Hysteretic Phenomena Research Articles

On the entropy inequality and its exploitation in continuum physics

The paper deals with the statement and the application of the entropy principle, through the Clausius–Duhem inequality, in continuum physics. The conceptual role is taken from the Coleman–Noll paper of 1963 thus leading to the physical admissibility of constitutive equations. The statement is generalized by letting the rate of entropy production be a constitutive property per se. This generalization proves essential in connection with the modelling of hysteretic phenomena. As to the application, the view of the Coleman–Noll procedure is maintained but a representation formula is shown to generalize the consequences of the entropy principle; as an example the modelling of heat conduction is investigated. Furthermore, while applying the entropy principle to magnetic materials, it is shown an interesting connection between the balance of angular momentum and the thermodynamic restrictions. Also, the modelling through rate-type equations shows the need of Lagrangian fields to obey objectivity and that of the entropy production as a constitutive function to account for the difference between loading and unloading processes.

Transient flow analysis of pool-type reactor coolant pump under flow coast-down

When power is off, the flow rate of coolant in the RCP decreases rapidly and irregular phenomena appear. However, the inflow coolant tends to be uneven and unsteady due to the design of coolant pool. To simulate the actual situation of pool-type RCP under flow coast-down, Circulation-loop model and Open-border model were established. It provides two prediction methods of the power-off condition of pool-type RCP. The flow rate of Open-border model drops synchronously with rotation speed, and that of Circulation-loop model is dynamically fed back through calculation. Variation trends of external characteristics of the two models are similar. However, it is found that a large-scale and low-speed vortex appears at the horizontal suction part of the pool in Circulation-loop model, blocking the coolant transport channel. Thus, there is obvious fluctuation and hysteretic nature phenomenon in the decline of flow rate compared to the decline of rotation speed in Circulation-loop model.

On the inadequacy of rate-dependent models in simulating asymmetric rate-independent hysteretic phenomena

Aim of this paper is to establish the limits of the common approach according to which, in oscillating systems, dissipative phenomena, often having an asymmetric rate-independent nature, are simulated by means of equivalent rate-dependent models relating forces and velocities. To this end we compare the time evolution of the generalized work and energy components of a Single Degree of Freedom (SDoF) hysteretic mechanical system including both conservative and non-conservative forces; in addition the generalized work of the non-conservative forces is related to the generalized internal energy of the system. To achieve such a result, we provide (closed-form) expression(s) to compute the path-dependent work performed by generalized rate-dependent (rate-independent) hysteretic forces, simulated by using the Seleemah and Constantinou (Asymmetric Bilinear) model. For the latter, we also provide a closed-form expression for the variation in internal energy associated with the generalized rate-independent work when a complete cycle of generalized displacement is applied. Such results are exploited to describe the behavior of symmetric, and asymmetric rate-independent hysteretic systems under loads of arbitrary nature, e.g., free vibration, harmonic load, and random load. Finally, the inadequacy of rate-dependent models in simulating asymmetric rate-independent hysteretic behaviors is assessed by showing that calibrating the former model according to the methodology usually suggested in the literature yields inaccurate results in terms of displacement and dissipated energy of the system.

Diverse seasonal hysteresis of surface urban heat islands across Chinese cities: Patterns and drivers

Understanding the seasonality of, and contributors to, surface urban heat island (SUHI) will pave the way for developing more generalized urban cooling strategies. The direction and shape of SUHI seasonal hysteresis have been thought to be background climate dependent. However, there remains a relative paucity of knowledge about the patterns and driving mechanisms of such hysteretic phenomena across diverse climates. Here we show that the seasonal hysteretic cycles of SUHI in the daytime and nighttime across Chinese cities between 2003 and 2020 can be identified as eight and six primary patterns, characterized by diverse and complex behaviors including clockwise, anti-clockwise, twisted, concave, and convex directions/loops. The urban-rural differences in evapotranspiration (ΔET) and surface albedo (ΔABD) have been recognized as the primary contributors to SUHI in the daytime and nighttime and their seasonal hysteresis, respectively, as measured by structural equation modeling (SEM) and time lead/lag analysis. These biophysical mechanisms for diverse seasonal hysteretic cycles of SUHI in China re-emphasized climate context dependencies in SUHI terms. Furthermore, the observed divergence of SUHI hysteresis typologies within similar background climates highlighted the additional drivers of complex urban systems because SUHI is a combined result of rural background and urban characteristics. We conclude that the cost-effective UHI mitigation strategies creating synergies or avoiding trade-offs among seasons should be climate context-specific and tailored to local urbanicity.

