Experimental Hysteresis Research Articles

Hysteretic Dynamic Modeling and Vibration Characteristics Analysis of Metal-Rubber Isolators

A novel hysteretic constitutive model (HCM) with four parameters was proposed to reproduce the nonlinear elasticity and dry friction characteristics of metal–rubber isolators (MRIs). The HCM accurately characterized the nonlinear hysteretic behavior due to its intrinsic relationship with the geometric properties of the hysteresis loop. A physics-based parameter estimation strategy was developed to provide reasonable initial iteration values. Three MRIs with different design stiffnesses were tested to investigate their hysteretic behavior under various excitation levels. The HCM accurately reproduced the entire experimental hysteresis loops using only a subset of the experimental data. This exhibited higher precision and scalability compared to the classical dynamic model. Friction damping forces were employed to distinguish the stick-slip states of the three MRIs. Additionally, the identified parameters were used to simulate the steady-state vibration response of a complex MRI system. The resulting frequency response functions (FRFs) agreed well with the experimental data. The proposed model can effectively capture the amplitude-dependent effects in MRI systems with various design stiffnesses, enabling more accurate predictions of vibration responses.

Seismic Performance of Precast Drift-Hardening Concrete Walls Connected by Grout–Sheath Duct

In order to find a suitable size of sheath duct and a reliable construction method for precast walls, a cast-in-place and five 1/2 scale precast drift-hardening concrete walls reinforced with weakly bonded ultra-high strength SBPDN rebars were fabricated and tested under reserved lateral load and constant compression. The experimental variables were the diameter of sheath ducts (45 mm, 100 mm, and 120 mm), embedded length (20d and 35d; d is the nominal diameter of SBPDN rebars), axial load ratio (0.075 and 0.15), and the construction method. The experimental observations, hysteresis behaviors, envelope curves, residual deformation, crack propagation, and energy dissipation were compared in the study. Moreover, a formula was applied to calculate the bond strength of the sheath duct. The experimental and calculated results revealed that increasing the axial load ratio and embedment length could not enhance the bond strength of the sheath ducts, and increasing the diameter decreased the bond strength significantly. Anchored the SBPDN rebars in smaller sheath ducts separately was a more stable connection method for precast concrete shear walls and provided sufficient drift-hardening capability, even at a large drift level (over 3%).

Experimental optimization of CuO and MgO hybrid nanoparticle reinforcement ratios to enhance fatigue life of GFRP composites

AbstractThis study investigated the optimization of CuO and MgO nanoparticle reinforcement ratios within glass fiber‐reinforced polymer (GFRP) composites, and it examined the impact of the hybrid mixture of oxide powders on the mechanical properties of the GFRPs. The study aims to improve the mechanical properties of GFRPs by combining these two powerful nanofillers in various weight ratios to find the best combination to obtain the best fatigue life. Tensile‐tensile fatigue tests were conducted on 25 samples containing hybrid CuO and MgO nanoparticles ranging from 0.0 to 0.8 wt% in 0.2% increments. The test was conducted using a computer‐controlled servo‐hydraulic fatigue device. It was found that the GFRP composite reinforced with hybrid nanoparticles improved the fatigue life. The CuO proportion in the composites partially increased the brittleness properties, while the MgO proportion partially increased the stiffness according to the results. It was found that 0.6 wt% MgO–0.4 wt% CuO and 0.2 wt% MgO–0.6 wt% CuO GFRP composites demonstrated the highest fatigue life yielding at the 39.5k, and 13.7k cycle at 70%, and 80% load level, respectively. The best fatigue life was yielded at the 128k cycle with the 0.4 wt% MgO and 0.6 wt% CuO sample at the 60% load level. According to experimental hysteresis energy loss, 0.4 wt% MgO–0.2 wt% CuO GFRP composite was found to have the highest energy loss. The energy loss increased by approximately 51% in this composite compared to the non‐reinforced composite. The fracture surfaces of a fatigue sample were shown with the SEM image.Highlights The GFRP composites were produced by combining MgO and CuO as a hybrid reinforcement. Analyzed fatigue life using hysteresis curves and S–N graphs. The fatigue life of GFRP composites was improved with hybrid nanofiller content. As compared to separate reinforcements with CuO or MgO, the hybrid nanoparticle reinforcement enhanced fatigue life more.

