Explore the vast range of titles available.

The dynamic response and bifurcations of high-dimensional systems endowed with hysteretic restoring forces in all degrees of freedom are investigated. Two types of hysteresis models are considered, namely the Bouc–Wen model and a differential version of the so-called exponential model of hysteresis. The numerical technique tailored for tackling high-dimensional hysteretic systems is based on an enhanced pathfollowing approach based on the Poincaré map. In particular, a five-dof mass-spring-damper-like system, with each rheological element described by the Bouc–Wen or the exponential model of hysteresis enriched by cubic and quintic nonlinear elastic terms, is investigated and a rich variety of nonlinear responses and bifurcations is found and discussed.

This paper studies the properties of the Preisach model and the play model, and compare their similarities. Both are history-dependent hysteresis models that are used to model magnetic hysteresis. They are described as discrete sums of simple hysteresis operators but can easily be reformulated as integral equations of continuous distribution functions using either a Preisach weight distribution function or a play distribution function. The models are mostly seen as phenomenological or mathematical tools but can also be related to friction-like pinning of domain-wall motions, where Rayleigh’s law of magnetic hysteresis can be seen as the simplest case on either the play model or the Preisach model. They are poor at modeling other domain behavior, such as nucleation-driven hysteresis. Yet another hysteresis model is the stop model, which can be seen as the inverted version of the play model. This type of model has advantages for expressions linked to energy and can be related to Steinmetz equation of hysteresis losses. The models share several mathematical properties, such as the congruency property and wiping-out property, and both models have a history of dependence that can be described by the series of past reversal points. More generally, it is shown that the many models can be expressed as Preisach models, showing that they can be treated as subcategories of the Preisach type models. These include the play model, the stop model and also the alternative KP-hysteron model.

History-dependent hysteresis models can potentially describe magnetization curves of all orders accurately. This property is essential for modeling magnetization and power loss in magnetic components subjected to distorted excitation waveforms, which result in complex magnetization patterns such as offset minor loops. The basic Zirka–Moroz history-dependent hysteresis model offers a good balance between the model’s complexity and accuracy. However, estimating the model’s parameters can be challenging. This research provides insight into the parameter estimation procedure for the discussed hysteresis model. Based on the measured first-order reversal curves, the fundamental two-step parameter estimation procedure was employed and analyzed for two non-oriented and one grain-oriented electrical steel types used widely in contemporary electric drives and electromagnetic devices. For each sample evaluated, two sets of parameters were estimated and compared to the reference parameters recommended for non-oriented electrical steels. The performed analysis is essential for gaining a comprehensive understanding of the capabilities, challenges, requirements, and limitations associated with estimating the parameters and performance of the analyzed model for specific electrical steel types.

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.

Cyclic tests are conducted on interlinked reinforcing bar coupler-box assemblies, adopted to retrofit buckled reinforcing bars at the plastic hinge locations of columns in multi-storied reinforced concrete building frames. The efficacy of the proposed retrofitting technique is evaluated by comparing the hysteresis behavior, computed parameters of performance index, and failure mechanism of the reconstructed frame with the original frame. An energy-based strength deterioration hysteresis model is developed on the basis of cyclic test results for analytically computing the post-yield behavior of retrofitted reinforced concrete (RC) frame with the proposed coupler-box assembly. The experimental test results manifest that the coupler-box assembly can be a promising futuristic approach for seismic retrofitting of severely damaged reinforced concrete buildings, where buckling of longitudinal reinforcing bars at the plastic hinge location of columns is inevitable, and the process of restoration is challenging under existing gravity loads. The suggested retrofitting mechanism restrains the section from any movement against rotation and helps in shifting the yield location of reinforcing bars. The main advantage of adopting the coupler-box is that there is no observed slip of reinforcing bar from the sleeve, and the entire retrofitted section remains intact even after a lateral storey drift of 6%, which is larger than the collapse prevention drift level of 4% as per Federal Emergency Management Agency guidelines. Keywords: coupler-box assembly; deterioration strength hysteresis model; energy dissipation; hysteresis behavior; reinforcing bar coupler sleeve; seismic retrofitting.

Piezoelectric actuators are widely used in the field of micro- and nanopositioning due to their high frequency response, high stiffness, and high resolution. However, piezoelectric actuators have hysteresis nonlinearity, which severely affects their positioning accuracy. As the driving frequency increases, the performance of piezoelectric actuators further degrades. In addition, the impact of force on piezoelectric actuators cannot be ignored in practical applications. Dynamic hysteresis with force-voltage coupling makes the hysteresis phenomenon more complicated when force and driving voltage are both applied to the piezoelectric actuator. Existing hysteresis models are complicated, or inaccurate in describing dynamic hysteresis with force-voltage coupling. To solve this problem, a force-voltage-coupled Prandtl–Ishlinskii (FVPI) model is proposed in this paper. First, the influence of driving frequency and dynamic force on the output displacement of the piezoelectric actuators are analyzed. Then, the accuracy of the FVPI model is verified through experiments. Finally, a force integrated direct inverse (F-DI) compensator based on the FVPI model is designed. The experimental results from this study show that the F-DI compensator can effectively suppress dynamic hysteresis with force-voltage coupling of piezoelectric actuators. This model can improve the positioning accuracy of piezoelectric actuators, thereby improving the working accuracy of the micro- or nano-operating system.