Techniques for the Thermodynamic Consistency of Constitutive Equations

The paper investigates the techniques associated with the exploitation of the second law of thermodynamics as a restriction on the physically admissible processes. Though the exploitation consists of the use of the arbitrariness occurring in the Clausius–Duhem inequality, the approach emphasizes two uncommon features within the thermodynamic analysis: the representation formula, of vectors and tensors, and the entropy production. The representation is shown to be fruitful whenever more terms of the Clausius–Duhem inequality are not independent. Among the examples developed to show this feature, the paper yields the constitutive equation for hypo-elastic solids and for Maxwell–Cattaneo-like equations of heat conduction. The entropy production is assumed to be given by a constitutive function per se and not merely the expression inherited by the other constitutive functions. This feature results in more general expressions of the representation formulae and is crucial for the compact description of hysteretic phenomena.

Numerical Modeling of Static Hysteresis Phenomena Using a Vector Extension of the Loss Surface Model

This paper proposes a vector extension of the Loss Surface model for numerically modelling hysteretic phenomena in electromagnetic device simulations with isotropic ferromagnetic materials. The vectorization strategy is based on Mayergoyz’s approach. The developed model has been implemented in the 2D finite element code. To handle the non linear problem solved with the Newton-Raphson algorithm, a suitable method is proposed for the approximation of the reluctivity tensor. Several test cases from TEAM problem 32 were investigated for validation. The results are in good agreement with measurements combining accuracy and short computation times.

Ferroelectric Polarization in an h-BN-Encapsulated 30°-Twisted Bilayer–Graphene Heterostructure

Recently, the emergent two-dimensional (2D) ferroelectric materials have provided new possibilities for the miniaturization of ferroelectric systems and the integration of novel 2D nano-electronic devices. In addition to the intrinsic ferroelectrics exfoliated from bulk, 2D heterostructures hybridized from electrically non-polarized van der Waals (vdW) materials have also been proven to be a promising platform for the construction of ferroelectricity. Here, we report 30° twisted bilayer–graphene (TBLG) incommensurate moiré superlattice encapsulated by hexagonal boron nitride (h-BN), in which robust hysteretic resistance was detected at the top interface between h-BN and the TBLG from room temperature down to 40 mK. The hysteretic phenomenon can be understood by the extra carrier induced by the interfacial 2D ferroelectric polarization, which is estimated to be around 0.7 pC/m. Our work of interfacial ferroelectric heterostructure achieved by a TBLG/h-BN hybrid system expands the 2D ferroelectric families and opens more possibilities for future coupling the ferroelectricity with rich electronic and optical properties in vdW twistronic devices.

A survey of Bouc-Wen hysteretic models applied to piezo-actuated mechanical systems: Modeling, identification, and control

Hysteretic nonlinearity behavior ubiquitously occurs in mechanical systems, particularly in high-precision instruments, which severely degrades system output performance. Consequently, it is unavoidable to establish an accurate hysteretic model to describe the hysteretic characteristic of various mechanical systems and to compensate for the system error caused by hysteresis. The piezo-actuated mechanism is one of the most frequent mechanical systems that occurs hysteretic phenomenon, explained in detail in this survey. Bouc-Wen (BW) model has been popularly applied in modeling hysteretic attributes due to the outstanding advantage of simple structure and identification process. This paper presents the latest BW model applications and investigates different BW models, identification methods, and control strategies in light of various application demands based on the BW model systematically. In addition, this survey is meaningful in choosing an appropriate modeling approach and control means for system design according to the distinct requirements, and in providing future research direction.