Design, simulation and energy dissipation evaluating of a new lead shear damper

This study presents a novel design for a lead shear damper (LSD) that features lead blocks encased in laminated steel and rubber plates, intersected by X-shaped steel sticks. It combines the excellent energy dissipation and fatigue resistance of lead with the uniform yielding capabilities of X-shaped steel sticks along their height. Cyclic loading testing and fatigue tests are conducted in order to determine the mechanical properties of the LSD. The test results reveal that the LSD has a variable yielding force, and exhibits stiffness hardening when the damper's deformation direction deviates from the origin. However, when the deformation direction returns to the origin, there is no stiffness hardening observed, and the resistant force remains constant. Furthermore, this LSD can work effectively despite the failure of energy dissipation parts, which improves hysteretic energy dissipation under large deformation. In order to replicate the hysteretic behaviour, a uniaxial constitutive model is formulated and its parameters are determined by the utilization of the differential evolution approach, based on test data. The observed strong concurrence between the experimental and simulated hysteresis curves serves as compelling evidence for the efficacy of the differential evolution method. Meanwhile, a three-story building from the third-generation benchmark problem is employed as the testbed structure to examine the energy dissipation capacity of the developed dampers. Nonlinear seismic analysis on the benchmark model equipped with the proposed dampers is also conducted, and the results are compared to those fitted with conventional dampers, such as mild dampers and friction dampers. The findings of this study indicate that the performance of the LSD in reducing structural displacements is superior to that of mild dampers and friction dampers.

Evolution characteristics and performance evaluation of extended end-plate joints with single and double side connections under cyclic loading

Experimental studies were conducted on four extended end-plate joints subjected to cyclic loading at the column top, investigating the evolving patterns of the joints' mechanical performance. The paper provides a detailed analysis and discussion of the test joints' failure modes, ductility, stiffness degradation, and energy dissipation capacity. The Mann-Kendall (M − K) trend analysis tool was applied to the mechanical response curves, identifying key performance evolution points (evolution initiation point P and overall yield point Q). The trends in bolt forces, deformations, and strains at critical joints were effectively validated, revealing the transition of the energy system from quantitative to qualitative changes and the component's failure process from stability to instability. Additionally, based on the experimental joints' hysteresis curves and energy dissipation capacity, a theoretical hysteresis model was established to predict the joint's hysteresis curve and cumulative dissipated energy accurately. According to EC3 requirements, joints were classified as partially rigid connections. The experimental results of the initial rotational stiffness and plastic moment were further used to evaluate the calculated values in existing standards EN 1993-1-8, ANSI/AISC 358-16, and GB 51017-2017. The results indicate that extended end-plate connections possess sufficient strength, joint rotational stiffness, ductility, and energy dissipation capacity, making them suitable for seismic moment frames.

Damage Analysis and Startup Schedule Optimization of Steam Turbine Rotors With an Anisotropic Damage Coupled Viscoplastic Constitutive Model

Abstract The optimization of the operation scheme is of great significance for improving the flexibility of thermal power plants in energy systems dominated by renewable energy. However, thermal stress and corresponding thermomechanical fatigue damage are the main limitations. A unified viscoplastic constitutive model coupled with anisotropic damage is introduced and validated by comparing the experimental and simulated hysteresis loops and cyclic softening curves. The model is implemented into the ansys software by using the USERMAT subroutine to numerically investigate the high-temperature fatigue behavior of a 1000 MW steam turbine rotor on different startup schedules. The critical areas of the rotor are studied in terms of temperature, stress, accumulated inelastic strain, and damage. Based on the damage analysis, the hot start schedule is optimized and validated. The startup time can be significantly shortened within permitted fatigue damage. Moreover, the life expenditure under different loading-up rates is calculated and the extra startup costs can be evaluated accordingly for wider application.

