Hysteresis Energy Research Articles

Cyclic performance of middle partially encased composite braces

The utilization of reinforced concrete to fill the middle section of the H-shaped steel in middle partially encased composite brace (MPECB) effectively restrains the buckling deformation of the steel plates, mitigates compression instability, and enhances the compressive stiffness and bearing capacity of the brace component. To investigate the hysteresis performance and energy dissipation capacity of MPECBs, axial hysteresis tests were conducted on four MPECBs and one comparative H-shaped steel brace. The experimental results revealed that the failure mode of MPECBs involved warping deformation of flange plate and separation from the concrete. Compared to steel brace, MPECBs exhibited significantly improved energy dissipation capacity in the early loading stage, as well as enhanced compressive capacity, while showing minor change in tensile capacity. Additionally, finite element models (FEMs) were developed, and parameter analysis was performed. The FE analysis confirmed that the variations in reinforcing bars and stirrup spacing had a minor influence on the bearing capacity of MPECBs in comparison to modifications in the cross-sectional dimensions of H-shaped steel. However, reducing the stirrup spacing can enhance the utilization of the concrete in MPECB, allowing for its performance to be more effectively harnessed. Furthermore, the formula for calculating the tensile capacity of MPECB was proposed, and the design process for MPECB was summarized based on the calculation method.

Influence of structural arrangements on static and dynamic properties of additively manufactured polyester elastomer lattice metamaterials

In the current study, we present novel carbon organic framework-inspired lattice metamaterials (CFLM) with thermoplastic polyester elastomer (TPEE) to analyze the structural effects. The CFLMs (S1, S2, S3, and SS) from TPEE were successfully produced by material extrusion (MEX) via fused-filament fabrication and had never been reported previously. In the beginning stage, static compression tests were utilized to evaluate mechanical properties, densification strain, and energy absorption, which were validated using the finite element method (FEM). According to static compression results, S2 had the largest energy absorption, followed by the SS structure. In the second stage based on the static test, dynamic sinusoidal compression was performed to calculate the dynamic elastic recovery (DER), hysteresis work absorption, and Tan δ. The results showed that the proposed lattice metamaterials showed different the hysteresis energy absorption, DER, and viscoelasticity nature from Tan δ. To apply static and dynamic compression results to shoe midsoles, they were subjected to a dynamic drop weight impact test. Based on static and dynamic compression testing, including the results of dynamic drop weight impact tests, S1 was the most suitable for the toe part of the shoe midsole, whereas SS was the best for the heel part of the shoe midsole. From the overall results of all characterizations, it was concluded that the structural effect of CFLMs successfully provided different mechanical properties in the static and dynamic tests from the signal TPEE material.

The effect of pre-deformation loading on the cyclic hysteresis behavior of nanocrystalline NiTi alloy：A molecular dynamic study

In this work, the effect of pre-deformation loading on the cyclic hysteresis behavior of nanocrystalline NiTi alloy is investigated by the molecular dynamic. The nanocrystalline NiTi is subjected to a large monotonic pre-deformation loading firstly to generate the irrecoverable deformation on the initial model. After this pre-deformation treatment, the other cyclic loading is exerted on the nanocrystalline NiTi to estimate the effect of pre-deformation on cyclic hysteresis behavior. The simulation results show that the plateau length of phase transition and the hysteresis loop area decreases with the increase of pre-deformation loading. When the nanocrystalline NiTi model undergoes a pre-deformation of martensite plasticity, the hysteresis curve transforms from sigmoidal-shaped to shuttle-shaped, and the MD simulation also reveals that the hysteresis behavior is gradually dominated by the dislocation motion instead of the phase transition. The corresponding micro mechanism of this degeneration of super-elasticity could be explained by the fact that the dislocations brought by the pre-deformation hinder the reverse phase transition, which results in the accumulation of residual martensite phase and disordered structure. Furthermore, the models with different grain sizes and temperatures are also considered in the MD simulation. The simulation results proved that the dislocation motion is enhanced by the temperature increase, which brings a higher hysteresis energy under a large pre-deformation loading. For the grain size effect, the reduction of the grain size leads to a higher dislocation density, which results in a more obvious phase transition degeneration phenomenon for the model with a smaller grain size.