Deep learning-based wave digital modeling of rate-dependent hysteretic nonlinearities for virtual analog applications

Electromagnetic components greatly contribute to the peculiar timbre of analog audio gear. Indeed, distortion effects due to the nonlinear behavior of magnetic materials are known to play an important role in enriching the harmonic content of an audio signal. However, despite the abundant research that has been devoted to the characterization of nonlinearities in the context of virtual analog modeling over the years, the discrete-time simulation of circuits exhibiting rate-dependent hysteretic phenomena remains an open challenge. In this article, we present a novel data-driven approach for the wave digital modeling of rate-dependent hysteresis using recurrent neural networks (RNNs). Thanks to the modularity of wave digital filters, we are able to locally characterize the wave scattering relations of a hysteretic reluctance by encapsulating an RNN-based model into a single one-port wave digital block. Hence, we successfully apply the proposed methodology to the emulation of the output stage of a vacuum-tube guitar amplifier featuring a nonlinear transformer.

Preisach Mathematical Model of Hysteresis

Hysteretic nonlinear phenomena occur in many physical processes: ferromagnetism, adsorption, cyclic plasticity in mechanics, phase transformations, economics, etc. It is characterized by the fact that the same instantaneous values of input can give different outputs depending on the history of the input applied. It means that the relationship is not only nonlinear but also multivalued making it very difficult to model and control. In this paper, accent was given to the application to mechanics i.e. to cyclic plasticity of trusses.

Generation mechanism of wake galloping in two staggered circular cylinders in view of hysteretic flow phenomena

A smooth cylinder placed near the wake of an upstream smooth cylinder is susceptible to galloping. This study experimentally investigated the generation mechanism of wake galloping in two staggered cylinders of equal diameter D based on the physical flow phenomena occurring in the oscillating downstream cylinder. The horizontal center-to-center distance of the two cylinders ranged from 3.0D to 3.5D and the vertical center-to-center distance was 0.3D to 0.5D. As observed, the wind velocity range in the smooth cylinder was within the subcritical Reynolds number regime, and the unsteady responses at the downstream exhibited prominent hysteresis that evolved with the reduced velocity, and ultimately, triggered wake galloping at the critical reduced velocity. In particular, this hysteretic behavior is native to certain arrangements of the two cylinders and occurs because of the interaction between the downstream cylinder and the wake of the upstream cylinder. Moreover, the hysteresis-based discussion could identify the potential wake galloping vibrations in certain arrangements that are beyond the scope of the current investigation. With the application of 12 spiral protuberances on the surface of both cylinders, the hysteresis vanished and wake galloping was suppressed.

On a buffered threshold autoregressive stochastic volatility model

AbstractThis article introduces a new autoregressive stochastic volatility (SV) model with a new piecewise linear structure such that the regime‐switching mechanism has a buffer zone where regime‐switching is delayed. The proposed model allows us to model the hysteretic phenomenon of the regime‐switching existing on both the mean equation and the volatility equation. A full description of the proposed Markov chain Monte Carlo method is given. In the empirical study, we consider the daily closing prices of NIKKEI stock average, the exchange rate for US Dollar to Japanese Yen and Hang Seng Index. Deviance information criterion measure shows that our proposed model outperforms the classical threshold SV models.

A new type of piezoelectric self-excited vibration energy harvester for micro-actuator's energy storage

In this paper, a new type of potassium-sodium niobate (K0.5Na0.5NbO3, KNN) piezoelectric self-excited vibration energy harvester (VEH) for micro-actuator's energy storage is proposed, and the system's nonlinear dynamic characteristics are studied. The KNN piezoelectric VEH has self-excited vibration characteristics, which can convert the random vibration energy from the environment into the harmonic currents for storage. New nonlinear differential terms are introduced to describe the hysteretic phenomena of a KNN piezoelectric ceramics. The nonlinear dynamic model of a KNN piezoelectric VEH subjected to stochastic disturbance is developed, the stochastic stability of the system is analyzed, and the conditions of stochastic bifurcation are obtained. The numerical results show that the system's motions can keep periodic when the outside random excitation is not very strong. The experimental results show that the KNN piezoelectric VEH can convert the harmonic excitation to harmonic currents, and the maximum output voltage is 237.99mv; there is a certain platform in the acceleration-output voltage curves of the system, which implies that there is an optimal amplitude for excitation force; the KNN VEH can convert the narrowband excitation to the narrowband currents, and the maximum output voltage is 572.89mv; the KNN VEH successfully convert a Gauss white noise excitation to narrowband currents, and the maximum output voltage is 99.35mv. The new KNN self-excited VEH can obtain the narrowband currents from the environment, which implies a new way to obtain green energy.