The vibratory roller’s compaction in the initial and middle stages is crucial for transforming loose subgrade filler particles into a dense state. The subgrade shows nonlinear characteristics of large and small plastic deformation. To describe these nonlinear characteristics, a new nonlinear model of vibratory roller-soil coupling is proposed. Initially, a two-degree-of-freedom model of the vibrating roller-subgrade system is established, considering the subgrade’s vibration. A small parameter is introduced to improve the elastic element of the frame shock absorber and the subgrade’s nonlinear hysteresis model. The analytical solution of the proposed nonlinear dynamic equation is solved and verified by the numerical solution. Subsequently, the vibrating wheel’s nonlinear dynamic responses are studied, including time-frequency domain, Poincare section, and bifurcation diagrams. It is found that during the initial stage, increasing excitation frequency or decreasing excitation force causes the vibrating wheel’s response to shift from “double period” to “single period.” In the middle stage, the vibrating wheel’s motion exhibits three states: “chaos,” “double period,” and “single period.” These nonlinear vibration response characteristics provide a theoretical foundation for selecting intelligent compaction parameters.

The hysteresis model can be used to accurately predict the magnetic hysteresis characteristics of ferromagnetic materials. Incorporating the hysteresis model into finite element calculations enables precise prediction of field distributions, voltage or current variations in circuits, and losses, which is essential for electromagnetic transient analysis involving remanent magnetization. When incorporating the hysteresis model into finite element analysis, prohibitively small time-steps are required to resolve hysteresis loops, leading to excessive simulation times compared to simplified BH curve approaches. Furthermore, numerical instabilities arise near zero-crossing points of magnetic flux density, where erroneous negative differential reluctivity values may lead to the divergence of the nonlinear solving process. A finer time resolution needs to be utilized to ensure the convergence of the nonlinear solver. This leads to more time-steps and longer computational time. This work proposes a localized stabilization strategy for regulating the differential reluctivity in instability-prone regions of the hysteresis loop, which can stabilize the nonlinear iteration while avoiding the local refinement of time resolution and thus reduce the overall computation time.

Piezoelectric actuators are widely used in micromanipulation and miniature robots due to their rapid response and high repeatability. The piezoelectric actuators often have undesired hysteresis. The Prandtl–Ishlinskii (PI) hysteresis model is one of the most popular models for modeling and compensating the hysteresis behaviour. This paper presents an alternative digitized representation of the modified Prandtl–Ishlinskii with the dead-zone operators (MPI) hysteresis model to describe the asymmetric hysteresis behavior of piezoelectric actuators. Using a binary number with n digits to represent the classical Prandtl–Ishlinskii hysteresis model with n elementary operators, the inverse model can be easily constructed. A similar representation of the dead-zone operators is also described. With the proposed digitized representation, the model is more intuitive and the inversion calculation is avoided. An experiment with a piezoelectric stacked linear actuator is conducted to validate the proposed digitized MPI hysteresis model and it is shown that it has almost the same performance as compared to the classical representation.

In order to study the effect of both longitudinal reinforcement and stirrups corrosion on the bond performances at steel–concrete interface under reversed cyclic loading, in this paper, the eccentric pull-out tests under reversed cyclic loading were carried out on reinforced concrete (RC) specimens with five corrosion degrees, three concrete cover thicknesses, and three stirrup spacings. The influence of the corrosion rate of longitudinal reinforcement, corrosion rate of stirrups, cover thickness, and stirrup spacing on bond performance indicators was examined, including the initial bond stiffness, peak bond stress, slip at peak bond stress, bond strength at unloading, unloading stiffness, frictional bond resistance, and cumulative energy dissipation. Moreover, the effects of coupling corrosion on cover cracking morphology and bond degradation mechanism were also analyzed. Results indicated that after severe corrosion of longitudinal reinforcement and stirrups, the cover appears cracking or local spalling, and the bond performances are significantly reduced. It was also showed that thickening cover or densifying stirrups could improve the interface bond performance and energy dissipation capacity. Each hysteresis parameter degrades apparently under the controlling slip corresponding to the peak bond stress. Subsequently, based on the analysis results and previous studies, empirical local bond stress-slip hysteresis models for corroded longitudinal reinforcement and corroded stirrup under reversed cyclic loading were proposed. Good consistency was observed for the hysteresis model with existing experimental data.