Simple Hysteresis Model Research Articles

Improved simpler R/C hysteresis model considering biaxial interaction

From practical point of view, it is evident that the seismic wave acted on structures through two mutually orthogonal components which have significant combined effect on inelastic demands of the structure. Usually a smaller amount of ground motion generally applied in only one direction than the other and in most of the cases the studies considered only limited inelasticity. Therefore, further research is needed that considers ground motion in both horizontal directions with corresponding bi-directional intensities. Study shows, the combined effects cause significant amount of degradation of strength and stiffness which in turn cause early yielding of R/C(Reinforced Concrete) structural member. Conventional uni-axial model does not consider this type of bi-directional interaction. Some existing simpler bi-axial hysteresis model which can capture biaxial interaction shows satisfactory results, but still the deviation from experimental results are very prominent. On the other hand, some existing sophisticated bi-axial hysteresis model shows better accuracy in predicting response of R/C structural elements but these types of models require large number of calibrated test results which makes them case-specific. In this backdrop, by using principle of yield surface, this study aims to incorporate bi-directional interaction over a simpler hysteresis model which primarily able to capture uni-directional loading effects. Detailed computational scheme of the enhanced simpler uni-axial hysteresis model and extension of the model to capture bi-directional interaction with its performance in prediction of inelastic cyclic behaviour of R/C structural members are presented in this paper. From the performance point of view, it is clearly visible that the proposed simple bi-axial hysteresis model can predict experimental load–displacement curves of R/C structural members under bi-directional reversible loading with acceptable accuracy. The requirement of limited number of input parameters for the present proposed bi-axial hysteresis model make it more convenient to assess the progressive seismic damage under bi-directional ground motion.

A new hysteresis modeling and optimization for piezoelectric actuators based on asymmetric Prandtl-Ishlinskii model

Piezoelectric actuators are core components in micromanipulation systems in the field of biomedicine. The asymmetrical hysteresis of piezoelectric actuators greatly affects its performance, and the existing asymmetric hysteresis models are either inaccurate or complicated. In this paper, an accurate and simple asymmetric hysteresis model is proposed based on the Prandtl-Ishlinskii (PI) model. Firstly, the Play operator is modified to be asymmetric to enhance its flexibility, and the influence of parameters on the operator is analyzed. Secondly, the Asymmetric Prandtl-Ishlinskii (API) model is proposed based on the asymmetric Play operator and verified by experiment. Compared with several existing models, the API model can describe the asymmetric hysteresis in a more accurate and simple manner under the same conditions. Thirdly, the parameters of the API model are optimized. Compared with the unoptimized API model, the optimized one can reduce the number of parameters and maintain high accuracy. Furthermore, the influence of the order on accuracy is discussed, and a guidance for selection of the order is provided. Last but not least, the optimized API model is used to compensate for the hysteresis. The experimental results show that the compensator based on this model can effectively suppress the hysteresis of the piezoelectric actuator.

Transient and Harmonic Unipolar Hysteresis Model of Piezoelectric Actuators Using a System-Level Approach

Thanks to their integrability and good electromechanical conversion abilities, piezoelectric actuators are a good choice for many actuation applications. However, these elements feature a frequency-dependent hysteresis response that may yield complex control implementation. The purpose of this paper is to provide the extension of a simple hysteresis model based on a system-level approach linking the strain derivative to the driving voltage derivative and taking into account the dynamic behavior of the hysteretic response of the actuator. The proposed enhancement consists of transient and harmonic regimes, allowing to extend the quasi-static model to dynamic behavior with any frequency. In particular, initial strain shift arising from stabilization and accommodation effects as well as frequency-dependent hysteresis shape are considered. The inclusion of the system dynamics in the model is obtained thanks to fractional derivatives and associated fractional transfer functions, allowing the consideration of the full actuator history as well as a fine tuning of the system dynamics over a wide frequency band. Finally, a numerical example of linearized control through compensation loop is provided, demonstrating the interest in the proposed approach for providing a computationally-efficient, simple yet efficient way for finely predicting the actuator response and thus designing appropriate controllers.

