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The axial force will be altered as a result of the overturning influence exerted by both horizontal and vertical seismic events, as well as the secondary effects induced by gravitational loads. The variation of the axial force will greatly affect the seismic performance of reinforced concrete (RC) columns, thus warranting close attention. This paper proposes a hysteresis model of RC columns considering the cumulative damage effect under the action of variable axial force. First, three groups of cyclic loading tests were performed across three distinct groups. Subsequently, numerical analysis models were constructed, employing fiber-based finite element methods. Furthermore, according to the test and finite element simulation results, the existing damage value was modified to describe the degradation of the stiffness and load-bearing capacity. Next, through a regression analysis, the skeleton curve was established. Finally, the hysteresis behavior under the influence of variable axial load was ascertained. The results, when compared with the experimental data, show that the proposed hysteresis model can accurately describe the seismic performance of RC columns under the influence of variable axial force. [ABSTRACT FROM AUTHOR]

To effectively respond to severe seismic events, accurate and efficient models for predicting structural performance are essential. In this study, a multi-task adaptive learning framework that integrates physical information from nonlinear hysteretic models into a Long Short-Term Memory (LSTM) network is proposed. This framework overcomes the shortcomings of purely data-driven approaches, which often overlook physical laws, by enhancing computational efficiency through the integration of gradient interactions, multi-task gradient loss factors, and dynamic balance weight strategies. Benchmark tests demonstrate that our method outperforms conventional physics-informed neural networks, achieving higher accuracy in earthquake response predictions. [ABSTRACT FROM AUTHOR]

As a high-temperature resistant damping material, reducing vibration by coating with M-shape metal rubber (MMR) in a pipeline system is a promising solution due to its energy dissipation induced by micro dry friction between metallic wires. The main challenge for dynamic calculation and performance evaluation of elastic-porous metal rubber (MR) is derived from the intricate spatial network structure. In this work, the dynamic properties including acceleration admittance and insertion loss of the MMR-coated pipeline system were conducted by numerical simulation and experimental analysis. The constitutive models used to characterize hysteresis phenomena, including Yeoh and Bergström–Boyce models, were identified with different density parameters and adopted for steady-state dynamic numerical analysis. The sine sweep frequency test was conducted to verify the accuracy of the developed numerical model. The results indicate that the maximum error of stress–strain curve between numerical prediction and experimental measurement is 10.7%. In the frequency range of 0–1 500Hz, the insertion loss of the MMR-coated pipeline system is positively correlated with the density of MMR, as opposed to the coating distance of pipeline clamps and the influence of excitation force is minimal. Furthermore, the error of dynamic response of the pipeline system in low frequency between the experiment and simulation is 4.7%, indicating that the accuracy of the hysteresis model in predicting the dynamic characteristic of MR materials is effective. [ABSTRACT FROM AUTHOR]

This paper develops a model for lithium-ion batteries under dynamic stress testing (DST) and federal urban driving schedule (FUDS) conditions that incorporates associated hysteresis characteristics of 18650-format lithium iron-phosphate batteries. Additionally, it introduces the adaptive sliding mode observer algorithm (ASMO) to achieve robust and swiftly accurate estimation of the state of charge (SOC) of lithium-iron-phosphate batteries during electric vehicle duty cycles. The established simplified hysteresis model in this paper significantly enhances the fitting accuracy during charging and discharging processes, compensating for voltage deviations induced by hysteresis characteristics. The SOC estimation, even in the face of model parameter changes under complex working conditions during electric vehicle duty cycles, maintains high robustness by capitalizing on the easy convergence and parameter insensitivity of ASMO. Lastly, experiments conducted under different temperatures and FUDS and DST conditions validate that the SOC estimation of lithium-iron-phosphate batteries, based on the adaptive sliding-mode observer and the simplified hysteresis model, exhibits enhanced robustness and faster convergence under complex working conditions and temperature variations during electric vehicle duty cycles. [ABSTRACT FROM AUTHOR]

The axial force will be altered as a result of the overturning influence exerted by both horizontal and vertical seismic events, as well as the secondary effects induced by gravitational loads. The variation of the axial force will greatly affect the seismic performance of reinforced concrete (RC) columns, thus warranting close attention. This paper proposes a hysteresis model of RC columns considering the cumulative damage effect under the action of variable axial force. First, three groups of cyclic loading tests were performed across three distinct groups. Subsequently, numerical analysis models were constructed, employing fiber-based finite element methods. Furthermore, according to the test and finite element simulation results, the existing damage value was modified to describe the degradation of the stiffness and load-bearing capacity. Next, through a regression analysis, the skeleton curve was established. Finally, the hysteresis behavior under the influence of variable axial load was ascertained. The results, when compared with the experimental data, show that the proposed hysteresis model can accurately describe the seismic performance of RC columns under the influence of variable axial force.

The concept of generalized plasticity theory provides an appealing approach to developing efficient finite element models that can improve computational performance and allow flexibility in customizing plastic response. In this work, we revisit its application in developing frame elements and reformulate a concentrated plasticity frame element to allow its axial force to interact with its end moments (N-M interaction). The proposed element formulation relies on the physical implication of axial plasticity and updates its definition accordingly. Inasmuch, a single axial plasticity history can participate in plasticity evolution and N-M interaction at both ends. The new formulation also redefines the hardening rules to recover desired hardening behavior, which is not available in the previous formulation. In terms of numerical performance, the new formulation removes the potential bifurcation issue when both ends experience identical pure axial plasticity history. The proposed frame element is a high-performing alternative to simulate zero-length plastic hinge frame members that are frequently used in simulations in seismic engineering. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries with silicon-graphite composite anodes feature an asymmetric and direction-dependent voltage hysteresis. Upon comparing established hysteresis models from literature, it was found that a separate modelling of charge and discharge direction is required for both the operator-based Preisach model and the differential equation-based one-state model, often referred to as Plett model. This paper presents the first bidirectional implementation of the one-state hysteresis model based on extensive measurements of first-order reversal branches of a Si/C NMC cell. The approach accounts for directionality but cannot deal with the complexity of the hysteresis traverses, so an extension of the Preisach model is discussed and found to be infeasible. This justifies the development of a novel hysteresis model, the trajectory correction hysteresis (TCH) model, that fulfils the identified requirements for bidirectionality, closed-loop property and direct data fit and can be generally applied to any cell chemistry. The TCH model considers the traverse starting point, which allows for the unambiguous definition of hysteresis states and enables the simulation of complex trajectories due to two correction mechanisms. The static and dynamic current profiles in complex hysteresis scenarios demonstrate superior performance with 4.5 mV mae compared to Preisach (19.6 mV mae) and Plett (11.7 mV mae) models.

