Magnetic hysteresis modeling via feed-forward neural networks

A general neural approach to magnetic hysteresis modeling is proposed. The general memory storage properties of systems with rate independent hysteresis are outlined. Thus, it is shown how it is possible to build a neural hysteresis model based on feed-forward neural networks (NN's) which fulfills these properties. The identification of the model consists in training the NN's by usual training algorithms such as backpropagation. Finally, the proposed neural model has been tested by comparing its predictions with experimental data     

Magnetic hysteresis properties of internally oxidised Ni-Si alloys

Results are presented of magnetic hysteresis measurement made on some internally oxidised Ni-Si alloys. The alloys investigated were originally of nominal composition 0.058, 0.48, 0.77 and 0.96 wt % Si in Ni. Hysteresis loops have been obtained for all the alloys in both unoxidised and several internally oxidised states using a standard technique. The effect of the internal oxide precipitation on the coercivity and remanence of the specimens is made clear by these measurements. The dependence of coercivity on precipitate morphology and alloy compositions is considered and results of the variation of coercivity with the temperature of measurement in the range 20 to 265° C are discussed.     

Magnetic hysteresis and dissipative losses in superconducting films

An analysis is made of the response of thin-film superconductors to an oscillating magnetic field. The field strengths for defreezing and expulsion of the flux are determined. A hysteresis curve is plotted for the sample over the entire oscillation cycle of the magnetic field. The dissipative loss power is determined as a function of the amplitude of the alternating field. Pis’ma Zh. Tekh. Fiz. 23, 27–33 (June 12, 1997)     

A mean field Stoner-Wohlfarth hysteresis model

A model of magnetic hysteresis is proposed. It is based on the Stoner-Wohlfarth coherent rotation model, but with a macroscopic mean field interaction (similar to Weiss's molecular field theory), added to represent interaction between domains. Rotation of domain magnetization vectors gives both reversible and irreversible changes in bulk magnetization. A qualitative correlation is obtained between hysteresis curves calculated using this theoretical model and experimentally measured hysteresis curves of a ferrite permanent magnet     

Combination hysteresis model for accommodation magnetization

We describe an accommodation hysteresis model based on a combination of history-dependent and history-independent models. The amount of accommodation is changed by varying the weights of the models employed in the resulting model. We illustrate the operation of the proposed model with accommodating cycles attached to the major loop. The model can be useful in further investigations of the accommodation phenomenon, as we show by using complex trajectories constructed by it. It can be incorporated in magnetodynamic calculations and circuit analysis.     

Energy-based hysteresis model for magnetostrictive transducers

This paper addresses the modeling of hysteresis in magnetostrictive transducers in the context of control applications that require an accurate characterization of the relation between input currents and strains output by the transducer. This relation typically exhibits significant nonlinearities and hysteresis because of inherent properties of magnetostrictive materials. The characterization considered here is based on the Jiles-Atherton mean field model for ferromagnetic hysteresis in combination with a quadratic moment rotation model for magnetostriction. As demonstrated by comparison with experimental data, the magnetization model very adequately quantifies both major and minor loops under various operating conditions. The combined model can then be used to accurately characterize output strains at moderate drive levels. The advantages of this model lie in the small number (six) of required parameters and its flexibility under a variety of operating conditions     

A new hysteresis model for steel members

Since it is not economical to design structures to respond to earthquake loads in their elastic range, dissipation of energy by post‐elastic deformation has been recommended. This requires an understanding of the hysteretic behaviour of structural members. A mathematical model is proposed for the hysteretic response of steel members. The model is based on a pre‐defined skeleton curve, and consists of a linear and a non‐linear region. The linear region is twice the elastic length on the skeleton curve, while the non‐linear region is formed by superimposing an elliptical dissipation function on the skeleton curve. The shape of the proposed dissipation function and the hysteretic loops are compared with experimental results. Good agreement has been noted. Furthermore, it is shown that stiffness degradation can be easily incorporated in the model. While the model can currently by used in the analysis of accumulated damages for steel structures, it has the potential to be extended to reinforced concrete structures, as well. Copyright © 1999 John Wiley & Sons, Ltd.     