Seismic performance of corrugated steel plate shear walls under various constraint conditions

Corrugated steel plate shear walls (CSPSWs) support vertical or horizontal corrugated plates attached to boundary frames through two- or four-sided connections. While two-sided constraints offer better applicability and convenience, this study aims to investigate the seismic behavior of CSPSWs with both two- and four-sided constraints. The investigation considers the coupling effects of direction, aspect ratio, thickness, and axial compression ratio. The study analyzes hysteresis curves, capacity characteristics, stiffness, ductility, and energy consumption for various failure modes. The results indicate that two-sided-constrained specimens exhibit lower mechanical properties compared to four-sided-constrained specimens, especially the initial stiffness. However, both constraint types show X-shaped tension fields diagonally along the CSP under low-cycle reciprocating loading. The horizontal and vertical directions of the corrugated plates have no significant impact on the seismic performance of the four-sided-constrained system, whereas they directly affect the stiffness and lateral load of the two-sided-constrained system. Additionally, an increase in plate thickness results in greater design requirements, particularly for surrounding frame members. Furthermore, when the axial compression ratio does not exceed 0.4, the specimen exhibits good seismic performance and energy dissipation capacity.

Structural Assessment of Endodontic Files via Finite Element Analysis

A methodology for the structural assessment of Nickel-Titanium (Ni-Ti) endodontic files and a novel approach to predict their fatigue behavior using finite element method (FEM) were proposed. ProTaper-Universal F1 and F2 endodontic files were selected due to availability of extensive test data needed for the validation of the methodology. Bending and torsional loadings were analyzed since these provide essential data for the structural integrity assessment for the endodontic files. High-definition FEM models and their computationally efficient idealized versions were developed. The results for the bending and torsional stiffness of the F1 endodontic file agreed with the literature data validating the proposed methodology. Hysteresis energy density was shown to give promising results as a predictor of low cycle fatigue failure. The predictions with the idealized models matched those of the high-definition models, justifying the proposed idealizations. The validated models demonstrated that F2 has 60% higher bending and torsion resistance and 7% higher hysteresis energy density per cycle with respect to F1, leading to the conclusion that F1 has a lower structural stiffness but a longer fatigue life as compared to F2. In summary, the developed methodology allows for the structural and durability evaluation of various design parameters for Ni-Ti endodontic files.

Giant Energy Density via Mechanically Tailored Relaxor Ferroelectric Behavior of Pzt Thick Film.

Relaxor ferroelectrics (RFEs) are being actively investigated for energy storage applications due to their large electric-field-induced polarization with slim hysteresis and fast energy charging-discharging capability. Here, w e report a novel nanograin engineering approach based upon high kinetic energy deposition for mechanically inducing the RFE behavior in a normal ferroelectric Pb(Zr0.52 Ti0.48 )O3 (PZT), which results in simultaneous enhancement in the dielectric breakdown strength (EDBS ) and polarization. Mechanically transformed relaxor thick films with 4μm thickness exhibited an exceptional EDBS of 540 MV/m and reduced hysteresis with large unsaturated polarization (103.6 μC/cm2 ), resulting in a record high energy storage density of 124.1 J/cm3 and a power density of 64.5 MW/cm3 . This fundamental advancement is correlated with the generalized nanostructure design that comprises of nanocrystalline phases embedded within the amorphous matrix. Microstructure-tailored ferroelectric behavior overcomes the limitations imposed by traditional compositional design methods and provides a feasible pathway for realization of high-performance energy storage materials. This article is protected by copyright. All rights reserved.

Effect of Mg on elevated-temperature low cycle fatigue and thermo-mechanical fatigue behaviors of Al-Cu cast alloys

The effects of Mg addition on the cyclic deformation and fatigue life behaviors of Al-Cu 224 cast alloys were investigated under isothermal low cycle fatigue (LCF) at 300 °C and out-of-phase thermo-mechanical fatigue (OP-TMF) in the temperature range 60–300 °C. The results show that all tested alloys experienced cyclic softening during both LCF and OP-TMF, whereas the softening ratio of Mg-containing alloys was lower than that of the base alloy free of Mg because of the lower coarsening rate of θ'-Al2Cu precipitates. Under both LCF and TMF, near-surface porosity and brittle intermetallic particles were considered sources of crack initiation. TMF lives were inferior to LCF lives under the same strain amplitude because of the combined damage effect of the cyclic mechanical and thermal loadings. Under LCF, the addition of Mg enhanced the fatigue performance because of the co-existing θʹ and θʺ precipitates and the higher thermal resistance of θʹ; under TMF, it led to a slight reduction in fatigue performance. The hysteresis energy model was successfully applied to predict the LCF and TMF lifetimes. The predicted results agree well with the experimentally measured LCF and TMF lifetimes.