Iron Loss Analysis of Permanent-Magnet Machines by Considering Hysteresis Loops Affected by Multi-Axial Stress

This article describes a method to calculate iron loss of permanent-magnet machines by considering the hysteresis loops affected by multi-axial stress. A simple hysteresis model is introduced and modified by reluctivity and hysteresis loss increase ratios, which can be determined by core material experiments under uniaxial stress. This model is coupled with time-stepping finite-element analysis. The validity of the proposed method is confirmed by the core material experiments under multi-axial stress and measured characteristics of permanent-magnet machines. It is clarified that the accuracy of the proposed method is acceptable.

Relationships between grain size in self-developed soft magnetic composites and the Grucad hysteresis model

Abstract Soft magnetic composites (SMCs) have been in the spotlight of magnetic community due to their unique properties which can easily be tailored up to a specific application. The present paper is focused on the possibility to develop SMC cores produced from iron powder mixed with suspense polyvinyl chloride. Important processing parameters like grain size are correlated with the parameters of a simple phenomenological hysteresis model developed by the Grucad research group.

Evaluation of three energy balance-based evaporation models for estimating monthly evaporation for five lakes using derived heat storage changes from a hysteresis model

The heat storage changes (Qt) can be a significant component of the energy balance in lakes, and it is important to account for Qt for reasonable estimation of evaporation at monthly and finer timescales if the energy balance-based evaporation models are used. However, Qt has been often neglected in many studies due to the lack of required water temperature data. A simple hysteresis model (Qt = a*Rn + b + c*dRn/dt) has been demonstrated to reasonably estimate Qt from the readily available net all wave radiation (Rn) and three locally calibrated coefficients (a–c) for lakes and reservoirs. As a follow-up study, we evaluated whether this hysteresis model could enable energy balance-based evaporation models to yield good evaporation estimates. The representative monthly evaporation data were compiled from published literature and used as ground-truth to evaluate three energy balance-based evaporation models for five lakes. The three models in different complexity are De Bruin-Keijman (DK), Penman, and a new model referred to as Duan-Bastiaanssen (DB). All three models require Qt as input. Each model was run in three scenarios differing in the input Qt (S1: measured Qt; S2: modelled Qt from the hysteresis model; S3: neglecting Qt) to evaluate the impact of Qt on the modelled evaporation. Evaluation showed that the modelled Qt agreed well with measured counterparts for all five lakes. It was confirmed that the hysteresis model with locally calibrated coefficients can predict Qt with good accuracy for the same lake. Using modelled Qt as inputs all three evaporation models yielded comparably good monthly evaporation to those using measured Qt as inputs and significantly better than those neglecting Qt for the five lakes. The DK model requiring minimum data generally performed the best, followed by the Penman and DB model. This study demonstrated that once three coefficients are locally calibrated using historical data the simple hysteresis model can offer reasonable Qt to force energy balance-based evaporation models to improve evaporation modelling at monthly timescales for conditions and long-term periods when measured Qt are not available. We call on scientific community to further test and refine the hysteresis model in more lakes in different geographic locations and environments.

Hysteresis Compensation of Piezoresistive Carbon Nanotube/Polydimethylsiloxane Composite-Based Force Sensors.

This paper provides a preliminary study on the hysteresis compensation of a piezoresistive silicon-based polymer composite, poly(dimethylsiloxane) dispersed with carbon nanotubes (CNTs), to demonstrate its feasibility as a conductive composite (i.e., a force-sensitive resistor) for force sensors. In this study, the potential use of the nanotube/polydimethylsiloxane (CNT/PDMS) as a force sensor is evaluated for the first time. The experimental results show that the electrical resistance of the CNT/PDMS composite changes in response to sinusoidal loading and static compressive load. The compensated output based on the Duhem hysteresis model shows a linear relationship. This simple hysteresis model can compensate for the nonlinear frequency-dependent hysteresis phenomenon when a dynamic sinusoidal force input is applied.