Shape Memory Alloys (SMAs) are used to design actuators, which are one of the most fascinating applications of SMA. Usually, they are on-off actuators because, in the case of continuous actuators, the nonlinearity of their characteristics is the problem. The main problem, especially in control systems in these actuators, is a hysteretic loop. There are many models of hysteresis, but from a control theory point of view, they are not helpful. This study used an artificial neural network (ANN) to model the SMA actuator hysteresis. The ANN structure and training method are presented in the paper. Data were generated from the Preisach model for training. This approach allowed for quick and controllable data generation, making experiments thoroughly planned and repeatable. The advantage and disadvantage of this approach is the lack of disturbances. The paper’s main goal is to model an SMA actuator. Additionally, it explores whether and how an ANN can describe and model the hysteresis loop. A literature review shows that ANNs are used to model hysteresis, but to a limited extent; this means that the hysteresis loop was modelled with a hysteretic element.

This paper develops a model for lithium-ion batteries under dynamic stress testing (DST) and federal urban driving schedule (FUDS) conditions that incorporates associated hysteresis characteristics of 18650-format lithium iron-phosphate batteries. Additionally, it introduces the adaptive sliding mode observer algorithm (ASMO) to achieve robust and swiftly accurate estimation of the state of charge (SOC) of lithium-iron-phosphate batteries during electric vehicle duty cycles. The established simplified hysteresis model in this paper significantly enhances the fitting accuracy during charging and discharging processes, compensating for voltage deviations induced by hysteresis characteristics. The SOC estimation, even in the face of model parameter changes under complex working conditions during electric vehicle duty cycles, maintains high robustness by capitalizing on the easy convergence and parameter insensitivity of ASMO. Lastly, experiments conducted under different temperatures and FUDS and DST conditions validate that the SOC estimation of lithium-iron-phosphate batteries, based on the adaptive sliding-mode observer and the simplified hysteresis model, exhibits enhanced robustness and faster convergence under complex working conditions and temperature variations during electric vehicle duty cycles.

A hysteresis motor produces output torque through the hysteresis effect of magnetic materials. It has the advantages of a simple structure, high-speed operation, high temperature resistance, low noise and self-starting capability. It can be applied to some special occasions requiring high speed and high stationarity. However, its disadvantage is low torque density, low efficiency and low power factor. The permanent magnet hysteresis motor is a compromise of the characteristics of permanent magnet motor and hysteresis motor, and it can be self-starting in the case of having a torque density comparable to that of a permanent magnet motor. In addition, there are some new structures of hysteresis motors, which open up the direction for innovative applications. Due to the complexity of magnetic properties, the calculation methods and dynamic models of hysteresis motors and permanent magnet hysteresis motors are special and also depend on the research of hysteresis materials and hysteresis models. This paper starts from the principle and classification of the hysteresis motor, and different structures and the corresponding analysis methods are reviewed. The motors with new structures and new methods are emphasized, the innovation and contribution of existing research are summarized, and the development trend of hysteresis motors is described. [ABSTRACT FROM AUTHOR]

Giant magnetostrictive actuators (GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations, including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function (E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 µm and decreases the root-mean-square error in displacement to within 0.5 µm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data; it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining. HIGHLIGHTS: • Recent research progress of the Preisach model in the field of ultra-precision drives is reviewed. • The Preisach model is improved, and an improved hysteresis model for giant magnetostrictive materials is obtained. • The application of the improved model to magnetostrictive feedforward compensation is discussed. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to propose a practical approach for considering the soil – shallow foundation – superstructure interaction effect in nonlinear seismic analysis. Soil structure interaction is a complicated task dealing with various engineering problems. Taking into account the soil structure interaction extends beyond the numerical analysis, geotechnical investigation, or structural design fields. The artistry of considering the soil structure interaction effect lies in the balance between incorporating soil conditions and the superstructure into one collective model. Following this methodology alongside classical soil mechanics principles provides additional confidence to the structural engineering society in adopting a complete practical concept. The herein presented study introduces a fiber macroelement that represents the soil beneath shallow foundations. This allows for the direct utilization of the fiber macroelement in nonlinear pushover and dynamic analysis in commercial software, as well as its simple implementation in open software systems. The introduction of a procedure for forming the stiffness matrix of the element and a hysteresis soil model is also a key component. Special attention is devoted to obtaining the material backbone curve through experimental results and Eurocode 8’s procedures. Furthermore, this paper demonstrates the implementation of a macroelement for considering the soil-structure interaction effect in nonlinear seismic analysis within commercial software. The primary aim is to provide structural designers with a streamlined approach for incorporating soil conditions into superstructure analysis. Numerical analysis results from an example building with a reinforced concrete structure in commercial software highlight the significance of not underestimating soil conditions. This work emphasizes that relying solely on fixed models in everyday structural design could lead to dangerous and unexpected consequences.