Bouc-Wen迟滞模型的改进与音圈电机非光滑迟滞特性的描述

Bouc-Wen模型是基于非线性微分方程的一种迟滞模型,由于三角波等非光滑输入拐点处导数不存在,此模型无法适应此类非光滑输入信号.受信号预处理方法启发,基于不完全微分的柔化思想,对Bouc-Wen迟滞模型进行了改进,论述了其对音圈电机非光滑迟滞特性描述的合理性,给出了改进模型的离散形式.在三角波输入下,对原模型和改进模型传输特性进行了仿真比较.结果表明,改进Bouc-Wen模型克服了原模型不足,能有效描述迟滞特性,可实现性好,算法简洁,特别符合高速实时要求.     

A hysteresis model for an orthogonal thin-film magnetometer

The operation of a ferromagnetic thin-film magnetometer using the anisotropic magnetoresistance effect in a permalloy film is discussed. Measurements showed the presence of a hysteresis effect not predicted by available models. It is shown that the sensitivity of the magnetometer is predicted by applying F.S. Greene and R.B. Yarbrough's (1970) orthogonal susceptibility model, and that the hysteresis can be explained by assuming dispersion in the magnitude of anisotropy. The orthogonal susceptibility model must be evaluated numerically, accounting for a finite driving field. The effect of an inhomogeneous demagnetizing field in the film is discussed in relation to magnitude dispersion of the anisotropy     

A hysteresis model for a stacked-type piezoelectric actuator

The hysteresis nonlinearity in piezoelectric materials brings difficulties in controlling the systems. In order to mitigate the effect of hysteresis, such nonlinearity needs to be characterized and modeled under different load circumstances. For this purpose, the actuator is modeled in terms of a mass-spring-damper system utilizing the stop operator as one of the operators of the Prandtl-Ishlinskii (PI) model. Merging the structural model with the nonlinear hysteresis model, we observe that the results demonstrate better correspondence to the measured output compared to that of the classical PI model for a wide range of working conditions, i.e., different input frequency and amplitude.     

Numerical implementation of the radial vector hysteresis model

This paper discusses the numerical implementation of a new vector hysteresis model, the radial vector model, introduced as general hysteresis vector model for both isotropic and anisotropic magnetic materials. The present implementation is a 2-D one that uses ellipses as critical surfaces. The results computed by the model, applied to some basic vector hysteresis configurations, are in agreement with experimental behavior.     

Magnetic core model

The paper presents a nonlinear electric circuit to describe the behaviour of magnetic cores in low-frequency applications. A method of hysteresis modelling is proposed, which is able to reproduce minor loops and remanent flux. Classic eddy-current losses and anomalous losses are represented by a linear resistor and a non linear resistor, respectively. The obtained results are compared with those calculated by the models of Hodgdon and Preisach. Comparisons with experimental results are also accomplished. This model is useful for transformer transient phenomena studies, such as inrush currents and ferroresonance     

超磁致伸缩换能器磁滞模型研究

本文主要阐述了超磁滞伸缩换能器的自由能磁滞模型,着重分析了该自由能磁滞模型的特点,巧妙地提出了能高效地实现此自由能磁滞模型的数值实现方法,通过与已有文献的计算数据和实验数据对比表明本文所提出的数值实现方法在提高计算效率的同时保证了计算精度.     

计及动态负载的气动肌肉驱动器迟滞模型

气动人工肌肉是一种新型的柔顺性驱动器,但由于采用硅胶等非线性材料而存在明显的迟滞现象,并且其滞环参数随着负载的不同而变化。本文基于广义Prandtl-Ishlinskii迟滞模型,引入气动肌肉的负载参数,建立了计及动态负载的迟滞模型Load-dependent generalized Prandtl-Ishlinskii(LG PI)。在0～100 N的负载范围内进行实验,验证了该模型能较好地描述气动肌肉在动态负载作用下的不对称迟滞特性,其滞环回路位置误差最大不超过1 mm。将LGPI模型的逆作为PID控制的前馈环节,以控制气动肌肉驱动的机械单指灵巧手手指,在不同负载下进行角度跟踪实验。与无前馈的PID控制实验结果对比分析表明,增加基于LGPI模型的前馈环节能提高控制系统的响应速度和控制精度。     