Surface Spin Polarization in the Magnetic Response of GeTe Rashba Ferroelectric

We experimentally investigate magnetization reversal curves for a GeTe topological semimetal. In addition to the known lattice diamagnetic response, we observe narrow magnetization loop in low fields, which should not be expected for non-magnetic material. The diamagnetic hysteresis loop is unusual, so the saturation level is negative in positive fields, and the loop is passed clockwise, in contrast to standard ferromagnetic behavior. We show, that the experimental hysteresis curves cannot be obtained from standard ferromagnetic ones by adding/subtracting of any linear dependence, or even by considering several interacting magnetic phases. The latter possibility is also eliminated by the remanence plots technique (Henkel or \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\delta M$$\\end{document} plots). We explain our results as a direct consequence of the correlation between ferroelectricity and spin-polarized surface states in GeTe, similarly to magnetoelectric structures.

Modeling for Hysteresis Contact Behavior of Bolted Joint Interfaces with Memory Effect Penalty Constitution

A novel penalty contact constitution was developed to replicate the hysteresis memory effect observed in contact interfaces. On this basis, a refined finite element analysis (FEA) was performed to study the stick–slip friction contact behavior of bolted joint interfaces. The analysis was validated by comparing it with the experimental hysteresis loops in the literature. The simulated hysteresis loops were subsequently used to identify four parameters of the Iwan model. Additionally, the effects of bolt clamping, friction coefficient, and excitation amplitude were individually examined. It was found that the deterioration in bolt clamping performance resulted in a decrease in both the equivalent joint stiffness and energy dissipation. Similarly, the reduction in the friction coefficient yielded a comparable impact. Furthermore, the identified model parameters of critical stick–slip force and displacement exhibited a quasi-linear relationship to the bolt preload and friction coefficient.

Hybrid data-driven and physics-based simulation technique for seismic analysis of steel structural systems

This paper proposes 1) a new hybrid analysis technique by integrating a data-driven method with a physics-based technique to perform nonlinear analysis of steel structural systems under seismic loading, 2) two component-based data-driven models (PI-SINDy and DPI-SINDy) for predicting the nonlinear hysteretic response of steel seismic fuses with and without hysteretic degradation. The proposed hybrid data-driven and physics-based simulation (HyDPS) technique offers an efficient approach for seismic analysis of structures and is expected to address the challenges associated with computational cost and modeling uncertainties inherent in physics-based numerical simulations. In this technique, the well-understood components of the structure modeled numerically are combined with the critical components of the structure simulated using one of the data-driven models developed in this study. The proposed data-driven models were trained using experimental and numerical hysteresis data. The results show that these data-driven models can accurately and efficiently predict the nonlinear hysteretic response of steel structural components with and without degradation. Furthermore, the performance of the HyDPS technique powered by the PI-SINDy model is verified in the presence of noise using response history analyses performed on a steel buckling-restrained braced frame.

The effect of confinement on the phase behavior of propane in nanoporous media: an experimental study probing capillary condensation, evaporation, and hysteresis at varying pore sizes and temperatures.

Fundamental understanding of the phase behavior and properties of fluids under confinement is of great significance for multiple fields of engineering and science, as well as for many practical industrial applications. In particular, unconventional geological systems, such as shale reservoirs, possess nanometer-scale pores, which impose nanoconfinement on the fluid molecules. In large pores, the bulk phase behavior of fluids can be modeled by the well-established methods, such as equation of state (EOS) approaches. However, under confinement the thermodynamic properties of fluids deviate significantly from those in the bulk, thus rendering the traditional EOS methods ineffective in predicting the phase behavior of confined fluids. Recently, the PC-SAFT/Laplace EOS has been developed to better represent the fluid phase equilibria in nanopores, which incorporates a new parameter that needs to be determined from experimental data. In this study, a new dataset is presented to reflect the phase properties of propane confined within the MCM-41 pores, with the aim to improve both the general understanding of the phase behavior of hydrocarbons under confinement and to parameterize the PC-SAFT/Laplace EOS for the nanoconfined propane. For this purpose, propane adsorption and desorption isotherms are determined experimentally for a wide range of temperatures (-27 to 20 °C) in MCM-41 of three different pore sizes (nominal pore diameters of 60, 80, and 100 Å). The effects of temperature and pore diameter on the capillary condensation and evaporation pressures are discussed in detail. Furthermore, the adsorption-desorption hysteresis behavior and its progression for different pore sizes were discussed. The experimental data are modeled using the parameterized PC-SAFT/Laplace EOS, which accurately captured the effects of confinement on the capillary condensation of propane in MCM-41. In addition, this study enriches the field of nanoconfinement research by providing a new dataset exemplifying the thermodynamic characteristics of hydrocarbons in nanopores.