Shape memory alloys (SMAs) are widely used in aerospace, automobile, and other fields because of their excellent properties, such as large driving force and large deformation. A training method with a bidirectional memory effect is proposed for SMA actuators. The trained SMA units can be heated and cooled to change their shape (shorten and extend). The trained SMA is used as an actuator to drive the deformation of a structure. Due to the obvious hysteresis characteristics of SMA, a temperature-displacement hysteresis model based on the Preisach model is proposed in order to reduce the influence of hysteresis in the process of structural deformation. The F function method (FFM) is used for Preisach numerical implementation, and a PID control method is used for the precise control of structural deformation. Compared with the PID control method without hysteresis model, this method is superior to the PID control method in response speed and control accuracy. The maximum relative error of three target points in the experiment is 5.45%, which is better than the PID control method without this model. The hysteresis model can be applied to the displacement control of a SMA-based actuator. [ABSTRACT FROM AUTHOR]

The fast tool servo (FTS) technology has unique advantages in the machining of complex surfaces such as special-shaped targets and free-form surfaces. In view of the shortcomings in the performance of the existing FTS device, this paper puts forward a novel FTS which uses two piezoelectric ceramics instead of flexure hinges to provide restoring force. Firstly, the feasibility of the double-drive principle is verified theoretically, and the corresponding mechanism is optimized accordingly. Then, the system control hysteresis model is established and identified, and the appropriate control strategy is designed. Finally, the performances of the proposed FTS device are tested, and a typical microstructure is machined based on the device and ultra-precision lathe. The results indicate that the proposed device effectively improves the performance of the FTS system, which is useful for the processing of microstructures and free-form surfaces. [ABSTRACT FROM AUTHOR]

Accurate modeling of the coupling between mechanical and magnetic behavior is a key challenge for designing many electromagnetic devices. The requirements for such modeling are notably the ability to consider multiaxial configurations, thermodynamic consistency to allow the calculation of losses, and the implementability into structural analysis tools. So far, the modeling approaches available in the literature do not usually combine these three features simultaneously. In this paper, for the first time, the influence of mechanical stress on the magnetic hysteretic behavior is modeled through the association of a reversible simplified multiscale approach and a macroscopic energy-based magnetic hysteresis model in a vector-play form. A phenomenological description of the dissipation parameters under mechanical stress is proposed. The non-monotonic effect of tensile stress on the magnetic permeability is modeled using a second-order development in the magneto-elastic energy. Material parameters for both reversible and irreversible behavior are identified from experimental characterization under mechanical stress performed on a DC04 electrical steel. The experimental tests include anhysteretic and hysteretic measurements. Modeling results of the anhysteretic magnetic permeability, the coercive field, and the remanent induction under several levels of peak magnetic field and uniaxial mechanical stress are satisfactorily compared with those obtained experimentally. The model is shown to reasonably predict the hysteresis losses under tensile and compressive stress, as well as the response of the material under a complex magnetic field waveform with harmonic content.

The main purpose of the present study is to compute the input energy spectra of selected farfault ground motions (GMs) for linear elastic systems, and inelastic systems having a constant ductility ratio. Elastic-perfectly plastic (EPP) and Modified Takeda hysteresis models have been adopted in nonlinear modeling of single-degree-of-freedom (SDOF) systems. Accelerograms of far-fault GMs have been compiled from the Pacific Earthquake Research Center (PEER) database. Linear and nonlinear time history analyses have been performed using the selected GMs records for SDOF systems having a damping ratio of 5%. Input energy spectral ordinates have been computed in terms of energy equivalent velocity. The results have shown that there is no significant difference be tween elastic and inelastic input energy spectral values at intermediate and long periods. However, for short period systems, input energy demand imposed on inelastic systems is generally greater than that of imposed on elastic systems. For short period systems, it can be inferred from the computations of the study that the input energy spectral values obtained using Modified Takeda hysteresis model are greater than those of other models that have been employed. However, input energy spectra for inelastic systems have no significant dependency on hysteresis models, especially for intermediate and long period systems. [ABSTRACT FROM AUTHOR]

A hysteresis motor produces output torque through the hysteresis effect of magnetic materials. It has the advantages of a simple structure, high-speed operation, high temperature resistance, low noise and self-starting capability. It can be applied to some special occasions requiring high speed and high stationarity. However, its disadvantage is low torque density, low efficiency and low power factor. The permanent magnet hysteresis motor is a compromise of the characteristics of permanent magnet motor and hysteresis motor, and it can be self-starting in the case of having a torque density comparable to that of a permanent magnet motor. In addition, there are some new structures of hysteresis motors, which open up the direction for innovative applications. Due to the complexity of magnetic properties, the calculation methods and dynamic models of hysteresis motors and permanent magnet hysteresis motors are special and also depend on the research of hysteresis materials and hysteresis models. This paper starts from the principle and classification of the hysteresis motor, and different structures and the corresponding analysis methods are reviewed. The motors with new structures and new methods are emphasized, the innovation and contribution of existing research are summarized, and the development trend of hysteresis motors is described.

The magnetization properties of low-coercive-force (LCF) permanent magnets (PMs), i.e., remanent flux density, coercivity, and hysteresis curve slopes, are closely related to the magnetization characteristics of variable flux memory machine (VFMM). Therefore, this article investigates the inherent relationship between the properties of LCF PMs and electromagnetic characteristics of VFMM using a combined solution integrated with magnetic equivalent circuit (MEC) and graphical methods. First, the hysteresis curve of the LCF PM is analytically modeled by a simplified piecewise linear hysteresis model to characterize the mathematical relationships among the key parameters of the hysteresis model. Then, a simplified MEC method is used to obtain the permeability curves of VFMM, thereby further determining the intrinsic relationship between the dimensional parameters of the LCF PM and the electromagnetic characteristics of VFMM. Afterward, the flux regulation characteristics and on-load magnetization state (MS) stabilization capability of VFMM are qualitatively analyzed using a newly developed coupled approach. Furthermore, the electromagnetic characteristics of three VFMMs equipped with different version LCF PM materials are comprehensively compared using the finite-element (FE) method. Finally, a VFMM prototype using the selected AlNiCo magnet is manufactured and tested to verify the correctness of the theoretical and FE analyses. [ABSTRACT FROM AUTHOR]