Hysteresis curves of a resistance spot welding transformer

PurposeThe aim of the paper is to provide a simple and reliable hysteresis model for prediction of magnetization curves of a resistance spot welding transformer (RSWT) core, operating in a wide range of flux densities and excitation frequencies.Design/methodology/approachThe hysteresis model considered in the paper is the T(x) description advanced by J. Takács. Three options to extend the model to the dynamic magnetization conditions are considered. The excitation conditions differ from those prescribed by international standards.FindingsThe quasi‐static Takács model combined with a fractional viscosity equation similar to that proposed by S.E. Zirka outperforms other considered options. The effect of eddy currents may be considered as a disturbance factor to the frequency‐independent quasi‐static hysteresis loop.Research limitations/implicationsThe combined approach yields in most cases a satisfactory agreement between theory and experiment. For highest frequency considered in the paper (1 kHz) excessive “heels” were observed in the modelled loops. This artifact may be reduced by the introduction of a more complicated relationship for the viscous term. Future work shall be devoted to this issue.Practical implicationsThe combined Takács‐Zirka model is a useful tool for prediction of magnetization curves of a RSWT core in a wide range of flux densities and excitation frequencies.Originality/valueThe usefulness of the Takács description has been verified in a practical application. The model is able to predict magnetization curves under non‐standard excitation conditions.

One Domain Wall Hysteresis Model for Spherical Grain

The high uniaxial magnetic anisotropy makes phases like Nd2Fe14B, Sm2Co17, SmCo5or BaFe12O19are very suitable as hard permanent magnetic materials. In the case of ferromagnetic materials, the global magnetostatic energy changes, according to the domain wall configuration. The simplest case to be studied is that of spherical grain with only one domain wall, in phases with uniaxial symmetry. The magnetostic energy in this system is calculated by means of Legendre polynomials. Studying the maximums and minimums of energy in this system, a simple hysteresis model can be developed. The model provides insight about the dependence of the coercive force on the grain size.

繰返し複合応力を受けるせん断降伏型鋼梁ウェブの履歴挙動に関する実験

The purpose of this study confirms that the hysteretic behavior of structural member subjected to multi-axial cyclic loads can be predicted based on the uni-axial stress hysteretic model. In addition, it is provided on how to evaluate the hysteretic behavior of short span beam subjected to combined bending and shear force. For this purpose, the shear yield type beams are carried out under the simultaneous shear and bending moment loading. The numerical analysis of steel structural member under multi-axial loads was carried out and the material properties were determined from the simple hysteresis model under uni-axial stress. Comparing between the numerical analysis and test showed that numerical analysis using hysteresis model under uni-axial stress was applicable to predict global and local hysteretic behavior on the steel member. On the basis of numerical analysis results, the damage correlation between member and material could be evaluated.

Modeling dynamic hysteresis for giant magnetostrictive actuator using hybrid genetic algorithm

This paper establishes a simple and novel dynamic hysteresis model for giant magnetostrictive actuator by considering the eddy current loss, anomalous loss and structural dynamic mechanical behavior of the actuator. To obtain parameters of the model, a hybrid genetic algorithm is proposed. Comparisons between the experimental and calculated results show the validity and practicability of the model

Analytical hysteresis model

A relatively simple analytical hysteresis model is constructed based on transformations of the anhysteretic or normal magnetization curve. Lag and branching are realized by variable function transformations governed by the position of the last turning point in the hysteresis space. The result is a model with local memory; however, it exhibits accommodation and non-congruent minor loops. The model parameters can be identified by mapping the reversal curves up to the second order. For soft magnetic materials analytical approximations of the required functions can be found.