Hysteretic effects and magnetotransport of electrically switched CuMnAs

Antiferromagnetic spintronics allows us to explore storing and processing information in magnetic crystals with vanishing magnetization. In this manuscript, we investigate magnetoresistance effects in antiferromagnetic CuMnAs upon switching into high-resistive states using electrical pulses. By employing magnetic field sweeps up to 14 T and magnetic field pulses up to $\sim$ 60 T, we reveal hysteretic phenomena and changes in the magnetoresistance, as well as the resilience of the switching signal in CuMnAs to the high magnetic field. These properties of the switched state are discussed in the context of recent studies of antiferromagnetic textures in CuMnAs.

Non-linear bubbly Helmholtz resonator

Microbubble clouds greatly affect the acoustic behaviour of systems such as liquid-filled Helmholtz resonators. Gas microbubbles change the resonator’s behaviour from quasi-linear to mostly non-linear, together with the appearance of hysteretic phenomena and desymmetrisation of the temporal response or a softening effect with a drop in the resonance frequencies with increasing excitation amplitudes. The aim of this study is to model the non-linear behaviour of a diphasic Helmholtz resonator filled with water containing air microbubbles. The microbubble cloud is therefore modelled with a “damped-mass-spring” second-order equation. The impact of the two phases is accounted for by considering both an equivalent stiffness and an equivalent damping value. The model is then compared to experimental data, which showed its ability to reproduce both linear and non-linear behaviour.

Unraveling the hysteretic behavior at double cations-double halides perovskite - electrode interfaces

Despite over a decade of research on metal halide perovskites (MHPs) in the context of photovoltaic applications, understanding the nature of electronic and ionic processes associated with current-voltage (I-V) hysteretic behavior has been limited. Here, we explore the hysteretic behavior in (FAPbI3)0.85(MAPbBr3)0.15 perovskite devices with lateral Cr electrodes by applying first order reversal curve (FORC) bias waveform in I-V, Kelvin probe force microscopy (KPFM) measurements, and in-situ chemical imaging by time-resolved time-of-flight secondary ion mass spectrometry (tr-ToF-SIMS). In dark, we reveal pronounced hysteretic behaviors of charge dynamics in the off-field by probing time-dependent current and contact potential difference (CPD). Under illumination, transient and hysteretic behaviors are significantly reduced. The tr-ToF-SIMS results reveal that the hysteretic behaviors are strongly associated with accumulation of Br- ions at the interfaces. In addition, the low mobility MA+ ions result in transient behavior and contribute to the hysteretic phenomena. It was shown that Pb2+ ions can be reduced at the interfaces due to electrochemical reactions with the electrode in the presence of charge injection and photogenerated charges. These hysteretic behaviors associated with charge dynamics, ion migration, and interfacial electrochemical reaction are critical to further improve the performance and stability of MHPs photovoltaics and optoelectronics.

Electroosmotic Flow Hysteresis for Fluids with Dissimilar pH and Ionic Species.

Electroosmotic flow (EOF) involving displacement of multiple fluids is employed in micro-/nanofluidic applications. There are existing investigations on EOF hysteresis, i.e., flow direction-dependent behavior. However, none so far have studied the solution pair system of dissimilar ionic species with substantial pH difference. They exhibit complicated hysteretic phenomena. In this study, we investigate the EOF of sodium bicarbonate (NaHCO3, alkaline) and sodium chloride (NaCl, slightly acidic) solution pair via current monitoring technique. A developed slip velocity model with a modified wall condition is implemented with finite element simulations. Quantitative agreements between experimental and simulation results are obtained. Concentration evolutions of NaHCO3–NaCl follow the dissimilar anion species system. When NaCl displaces NaHCO3, EOF reduces due to the displacement of NaHCO3 with high pH (high absolute zeta potential). Consequently, NaCl is not fully displaced into the microchannel. When NaHCO3 displaces NaCl, NaHCO3 cannot displace into the microchannel as NaCl with low pH (low absolute zeta potential) produces slow EOF. These behaviors are independent of the applied electric field. However, complete displacement tends to be achieved by lowering the NaCl concentration, i.e., increasing its zeta potential. In contrast, the NaHCO3 concentration has little impact on the displacement process. These findings enhance the understanding of EOF involving solutions with dissimilar pH and ion species.