This paper conducted experimental and numerical studies on the hysteretic behavior of eccentric rectangular hollow section (RHS) beam-to-column joints under cyclic in-plane bending. The study began with the design of both stiffened and unstiffened joints, followed by hysteresis tests that revealed failure modes like web weld tearing and stiffener fracture. The seismic performance of the joints was evaluated using hysteresis curves, skeleton curves, ductility coefficients, strength degradation coefficients, and energy dissipation coefficients. Compared to unstiffened joints, the stiffened joints exhibited a 30 % increase in peak load and a 18 % improvement in maximum energy dissipation coefficient. Subsequently, finite element (FE) analysis was performed, and the influence of key parameters on the hysteretic behavior was studied using validated FE models. The results indicated that the hysteretic behavior was positively correlated with the flange width ratio of beam to column, the ratio of beam section height to column flange width, and the thickness ratio of beam to column, while it was negatively correlated with the width-to-thickness ratio of the column. Finally, a mathematical model for the hysteretic behavior of both stiffened and unstiffened joints was developed and validated through experimental and FE comparison, offering practical applicability in engineering design. • Hysteresis tests on stiffened and unstiffened eccentric RHS beam-to-column joints are conducted. • The seismic performance of eccentric RHS beam-to-column joints is evaluated using various indices. • The influence pattern of key parameters on the joints' hysteretic behavior is investigated. • The mathematical model for eccentric RHS beam-to-column joints is developed. [ABSTRACT FROM AUTHOR]

The hysteresis model of the friction pendulum bearing (FPB) is very important for predicting its seismic performance. The previous hysteresis model is based on the horizontal force balance theory and cannot analyze the moment required when the FPB rotates. Because of this, this paper proposes a hysteresis model of the FPB based on the moment balance theory, which can be used to analyze the rotation performance of the FPB. In this paper, formulas of the hysteresis model of the FPB based on the moment balance theory are derived firstly. And it is found that the hysteresis loops calculated based on the moment balance theory is very close to those obtained from experiments. Then two main assumptions of the hysteresis model of the FPB based on the moment balance theory: Small rotation assumption and Normal stress assumption are introduced, and the expression of the hysteresis model of the FPB based on the moment balance theory without using the two assumptions is given. Finally, errors caused by the assumptions are analyzed in detail and the applicability of the simplified formula is verified.

Infill walls are a primary source of structural loss under service level and design basis earthquakes, so developing high-performance infill wall is an effective strategy to reduce seismic loss. While several high-performance infill walls have been proposed, most studies only reveal the damage characteristics of infill walls at the component level. However, the interaction between infill walls and structures can alter the seismic response of structures and consequently affect the loss of infill walls under earthquakes. Therefore, it is necessary to investigate the seismic responses and loss of high-performance infill wall at the structural level. In this paper, the working mechanism and damage characteristics of the slotted infill wall (SIW) are firstly introduced and verified through cyclic loading test. Then, an in-plane hysteresis model of SIW is developed, and the calculation method of key parameters is proposed. Finally, a numerical analysis model of a 10-story frame with slotted infill wall (SIW-F) is developed to study the seismic response and seismic losses. The results indicate that SIW-F's displacement response is larger than that of the frame with ordinary infill wall (OIW-F) on most floors. However, the floor acceleration response is less. The seismic loss of SIW-F is less than that of OIW-F, particularly under design basis earthquakes. The repair cost ratio of infill wall decreases from 19% to 8%, the total repair cost of the SIW-F decreases by 41%, and the total repair time also reduces by 25%. • The working mechanism and damage characteristics of the SIW is Introduced and verified. • A general in-plane hysteresis model of SIW is proposed, and calculation methods of key parameters are suggested. • The seismic responses of 10-story frames with SIW and OIW are comparatively evaluated. • The seismic loss including repair cost and time of 10-story frames with SIW and OIW are discussed. [ABSTRACT FROM AUTHOR]

An innovative symmetrical hysteresis model for reinforced concrete (RC) rectangular hollow columns is presented. The Bouc–Wen–Baber–Noori (BWBN) model was selected to depict the inelastic restoring forces and was improved by introducing a coefficient to describe the relationship between stiffness degradation and peak displacement. Sensitivity analysis was conducted at the local and global levels to clarify the importance of each parameter in the improved BWBN model. As such, a hybrid intelligence algorithm named PSOGSA was employed to identify the parameters of the BWBN model utilizing quasi-static tests of 16 hollow columns. The empirical formulas were regressed to bridge the connection between the BWBN model and design parameters of hollow columns. The results showed that the hysteresis curves of the improved BWBN model calibrated by the PSOGSA agreed well with the measured loops. In addition, the accuracy of the empirical prediction method of hysteretic parameters was checked through comparison with other hollow members. The calibrated improved BWBN model produced more precise hysteretic responses for RC hollow columns, since the peak and residual performance levels were simultaneously considered. [ABSTRACT FROM AUTHOR]

Based on the Bouc-Wen model, a nonlinear hysteretic restoring force model is established with dynamic equations. The hardening and softening of the material after reaching the yield limit are described by the nonlinear restoring force-displacement hysteretic curve. The Gamultiobj algorithm and the group search optimization (GSO) algorithm are used to fit and identify the material softening and hardening hysteresis curves, respectively. The effectiveness of the optimization algorithm for identifying the parameters of the hysteretic model is verified, and the optimization effects of the two algorithms are compared. The results show that the Gamultiobj algorithm has better parameter identification ability and curve fitting ability for the hysteretic model. Then, the hysteresis curve describing the nonlinear characteristics of a clamp is obtained through the static stiffness experiment of the clamp. The experimental curve is fitted by the Gamultiobj algorithm. As a result, the nonlinear Bouc-Wen model parameters of the clamp are obtained, and the stiffness and damping of the clamp are recognized. The distribution statistics of the obtained parameters are performed, and it is found that each parameter satisfies a certain probability distribution, which indicates that the parameter identification result is reasonable.