Dislocation-density-related constitutive model and its applicability to cyclic deformation and damage behavior of 316LN SS at 823 K

In the present investigation, an in-depth understanding of the relationship between dislocation kinetics and cyclic plasticity, along with the description of yield asymmetry behavior during loading and unloading in nuclear grade 316LN austenitic stainless steel at 823 K, was examined by employing a constitutive framework using the evolution of physically-based internal-state variables. The formulation encompassed a set of first-order simultaneous differential equations that governed the evolution of dislocation density, mean free path of dislocations, and back stress. These variables were interdependent with the power law which described the kinetics of plastic strain rate. The evolution equations were numerically integrated, and the simulated data were fitted to the experimental data up to stabilized cycle at a temperature of 823 K and total strain amplitudes of ±0.004, ±0.006, ±0.008 and ± 0.010. The predicted cyclic stress response as a function of the cyclic number displayed the continuous cyclic hardening from the first cycle to the initiation of stabilized cycle. Further, good agreement between the predicted and experimental hysteresis loops was found at different cycle numbers. The predicted dislocation density and tensile peak values of back/effective stress increased with cyclic hardening and approached the value of saturation at the stabilized cycle. On the other hand, a rapid decrease in mean free path with cycle number was noticed. An increase in total strain amplitude resulted in a systematic increase in dislocation density, peak stress, back stress and effective stress. At the total strain amplitudes above ±0.006, the predicted higher rates of dislocation accumulation and annihilation, and the faster evolution rate of back stress towards saturation led to the development of stable dislocation substructure configurations with a clear distinction between dislocation high/low dense regions. Furthermore, the applicability of the model was extended by including an empirical relationship between the damage variable and cycle number within the power law, thereby enabling predictions of the cyclic stress-strain response beyond the stabilized cycle.

Characterization of multi-step cyclic-fatigue hysteresis behavior of 2D SiC/SiC composite using inverse tangent modulus

Under multi-step cyclic fatigue loading, the mechanical hysteresis loops of ceramic-matrix composites (CMCs) were affected by coupled multiple damage mechanisms. In this paper, the hysteresis-based inverse tangent modulus (ITMs) was developed to characterize the cyclic fatigue mechanical hysteresis behavior in 2D SiC/SiC composite under multi-step loading. The micromechanical multi-step hysteresis constitutive models were developed for the damage state of interface partial and complete debonding. Relationships between the cyclic-dependent interface wear, hysteresis loops, interface slip damage state, and ITMs were established. Effects of multi-step peak stress level, cycle number, and interface properties on the evolution of hysteresis stress-strain curves and ITMs were analyzed. Experimental multi-step cyclic fatigue hysteresis loops and ITMs of 2D SiC/SiC composite under different peak stresses of 1.2, 1.3, 1.4, and 1.5 PLS (proportional limit stress) were predicted. Compared with other hysteresis-based damage parameters, e.g., hysteresis width, hysteresis modulus, peak and residual strain, and loops area, the damage parameter of ITMs can better reveal the interface debonding and slip damage state in CMCs under multi-step cyclic fatigue loading.