Modeling saturated and unsaturated ferroelectric hysteresis loops: An analytical approach

In ferroelectric materials, hysteresis behavior is very difficult to model due to its nonlinear and history-dependent characteristics. Among approaches that are able to describe unsaturated loops, many of them are either very complicated (numerical procedures must be employed) or the resulting loops contain some undesirable or defective features. In this work, a simple hysteresis model based on a special construction of the Preisach function is proposed. Explicit expressions for the polarization-field (P-E) responses under increasing and decreasing applied fields have been derived. The saturated and unsaturated P-E loops can be conveniently calculated by piecing together such responses. The technique is widely applicable to the modeling of ferroelectric hysteresis behavior of ceramics and polymers. As examples we study the applied field dependence of dielectric permittivity of a ferroelectric film and the remanent polarization of ferroelectric composites after ac poling. We find that the model predictions agree well with the experimental results.

Modelling dynamic hysteresis loops and iron losses by the use of equivalent circuits

PurposeThe aim of the paper is the formulation of a simple hysteresis model entirely based on generally accepted concepts.Design/methodological/approachAccording to this, the modelling of loops has been achieved by the application of the Langevin‐Weiss law of magnetization to transformer equivalent circuits. The loops are generated by the change of the phase of current, introduced by the resistance modelling iron loss. Differential circuit equations have been solved with the help of standard Mathcad procedures.FindingsIn spite of the simplicity of such approach, the accuracy of hysteresis loops and iron loss approximations is better than in PSpice simulations and the model can be easily extended to dynamic loops.Research limitations/implicationsThe application of the model is limited to lower frequencies, where the rise of frequency leads to the widening of the loops without the radical change of their shapes.Practical implicationsPresented approach may be useful in simplified analysis of low frequency transformer circuits and in the primary explanation of hysteresis phenomena for teaching purposes.What is original/value of paperContrary to other models based on saturation curves, the dynamic hysteresis loops presented in this paper are obtained with the use of basic laws and concepts, without the introduction of any additional assumptions and the separate treatment of the lower and upper branches of the loops.

Correlations in a one-dimensional hysteresis model

We present exact results for the spin–spin correlations of a one-dimensional simple hysteresis model. The model properties are obtained from non-equilibrium states of an Ising lattice with random local fields. Long-range correlations 〈 σ 0 σ n 〉 are of the form | n|exp(− λ| n|) rather than exp(− λ| n|).

Heat Storage in Urban Areas: Local-Scale Observations and Evaluation of a Simple Model

The flux density of sensible heat to or from storage in the physical mass of the city is determined for seven cities (Chicago, Illinois; Los Angeles, California; Mexico City, Distrito Federal; Miami, Florida; Sacramento, California; Tucson, Arizona; and Vancouver, British Columbia) in North America across a 308 latitudinal range. These cities have a variety of synoptic-scale climates and surface cover and structural morphologies. In all cases the ‘‘measured’’ storage heat flux is determined as the energy balance residual from direct observations of net all-wave radiation, and sensible and latent heat fluxes conducted using the same radiometer and eddy correlation techniques. Databases describing the surface characteristics around each site are developed from analysis of aerial photography and field surveys. Results indicate that storage heat flux is a significant component of the surface energy balance at all sites and is greatest at downtown and light industrial sites. Hysteresis behavior, of varying degrees, is seen at all locations. A simple objective hysteresis model (OHM), which calculates storage heat flux as a function of net all-wave radiation and the surface properties of the site, is found to perform well in the mean for most cases, with the notable exception of Tucson; but considerable scatter is observed at some sites. Some of this is attributed to the moisture, wind, and synoptic controls at each of the sites, and to hour-to-hour variability in the convective fluxes that the OHM does not simulate. Averaging over 2 to 3 h may be a more appropriate way to use the model. Caution should be used when employing the OHM in windy environments.