Electromagnetic clutches are widely used devices in industrial applications when a torque must be transmitted between two components without mechanical contact avoiding friction and so reducing wear and maintenance time. Hysteresis clutches are a particular variant of electromagnetic couplers used when a constant torque from zero to the synchronous speed needs to be transmitted. This paper deals with the analysis, design and optimization of hysteresis clutches. After a brief introduction on the operating principle, a new method of analysis is then introduced. The latter allows a fast prediction of the performance of hysteresis couplers without sacrificing the accuracy of the performance evaluation even when adopting anisotropic magnetic materials. The introduced method, based on a static finite element simulation followed by a post-processing of the evaluated magnetic field, is then used within an automatic design procedure in order to identify the inevitable trade-offs encountered when optimizing the geometry of any hysteresis clutches with a given outer envelope. The obtained results are commented in-depth and allow to draw general design guidelines with special regards to the selection of the number of poles and the magnetic materials. The effect of the high level of anisotropy of the most common magnetic materials showing the highest energy density is carefully taken into account allowing to deduce the optimal preferred direction of magnetization.

Preisach density is drawing increasing attention for interpreting material properties for memory and storage electronics. Preisach density can be linked to the observed hysteresis loops via the Preisach model that is based on the superposition of relay operators. Reconstructing Preisach density from hysteresis is an ill-posed problem with nonunique solutions. To alleviate ambiguities, we address Preisach density reconstruction as a constrained subset selection task utilizing structured sparsity regularizations. We validate our approach under various simulation settings and apply it on experimental band-excitation piezoresponse spectroscopy (BEPS) datasets to gain insights in microstructure-dependent properties of the tip-surface contact.

Currently, lithium-ion batteries are mainly used as central power components in electric vehicles. Usually, accurate battery cell modeling and state of charge estimation are required in order to effectively use the lithium-ion batteries in electrified vehicles. For an elaborate battery cell modeling on a wide temperature range, we select a temperature-dependent battery cell modeling approach, which relies on one resistance plus second-order resistance-capacitance equivalent circuit model. In order to corporate some temperature effects into the modeling, we derive the sixth-order polynomial functions using the curve fitting algorithm. The functions contribute to the accurate battery cell modeling on the wide temperature range. For a practical usage of the functions in real-time embedded systems, we propose an offset-based lookup table technique. In addition, we propose a novel hysteresis voltage unit model for more accurate parameter estimation of hysteresis voltages. This also leads to more accurate battery cell modeling. Based on the battery cell modeling, we propose a temperature-dependent estimation method for state of charge. This approach exploits the extended Kalman filter, which is suitable for nonlinear characteristics such as the hysteresis effect. Experimental evaluation exhibits that the proposed estimation method outperforms the conventional approaches in the wide temperature range.

Shape memory alloys (SMAs) are widely used in aerospace, automobile, and other fields because of their excellent properties, such as large driving force and large deformation. A training method with a bidirectional memory effect is proposed for SMA actuators. The trained SMA units can be heated and cooled to change their shape (shorten and extend). The trained SMA is used as an actuator to drive the deformation of a structure. Due to the obvious hysteresis characteristics of SMA, a temperature-displacement hysteresis model based on the Preisach model is proposed in order to reduce the influence of hysteresis in the process of structural deformation. The F function method (FFM) is used for Preisach numerical implementation, and a PID control method is used for the precise control of structural deformation. Compared with the PID control method without hysteresis model, this method is superior to the PID control method in response speed and control accuracy. The maximum relative error of three target points in the experiment is 5.45%, which is better than the PID control method without this model. The hysteresis model can be applied to the displacement control of a SMA-based actuator.

The fast tool servo (FTS) technology has unique advantages in the machining of complex surfaces such as special-shaped targets and free-form surfaces. In view of the shortcomings in the performance of the existing FTS device, this paper puts forward a novel FTS which uses two piezoelectric ceramics instead of flexure hinges to provide restoring force. Firstly, the feasibility of the double-drive principle is verified theoretically, and the corresponding mechanism is optimized accordingly. Then, the system control hysteresis model is established and identified, and the appropriate control strategy is designed. Finally, the performances of the proposed FTS device are tested, and a typical microstructure is machined based on the device and ultra-precision lathe. The results indicate that the proposed device effectively improves the performance of the FTS system, which is useful for the processing of microstructures and free-form surfaces.

Shape Memory Alloys (SMAs) are used to design actuators, which are one of the most fascinating applications of SMA. Usually, they are on-off actuators because, in the case of continuous actuators, the nonlinearity of their characteristics is the problem. The main problem, especially in control systems in these actuators, is a hysteretic loop. There are many models of hysteresis, but from a control theory point of view, they are not helpful. This study used an artificial neural network (ANN) to model the SMA actuator hysteresis. The ANN structure and training method are presented in the paper. Data were generated from the Preisach model for training. This approach allowed for quick and controllable data generation, making experiments thoroughly planned and repeatable. The advantage and disadvantage of this approach is the lack of disturbances. The paper's main goal is to model an SMA actuator. Additionally, it explores whether and how an ANN can describe and model the hysteresis loop. A literature review shows that ANNs are used to model hysteresis, but to a limited extent; this means that the hysteresis loop was modelled with a hysteretic element., Competing Interests: The authors declare no conflict of interest.

