiency of knowledge-based planning (KBP) using this highly refined model in improving the consistency and quality of the VMAT plans were also evaluated. Results The prediction ability was reinforced with the increased number of refinements in terms of normal tissue sparing. With enhanced prediction accuracy, more than 60% of automatic plan-6 (AP-6) plans (22/35) can be directly approved for clinical treatment without any manual revision. The plan quality scores for clinically approved plans (CPs) and manual plans (MPs) were on average 89.02 ± 4.83 and 86.48 ± 3.92 (p < 0.001). Knowledge-based planning significantly reduced the Dmean and V18 Gy for kidney (L/R), the Dmean, V30 Gy, and V40 Gy for bladder, rectum, and femoral head (L/R). Conclusion The proposed model evolution method provides a practical way for the KBP to enhance its prediction ability with minimal human intervene. This highly refined prediction model can better guide KBP in improving the consistency and quality of the VMAT plans.

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