A hysteretic loop phenomenon at strain amplitude dependent damping curves of pre-strained pure Mg during cyclic vibration

In this study, twins were introduced into pure Mg by pre-deformation, the strain amplitude dependent damping in pre-strained pure magnesium was investigated using cyclic vibration. The strain amplitude dependent damping curve exhibited a hysteretic loop as the strain amplitude was cycled. The damping value was greater during the high strain amplitude regime when the strain amplitude increased than when strain amplitude decreased. For the low strain amplitude regime, the opposite trend was observed. The results point to the damping behavior transitions between the two regimes occurring at a specific strain amplitude, increasing commensurately with increased pre-strain. This hysteretic loop phenomenon is attributed to the difference in mechanical energy consumed by the motion of the twin boundaries during cyclic vibration. The hysteretic loop indicates that twin dampening already exists. Therefore, the strain amplitude value of the intersection may be used as a reference parameter to detect twin damping.

A multi-objective optimization algorithm for Bouc–Wen–Baber–Noori model to identify reinforced concrete columns failing in different modes

Concrete columns are the most important load-bearing components in civil structures. The potential damage in reinforced concrete (RC) columns could be categorized into three different failure modes: flexural shear (FS) failure, flexural-failure (FF), and shear failure (SF). The corresponding hysteresis loops for each mode differ significantly. Therefore, a multi-parameter hysteretic restoring force model is needed to describe the hysteretic energy dissipation phenomenon and behavior. Identification of the optimal parameter values of a multi-parameter hysteresis model of RC columns under different failure modes is essential in the evaluation of structural inelastic seismic performance. In this paper, a multi-objective optimization algorithm called NSGA-II is employed to identify the parameters of Bouc–Wen–Baber–Noori model (BWBN) hysteresis model, this model has been used for describing the response and modelling restoring force behavior in several structural and mechanical engineering systems, that can fully describe the hysteretic restoring force characteristics of RC columns. An objective function for the restoring force is proposed to identify the parameters of BWBN model. In order to ensure the accuracy of identification, based on the sensitivity analysis, the parameters distribution law of RC columns in different failure modes is obtained. Furthermore, the reference values under different failure modes are proposed. The results presented in this paper will significantly reduce the calculation of subsequent identification. Twelve groups of experimental data are randomly selected to verify the feasibility of the above algorithm. It is demonstrated that using the multi-objective optimization algorithm leads to better identification accuracy with minimum prior experience. Performance of the algorithm is verified using simulated and experimental data. The experimental data of the RC columns were collected from the database of the Pacific Earthquake Engineering Research Center.

Collective dynamics in the presence of finite-width pulses.

The idealization of neuronal pulses as δ-spikes is a convenient approach in neuroscience but can sometimes lead to erroneous conclusions. We investigate the effect of a finite pulse width on the dynamics of balanced neuronal networks. In particular, we study two populations of identical excitatory and inhibitory neurons in a random network of phase oscillators coupled through exponential pulses with different widths. We consider three coupling functions inspired by leaky integrate-and-fire neurons with delay and type I phase-response curves. By exploring the role of the pulse widths for different coupling strengths, we find a robust collective irregular dynamics, which collapses onto a fully synchronous regime if the inhibitory pulses are sufficiently wider than the excitatory ones. The transition to synchrony is accompanied by hysteretic phenomena (i.e., the co-existence of collective irregular and synchronous dynamics). Our numerical results are supported by a detailed scaling and stability analysis of the fully synchronous solution. A conjectured first-order phase transition emerging for δ-spikes is smoothed out for finite-width pulses.