The overall driving cycle efficiency of conventional permanent magnet synchronous machines (PMSMs) for electric vehicle tractions in a wide speed range is constrained due to the large field weakening current and high iron loss in high speed. The series hybrid permanent magnet variable flux machines (HPM-VFMs) which employ both low coercive force (LCF) magnets and high coercive force magnets are proposed to obtain high torque density and flexible air-gap flux density simultaneously. The key of HPM-VFMs design is the accuracy of hysteresis model of LCF magnets and operating principle analysis. This article contributes to clarify operating principle based on hysteresis model of AlNiCo magnets and propose a novel design consideration to reduce magnetizing and demagnetizing current. Based on the theoretical analysis, this article proposes a novel series HPM-VFM, in which the NdFeB and AlNiCo magnets are arranged separately. Furthermore, flux paths are designed to achieve appropriate interaction between two kinds of magnets. The proposed machine has features of wide magnetization state (MS) variation range, low magnetizing and demagnetizing current, and low risk of unintentional demagnetization. By manipulating the MS of the proposed machine, the losses of a wide speed range operation could be reduced. The comparison of efficiency maps and the worldwide-harmonized light vehicles test cycle driving cycle losses between the proposed machine and a conventional interior PMSM proves that the proposed machine achieves higher efficiency for electric vehicle. [ABSTRACT FROM AUTHOR]

This article introduces a thermally-compensated magnetic hysteresis model, capable of accurately determining core losses of ferrite materials while accounting for core temperature variations. The employed model is based on permeance-capacitance analogy and it captures the frequency-independent hysteresis effect with the help of the Preisach model. For validation purposes, a 100 kW, 10 kHz realized medium frequency transformer prototype is selected and modeled as a part of a full-bridge LLC resonant converter in a time-domain simulation environment. Conducted simulations show the ability of the thermally-compensated magnetic hysteresis model to impact the generated core losses for core temperatures of up to 120° C. Finally, a temperature-feedback loop within the transformer is successfully closed inside of a system-level simulation, allowing for a more precise determination of the core and winding steady-state temperatures. [ABSTRACT FROM AUTHOR]

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An innovative symmetrical hysteresis model for reinforced concrete (RC) rectangular hollow columns is presented. The Bouc–Wen–Baber–Noori (BWBN) model was selected to depict the inelastic restoring forces and was improved by introducing a coefficient to describe the relationship between stiffness degradation and peak displacement. Sensitivity analysis was conducted at the local and global levels to clarify the importance of each parameter in the improved BWBN model. As such, a hybrid intelligence algorithm named PSOGSA was employed to identify the parameters of the BWBN model utilizing quasi-static tests of 16 hollow columns. The empirical formulas were regressed to bridge the connection between the BWBN model and design parameters of hollow columns. The results showed that the hysteresis curves of the improved BWBN model calibrated by the PSOGSA agreed well with the measured loops. In addition, the accuracy of the empirical prediction method of hysteretic parameters was checked through comparison with other hollow members. The calibrated improved BWBN model produced more precise hysteretic responses for RC hollow columns, since the peak and residual performance levels were simultaneously considered.

In order to predict the performance of designed electric machines, and also based on which the high efficiency of the drive systems can be obtained, the accurate calculation of the iron loss is necessary. Taking modeling accuracy versus modeling complexity into account, this article proposes a general and accurate iron loss calculation method considering harmonics based on the loss surface (LS) hysteresis model and finite-element method (FEM). Compared with the previous triangular wave excitation, this article uses the data under sinusoidal wave excitation to establish the LS model, which is more convenient for engineering application. A specimen is tested for different flux densities with harmonics, the extensive results verify the modeling method. Due to a powerful hysteresis model, the iron loss calculation can be realized by the direct integration of hysteresis loops. A separated iron loss calculation package is developed, and it is combined with the commercial finite-element software to compute the iron loss distribution. The method that combines the LS model and FEM is proved feasible by comparing the calculated iron loss with the measured one for the Epstein frame. [ABSTRACT FROM AUTHOR]

Pneumatic artificial muscle (PAM) is attractive in rehabilitation and biomimetic robots due to its flexibility. However, there exists a strong hysteretic nonlinearity in PAMs and strong coupling between the output displacement and the output force. At present, most commonly used hysteresis models can be treated as two-dimensional models, which only consider the nonlinearity between the input and the output displacement of the PAM without considering the coupling of the output force. As a result, high-precision modeling and estimation of the PAM’s behavior is difficult, especially when the external load of the system varies significantly. In this paper, the influence of the output force on the displacement is experimentally investigated. A three-dimensional model based on the modified Prandtl–Ishlinskii (MPI) model and the Nonlinear AutoRegressive Moving Average with eXogenous inputs (NARMAX) model is proposed to describe the relationship and couplings among the input, the output displacement, and the output force of the PAM. Experiments are conducted to verify the modeling accuracy of the proposed model when the external load of the PAM varies across a wide range. The experimental results show that the proposed model captures well the hysteresis and couplings of the PAM and can precisely predict the PAM’s behavior.

Transformer topological duality‐based transient model (TDuM) has been widely used in the electromagnetic transient (EMT) simulation to consider the impact of core non‐linear features and windings arrangement on exciting current. In this study, the transformer TDuMs that specialized for geomagnetically induced current events studying were validated. After a summary of the transformer TDuMs' derivation and their parameters estimation methodologies, the numerical experiments were carried out to investigate the transformer TDuMs and their related key issues such as core's material types, loss factor of hysteresis model, linear leakage inductance, tank wall with EMT analysis software. The numerical results show a good agreement with the measured data in the field experiments with DC bias applied, which mean that using the transformer TDuM to calculate the exciting current under DC bias condition is feasible. Besides, some practical tips were proposed based on the parameters sensitivity analysis for estimating the transformer TDuMs' parameters to study the transformers' dynamics under DC bias condition. [ABSTRACT FROM AUTHOR]