Seismic behavior and mechanism of rectangular steel-concrete composite column with three cavities

This paper proposes a rectangular steel-concrete composite column (RSCC) with three cavities, which has a good architectural function. The composite column consists of steel tubes at both ends, steel plates in the middle, and concrete in the cavity. Five RSCC with three cavities were tested to investigate the seismic performance of the column width and headed studs. It was found that the specimens all exhibited flexural damage in the form of flexural tearing of the steel tube/plate and crushing of the concrete in the steel tube cavity. As the column width increases, the load bearing ratio and the percentage of shear displacement in the middle cavity of the specimen increase. The use of headed studs in RSCC with three cavities delay the stiffness degradation of the specimens, and the ductility of the specimens with column width of 400 mm and 500 mm set with headed studs increased by 10.1% and 4.6%, respectively, compared to that of the specimens without headed studs. In addition, a finite element model of the RSCC with three cavities was established, and the finite element analysis results matched well with the experimental hysteresis curves and damage characteristics. A simplified lateral force calculation method was established, and the average error between the predicted values and the corresponding test results for each specimen was 6.1%, which verified the applicability of the calculation model and provided a reference for the engineering application of the RSCC which has good function and performance.

Micromagnetic simulation of electrochemically deposited Co nanowire arrays for wideband microwave applications

We study the magnetic properties of arrays of Co nanowires which exhibit zero bias-field ferromagnetic resonance absorptions in a 0–30 GHz range. Columnar arrays of Co nanowires with lengths of 8–15 µm were electrochemically grown using ∼20 µm thick anodic alumina membranes with 50 nm pore diameters. Microstructural, static magnetic, and microwave properties of five different nanowire arrays were characterized. The studied Co nanowires present different crystal structure textures and magnetic properties. The static magnetic loop shapes and the ferromagnetic resonance frequencies of the nanowire arrays were correctly reproduced using the Mumax3 micromagnetic software. For each sample input parameters dependent on the x-ray diffraction and microstructural data, were fine-tuned to allow the best fit of the experimental hysteresis loops and the related microwave spectra. Using this method, it was possible to analyze the rather complex interplay between geometry and magneto-structural features of the different arrays, defining which parameters play a key role in the development of nano-systems with specific microwave properties.

Identification of the scalar Preisach model with a single branch of descending hysteresis loop and numerical interpolation for the electrical steel sheet lamination with soft magnetic properties

The developed scalar Preisach model predicts the hysteresis behavior of the soft magnetic, electrical steel sheet. The experimental hysteresis loops of the electrical steel lamination prepare the Everett function required to predict the hysteresis behavior of the electrical steel lamination. We obtain the Everett function in two ways, from the series of minor loops and a single descending branch of a hysteresis loop. The Everett function has a closed algebraic form in the method using the minor loops. A genetic algorithm carries out the subsequent fitting based on the closed algebraic equation and optimization; however, the calculated flux values have highly deviated from the measured values. In another way, the Everett function consists of numerically driven Fs and B factorable functions. The values extracted from a limiting hysteresis loop determine the function Fs and B. The predicted values are correct, and the proposed method for determining the Everett function is only valid for soft magnetic materials representing symmetric and non-exchange-bias hysteresis behavior. While the method has application limitations to general magnetic hysteresis, it demonstrates the validity of using a function derived from experimentally measured hysteresis loops rather than a closed-algebraic equation to determine the Everett function. With the Everett surface the Preisach distribution function (PDF) is numerically derived and represents the difference in domain structure between two specimens.

Prediction of nature of hysteresis and hysteresis based extraction of viscoelastic material model parameters

As almost all materials exhibit viscoelastic behaviour, it is important to understand the material behaviour which would help in its application in different fields. The current research work firstly focuses on understanding the dissipating behaviour of any viscoelastic material through operator-based multi-element model from the experimental hysteresis subject to cyclic or periodic displacement loading. Genetic algorithm-based constrained optimization technique is used as an extraction technique by curve fitting. Further, the technique is used to predict the model parameters of a pig’s lumbar spinal motion segment subjected to periodic displacement loading. Following the derived model parameters, the effect of varying periodic loading on the calculated hysteresis is also compared.