Capability of convection–dispersion transport models to predict transient water and solute movement in undisturbed soil columns

The capability of the convection–dispersion model coupled with the Richards equation to predict transient transport of water and solutes in porous media is studied in a laboratory soil column. The solutes used are 3H 2O as a conservative tracer and 14C-labeled dibutylphthalate (DBP) as a sorbing solute. To account for multiple nonideal transport processes, a model was developed that may consider hysteresis of the water retention curve, sorption nonequilibrium (sorption kinetics and sorption hysteresis) and mobile and immobile water domains during solute transport. The model parameters were determined independently from the transient experiments, but on the same soil column to avoid uncertainty in transferring results from one sample to another. The hydraulic properties of the soil column were estimated by a multistep outflow experiment using inverse modeling. Transport parameters were estimated form breakthrough curves of 3H 2O measured under steady-state flow conditions. The sorption parameters of DBP were determined using batch techniques. Matrix potentials in the soil could not be predicted using a simple hysteresis model. Whereas the prediction of the tracer transport was satisfactory, it was not successful for DBP, inspite taking all nonequilibrium processes into account. DBP showed an early breakthrough and fluctuations in the outflow concentrations, which were induced by changes in the hydraulic boundary conditions. These fluctuations are caused by exchange processes during redistribution. The results suggest that models based on equilibrium assumptions may not always be suitable to predict the observed transport patterns. A calibration of the multinonequilibrium convective–dispersive model with the measured data, however, was possible.

Wetland evaporation and energy partitioning: Indiana Dunes National Lakeshore

For most wetlands precipitation and evapotranspiration are the major components of water gain and loss. However, studies of the hydrology of wetlands largely ignore evaporation, or calculate it by difference or some very simple measure. As part of an integrated study of the hydrology and ecology of wetlands in the Indiana Dunes National Lakeshore, evaporation was measured directly as its energy equivalent, the latent heat flux, using eddy correlation techniques for a 10 day period in June 1994. In addition, data were collected on the other surface energy balance fluxes (net all-wave radiation and sensible heat flux), and ancillary meteorological variables (wind speed and direction, temperature, pressure, relative humidity, solar radiation and water depth). Overall, latent heat flux dissipated 48% of the available radiant energy, storage heat flux 35%, and sensible heat flux 17%. A simple hysteresis model for the storage heat flux was developed which performed extremely well. Proximity to Lake Michigan resulted in evaporation rates close to the equilibrium rate (average Priestley-Taylor α = 1.035), which were affected strongly by net all-wave radiation. Three commonly used models of evaporation, Penman, Priestley-Taylor (α = 1.26) and equilibrium (α = 1.0) are evaluated. The relative success of the equilibrium model, with its limited data requirements, offers great potential for longer-term modeling of water and energy exchanges in this type of wetland environment.

Magnetization reversal in Ni 80Fe 20/Cu/Co spin-valves

Magnetization reversal mechanisms in exchange coupled Permalloy/copper/cobalt systems have been investigated by Kerr microscopy. In the ferromagnetically (F) coupled layers, a strong wall directional anisotropy and non-reversible wall displacements are observed. In the antiferromagnetic case (AF), experiments indicate that the magnetization reversal partly occurs through the nucleation and propagation of an antiphase boundary. Comparison with a simple hysteresis model provides an estimate of the coupling constant.

Five‐Spring Element for Biaxially Bent R/C Columns

The cyclic behavior of reinforced concrete columns subjected to biaxial bending was determined using a hysteretic element consisting of five axial springs. Four composite springs and one concrete spring are used. Their basic properties are controlled by the calculated balanced moment and axial force. A new simple hysteresis model was used for the composite springs and an existing model was used for the concrete spring. The five‐spring element (FSE) was evaluated based on its performance in simulating the response of several reinforced concrete test specimens. The element appeared to be successful in reproducing the response as long as the peak axial force did not exceed the balanced axial force. The FSE was also used to determine the response histories for several bridges. The results indicate that the response histories found based on FSE can be considerably different from those based on an elastoplastic yield surface model.