Due to increasing complexity of power systems the task of ensuring adequate operation of relay protection becomes more urgent. Detailed mathematical models of relay protection together with modern power system simulators are proposed to be used as a solution of this problem. At the same time, the adequate simulation of instrumental transformers, in particular the magnetization process of the core, is very important because the waveform of signals controlled by relay protection largely determined by transducers' errors. The developed mathematical model of current transformer reproducing the magnetic hysteresis in accordance with the Preisach theory is presented in the paper. Unlike other similar models, the Preisach' particle distribution function in the developed model is based not on the reference typical magnetizing curves, but on the volt–ampere characteristic of current transformer. This approach is better applicable in practice, since typical magnetization curves are not always available and become less relevant during transformer operation. There are presented the results of impact assessment of different types and values of burden on current transformer operation and comparison of the implemented model with existing methods of magnetization and hysteresis modeling. The adequate behavior of the developed model has been confirmed by the research. [ABSTRACT FROM AUTHOR]

This article investigates the torque characteristics of a switched flux hybrid magnet memory machine (SF-HMMM) by employing a coupled solution combining a quasi-linear hysteresis model (QLHM) of low coercive force (LCF) magnet and frozen-permeability method (FPM). This provides an in-depth understanding of the torque production of SF-HMMM. The QLHM is utilized to characterize the repetitive remagnetizing/demagnetizing behaviors of LCF permanent magnets (PMs), while the FPM is employed to separate and quantify the torque contributions due to two sets of PMs and armature windings. The machine topology and analysis methodology are described, respectively. The torque segregation results accounting for magnetization state variation are analyzed by the proposed coupled solution. The influence of the LCF PM property on the torque segregation result is investigated to facilitate the establishment of general design guidelines. Finally, the prototype is tested to experimentally validate the theoretical analysis. [ABSTRACT FROM AUTHOR]

• Power transformers have a non-linear behavior due to the magnetic core saturation. • Saturation must considered because it affects their performance and efficiency. • This paper proposes a transformer model based on the inverse Jiles-Atherton theory. • Experimental results show that this model predicts core losses with accuracy. • The proposed model can be applied to many other magnetic devices. Power transformers are devices with non-linear behavior due to the saturation of the ferromagnetic core. When modelling such devices, the saturation effect must be taken into account because it greatly affects their performance and efficiency. In this paper, an electromagnetic model for power transformers is proposed and experimentally validated using an electrical T-model coupled with a reluctance network to model the magnetic part. The electrical circuit and the reluctance network are linked by two B–H approaches. The B–H relationships are modelled by the full hysteresis cycle based on the inverse Jiles-Atherton theory and by the initial magnetization curve. The results obtained with the inverse Jiles-Atherton theory model reproduce the magnetic core behavior with more accuracy than the one based on the initial magnetization curve, especially at low load conditions where saturation plays a more prominent role on the no-load current. The proposed model can be applied to other magnetic devices such as inductors for power electronic applications or electromechanical relays, among others. [ABSTRACT FROM AUTHOR]

• The effects of oil temperature on the hysteretic characteristics of the electro-hydraulic actuator are investigated experimentally. • A hysteresis model for electro-hydraulic actuator is established which can reflect the influence of oil temperature well. • A feedforward-feedback controller is designed to improve the pressure tracking error. • The performance of the proposed controller at different oil temperatures is verified experimentally. The hysteresis characteristics and oil temperatures of wet clutch electro-hydraulic actuators have a significant impact on clutch pressure tracking performance, thereby influencing the launch, shift, and mode transition performance of both fuel and hybrid electric vehicles. In this study, we introduce a novel compensator for wet clutch pressure hysteresis that effectively adapts to variations in oil temperature. Experimental investigations were conducted to examine the hysteresis characteristic of the electro-hydraulic actuator and its susceptibility to changes in oil temperature. Subsequently, a temperature-dependent modified generalized Prandtl–Ishlinskii (TDMGPI) hysteresis model that accounts for the influence of oil temperature was established. To mitigate the effects of oil temperature fluctuations on the controller, we developed a fuzzy proportional-integral-derivative (FPID) controller, which dynamically adjusts controller gain. Furthermore, a feedforward-feedback controller for clutch pressure was established, incorporating the inverse solution of the TDMGPI model as the feedforward component and the FPID controller as the feedback element. The experiments were conducted at various oil temperatures, revealing that the proposed controller significantly enhances response speed and pressure tracking accuracy, maintaining good control performance across the tested range of oil temperatures. [ABSTRACT FROM AUTHOR]

This paper presents the characterization and hysteresis modeling of magnetorheological (MR) damper with meandering type valve. The meandering type MR valve, which employs the combination of multiple annular and radial flow passages, has been introduced as the new type of high performance MR valve with higher achievable pressure drop and controllable performance range than similar counterparts in its class. Since the performance of a damper is highly determined by the valve performance, the utilization of the meandering type MR valve in an MR damper could potentially improve the damper performance. The damping force characterization of the MR damper is conducted by measuring the damping force as a response to the variety of harmonic excitations. The hysteresis behavior of the damper is identified by plotting the damping force relationship to the excitation displacement and velocity. For the hysteresis modeling purpose, some parts of the data are taken as the training data source for the optimization parameters in the neuro-fuzzy model. The performance of the trained neuro-fuzzy model is assessed by validating the model output with the remaining measurement data and benchmarking the results with the output of the parametric hysteresis model. The validation results show that the neuro-fuzzy model is demonstrating good agreement with the measurement results indicated by the average relative error of only around 7%. The model also shows robustness with no tendency of growing error when the input values are changed.