A domain evolution model for hysteresis in piezoceramic materials

In this paper, we use a circular distribution to quantify certain domain properties and model the hysteresis behavior of piezoceramic materials. The model is constructed by bridging the characteristics of microscopic domain distribution into the macroscopic (or bulk) behavior. Contributions, other than those associated with the polarization of domains, to bulk quantities are also counted. A domain orientation distribution function is first selected and the corresponding distribution function parameters are chosen as the internal state variables. For the two-dimensional model, a von Mises-Fisher circular distribution is used. Instead of micromechanical analysis of domain motions that would involve large computation efforts, the delineation of domain evolution is simplified by considering the evolution of the domain orientation distribution, which is determined by the dynamic variations of the internal state variables. We also develop a procedure to identify the material constants introduced in the constitutive equations. The models are used to quantitatively characterize various hysteresis loops observed in piezoceramic materials.     

A vector model for magnetic hysteresis based on interacting dipoles

A model for magnetic hysteresis is described in which the applied field intensity is free to rotate as well as vary in magnitude. The model is an infinite lattice of ellipsoidal Stoner-Wolfarth particles withN^{3} = 8,27,64,125,216...independent and not necessarily identical particles per unit cell. Techniques for making this simple yet very general model computationally tractable are described. The model is intended primarily for studying the magnetic recording process in particulate storage media.     

Data based model free hysteresis identification for a nonlinear structure

In the last two decades, the damage detection for civil engineering structures has been widely treated as a modal analysis problem and most of the currently available vibration-based system identification approaches are based on modal parameters, namely the natural frequencies, mode shapes and damping ratios, and/or their derivations, which are suitable for linear systems. Nonlinearity is generic in engineering structures. For example, the initiation and development of cracks in civil engineering structures as typical structural damages are nonlinear process. One of the major challenges in damage detection, early warning and damage prognosis is to obtain reasonably accurate identification of nonlinear performance such as hysteresis which is the direct indicator of damage initiation and development under dynamic excitations. In this study, a general data-based identification approach for hysteretic performance in form of nonlinear restoring force using structural dynamic responses and complete and incomplete excitation measurement time series was proposed and validated with a 4-story frame structure equipped with smart devices of magneto-rheological (MR) damper to simulate nonlinear performance. Firstly, as an optimization method, the least-squares technique was employed to identify the system matrices of an equivalent linear system of the nonlinear structure model basing on the excitation force and the corresponding vibration measurements with impact test when complete and incomplete excitations; and secondly, the nonlinear restoring force of the structure was identified and compared with the test measurements finally. Results show that the proposed data-based approach is capable of identifying the nonlinear behavior of engineering structures and can be employed to evaluate the damage initiation and development of different structure under dynamic loads.     

A phenomenological model for healing and hysteresis in rubber-like materials

We propose a predictive model for the dissipative behaviour of rubber-like materials. In the spirit of De Tommasi et al. [D. De Tommasi, G. Puglisi, G. Saccomandi, A micromechanics based model for the Mullins effect, J. Rheol. 50 (2006) 495-512], we assume that at the scale of the polymeric network the material is constituted by a distribution of links with variable activation and fracture thresholds. By considering the recross-linking effect due to unloading we obtain a three-dimensional, non-linear damage model that describes the rate-independent hysteretic behaviour observed in rubber-like solids. The feasibility of the model in treating complex non-homogeneous deformation histories is shown through a numerical application.     

Identification method for a circuit model of scalar static hysteresis

We present a new identification procedure for a hysteresis model based on nonlinear circuit cells. The response of elementary cells is equal to a generalized play operator. The procedure identifies exactly the limit symmetric hysteresis loop and can minimize the reconstruction error on minor loops. We present test cases for three different soft magnetic materials with peculiar behavior and we discuss the results.