Dynamic Energy Dissipation Performance of Nonlinear Large-Deformation Viscoelastic Joint Damper under Strong Dynamic Load

Large-displacement corner deformation often occurs at the joints of towering structures and long-span space structures subjected to strong earthquake. In order to improve the energy dissipation capacity of structural joints, the Nitrile Butadiene Rubber/High Abrasion Furnace Black (NBR/HAF) high damping composite was fabricated by formulation optimization in this paper, where a nonlinear large-deformation viscoelastic joint damper was proposed. The damper consists of five layers of restrained steel plates and four layers of shear energy dissipating material, which can reach 60[Formula: see text]mm shear displacement. In this paper, dynamic mechanical performance tests and static mechanical tests were firstly conducted on the core energy dissipating media of the damper. The loss factor of NBR/HAF composite reached a peak of 1.51 at about 8.2°C, while its wide damping temperature range was 27°C. Second, the accuracy of the simulation method was verified by comparing the simulated and experimental hysteresis curves. Then, the refined numerical simulation of this damper was carried out using ABAQUS finite element software with the high damping material as its core energy dissipating media. Finally, the magnitude and type of energy dissipation of each part of the viscoelastic joint damper under different loads were investigated. It was found that the large-deformation viscoelastic joint damper based on the composite had good damping capacity. Its dynamic characteristics were affected by the displacement amplitude and excitation frequency, which exhibited hardening nonlinear characteristics. As the frequency and load amplitude increased, the peak displacement in the loading direction gradually decreased, whereas the total energy input to the damper and the energy dissipated by the viscoelastic material increased monotonically. The input energy was only dissipated by the viscoelastic material, and no plastic loss occurred in the steel plate during the entire loading stage. Under high frequency and large loads, the damper can also have good energy dissipation characteristics. Because of the negative strain energy caused by plastic dilatancy, the energy dissipated by the material was gradually greater than the input energy with the load increasing.

Bond behavior of corroded reinforcements in concrete: an experimental study and hysteresis model

Bond behavior of corroded reinforcements in concrete: an experimental study and hysteresis model

Experimental study on the dynamic performance of a winding rope fluid viscous damper

This study proposed a winding rope fluid viscous damper (WRFVD) using the winding ropes to amplify the damping force of a fluid viscous damper. To investigate the dynamic performance of the WRFVD, four different prototypes were fabricated and tested under a series of sinusoidal loading protocols. Experimental results demonstrated that the WRFVD is a velocity-dependent damping device with significant and stable energy dissipation capacity. The winding rope amplification mechanism can effectively amplify the damping force of the fluid viscous damper by 3 to 6 times, and amplify the energy dissipation of the fluid viscous damper by 3.5 to 6.9 times. After 30 cycles of fatigue loading, the maximum damping force and the energy dissipation capacity of the WRFVD almost not decayed. The damping force of the WRFVD had a linear relationship with the damping force of fluid viscous damper with the coefficient of β, and β was only related to the construction of the WRFVD itself. The theoretical model of damping force based on the Maxwell-β nonlinear model could reflect the mechanical properties of the WRFVD well, and the theoretical and experimental hysteresis curves are in good agreement.

Hysteresis Behavior of Hybrid Rocking Walls: An Analytical Method

This study proposed an analytical method to predict the hysteresis behavior of hybrid rocking walls (HRWs) in the two limit states of decompression and geometric nonlinearity. The flag-shaped curve of a HRW under a given cyclic load was described using the parameters of initial stiffness, post-yield stiffness, and the energy dissipated by the wall energy dissipaters. In this method, the hysteresis loops of the wall were determined assuming no tendon yielding and concrete crushing at the wall toes. The results of the proposed analytical method were validated via experiments on two HRWs under cyclic loads and previously validated finite element models. Comparing the results of the analytical method with those of the tests and numerical models showed that the proposed method can provide acceptable predictions for the yield point, ultimate point, initial and post-yield stiffnesses, energy dissipation level in each loading cycle, as well as the hysteresis behavior of hybrid walls. This showed the efficiency and accuracy of the proposed analytical method. Moreover, despite the simplifying assumptions, the good agreement between the analytical approach and experimental hysteresis loops indicated that the role of plastic deformation in energy dissipation at the bottom of HRWs is negligible.