Featured Application: This study constructs and analyzes the constitutive model of the giant magnetostrictive material actuator, which provides a theoretical basis for the development of a new intelligent structure of giant magnetostrictive material. Giant magnetostrictive actuators (GMA) driven by giant magnetostrictive material (GMM) has some advantages such as a large strain, high precision, large driving force, fast response, high reliability, and so on, and it has become the research hotspot in the field of microdrives. Research shows there is a nonlinear, intrinsic relationship between the output signal and the input signal of giant magnetostrictive actuators because of the strong coupling characteristics between the machine, electromagnetic field, and heat. It is very complicated to construct its nonlinear eigenmodel, and it is the basis of the practical process of giant magnetostrictive material to construct its nonlinear eigenmodel. Aiming at the design of giant magnetostrictive actuators, the magnetization model based on a free-energy hysteresis model has been deeply researched, constructed, and put forward by Smith, which combines Helmholtz–Gibbs free energy and statistical distribution theory, to simulate the hysteresis model at medium or high driving strengths. Its main input and output parameters include magnetic field strength, magnetization, and mechanical strain. Then, numerical realization and verification of the magnetization model are done by the Gauss–Legendre integral discretization method. The results show that the magnetization model and its numerical method are correct, and the research results provide a theoretical basis for the engineering application of giant magnetostrictive material and optimized structure of giant magnetostrictive material actuators, which have an important practical application value. [ABSTRACT FROM AUTHOR]

Integrated battery charging (IBC)—multiplexing the motor windings as line inductors for charging electric vehicle battery packs—can improve the onboard charging capability without increasing the weight and cost. However, during the charging operation, currents flowing in the stator winding definitely generate a magnetic field, which may demagnetize the permanent magnets (PMs) in the PM traction motors. In this paper, the demagnetization effects of IBC current on magnets in interior PM machines are compressively investigated. In this paper, a recursive algorithm to update the PM magnetization states by using a parallelogram hysteresis model at different demagnetization levels is applied. The PM temperature is also considered for establishing this model. By coupling this algorithm to the finite element analysis, the demagnetization transit at different demagnetization levels can be assessed. By decomposing the flux density of each node within the magnets along its magnetization direction, irreversible demagnetization can be accurately evaluated. Impacts from both the pulsating and rotating demagnetization magnetic fields during the IBC operation are assessed and compared. [ABSTRACT FROM AUTHOR]

In this study, an experiment with four high-strength steel (HSS) end-plate connections was conducted. Compared with mild steel end-plate connections, the pinching effect of HSS end-plate connections is more obvious. Based on the comparison between the experiment results and the results of EC3 formulae, the requirement in EC3 could not be directly used in the design of the HSS end-plate connection. Given that the resistance and the prying forces of the idealized HSS T-stub are usually larger than that of mild steel T-stub, the effect of the bolt bending deformation and the beam flange rotation on the connection behavior of HSS end-plate connections could not be neglected. Hence, considering the aforementioned factors, the traditional multilinear model was modified in this study. Then, based on the modified multilinear model and the experiment result, a simplified hysteresis model was introduced to simulate the hysteresis properties of HSS end-plate connections. A validation was performed to prove that the modified multilinear model and the simplified hysteresis model can be used to predict the connection behavior of the HSS end-plate connection under cyclic loading. Furthermore, similar with the HSS T-stub, there are cracks in the heat-affected zone (HAZ) of the weld between the end plate and the beam. To investigate the damage accumulation and cracking problem of the HSS end-plate connection, a weighted value β determined by the experiment results and an ultimate plastic strain of HAZ were introduced in the damage cumulative model. • A cyclic experiment is conducted to investigate hysteresis properties of high-strength steel end-plate connections. • Moment-rotation curves and collapse behaviors of the HSS end-plate connection under cyclic loading are introduced. • Considering the bolt bending deformation and the beam flange rotation, a modified multilinear model is proposed. • A simplified hysteresis model is introduced to simulate the hysteresis properties of HSS end-plate connections. • A weighted value determined by experiment results is introduced in the damage cumulative model to study cracking problem. [ABSTRACT FROM AUTHOR]

In this paper, the influences of design parameters on the on-load demagnetization behavior of a switched flux hybrid magnet memory machine (SF-HMMM) are evaluated, which aims to provide a useful design guideline to avoid this performance degradation. The machine topology and on-load demagnetization phenomenon are described, respectively. Furthermore, some key design parameters are selected to optimize to elevate the operating point of the low coercive force (LCF) permanent magnets (PMs). Then, some geometric modifications are suggested to alleviate the on-load demagnetization effects. Finally, an SF-HMMM prototype is fabricated and tested to experimentally verify the finite-element analysis. [ABSTRACT FROM AUTHOR]

This paper presents an identification algorithm of the scalar Preisach model by using a set of symmetric minor hysteresis loops and suggests an improved vector Preisach model to describe the vector and anisotropic hysteresis behavior of a non-oriented (NO) electrical steel sheet (ESS) under rotating magnetic fields. Symmetric minor hysteresis loop is quite easy measured, so an identification algorithm based on symmetric minor hysteresis loop instead of first-order reverse curve is presented in this paper. The vector Preisach model employs a nonlinear coefficient, which is a function of magnitude and a direction of magnetic flux density, to describe the anisotropic property of the NO ESS and increases the numerical accuracy. The validity of the suggested vector Preisach model is investigated through comparisons with the experimental results under various magnetic field conditions. [ABSTRACT FROM AUTHOR]

One of the issues of an iron loss estimation is the modeling of an excess loss. This paper investigates the modeling method for the excess loss under dc-biased conditions. The proposed approach is based on the 1-D finite-element analysis for the silicon steel sheet in the thickness direction considering hysteretic property and skin effect. In addition, the magnetic flux density waveform is divided into the outline loop and minor loops and estimate the excess loss of each loop using the eddy current loss correction factor $\kappa $ taking account of dc-biased conditions. To demonstrate the effectiveness of the proposed method, we compare the estimated loss with measured one for the harmonic wave in single sheet tester. [ABSTRACT FROM AUTHOR]