Analysis of Displacement-Controlled Fretting Between Crossed Parabolic Cylinders in Elasto-plastic Contacts

Abstract In practice, it is difficult to avoid the axis angle deviation when some regular surfaces are in micro-sliding, such as gears, machined surfaces, etc. In order to better investigate the micro-motion contact characteristics, a crossed paraboloidal contact model under frictional condition is proposed to simulate both tangential displacement-controlled fretting and the evolution of the energy dissipation in a load cycle. By deriving the theoretical of the normal and tangential contact course of the model, the load-displacement curves during initial loading, unloading and reloading stage are presented. On this basis, the hysteresis curve is then obtained by integrating the closed area surrounded by load-displacement during unloading and reloading, which also means that the empirical formulation for micro-slip in a load cycle is constructed. This study also reveals the plastic yield phenomenon under pure normal loading and plastic shakedown behavior caused by cyclic reciprocating displacement loads. In addition, the research on the junction growth, the evolution of tangential load and hysteresis curve with different COFs under multiple-cycle load is also carried out. The implications of involved parameters, such as friction coefficient, axis intersection angle, normal load and so on, are discussed with respect to hysteresis curve shape and energy dissipation. The difference about hysteresis and energy dissipation curves between the paraboloidal contact model and other classic contact models is then presented. It is discovered by comparison with other models that the paraboloidal contact model presents a relatively high energy dissipation in a load cycle.

Equivalence of Bilinear Hysteresis and Viscous Damping Energy Dissipation

Abstract To evaluate the energy dissipation differences between metal dampers and viscous dampers and to gauge the degree of equivalence between bilinear hysteresis and viscous damping, we studied the equivalence of bilinear hysteresis and viscous damping. Using a MATLAB program and the principle of equal energy dissipation, the energy dissipation effect of bilinear hysteresis was equated based on the effect of viscous damping. Under a state of sinusoidal excitation, the displacement response of the numerical method, which strictly considers the bilinear hysteresis, was compared with the displacement response of the equivalent viscous damping calculation method. The results show that the oscillation periods for the two models demonstrate high consistency, with the displacement curves in the steady-state response stage nearly identical. Because of the lag in hysteresis energy dissipation, the bilinear hysteresis system always reaches the steady-state stage slower than the equivalent viscous damping system, implying that the metal damper responds more slowly to transient energy. In the free vibration stage, the bilinear hysteresis system cannot return to the initial position, while the displacement of the equivalent viscous damping system approaches zero, suggesting that the self-resetting effect of the viscous damper is better.

Influence of microphase separation and crosslinking density on dynamic viscoelastic properties of nano‐Fe3O4 modified polyurethane

AbstractAlthough there have been some studies on the preparation and characteristics of nano‐Fe3O4‐filled polyurethane (PU) composites, research focusing on the quantitative influence of the degree of microphase separation (DPS) and the crosslinking density (CLD) on dynamic viscoelastic properties is rare. In this paper, PU composites are synthesized by incorporating nano‐Fe3O4 as fillers. The dynamic mechanical properties under alternating loads are investigated using dynamic mechanical analysis. The influences of the DPS and the CLD on the dynamic hysteresis loss are analyzed. The experimental results show that the DPS and CLD of PU nanocomposites increase and then decrease with the increase of nano‐Fe3O4 addition and reached a maximum at the addition amount of 1.0 wt%. The quantitative relationships between DPS, CLD and the dynamic hysteresis loss of PU nanocomposites at different filler ratios are obtained. With a 1.0 wt% nano‐Fe3O4 content, the strain energy density (SED) and hysteresis energy density (HED) are increased by 416% and 354%, respectively. The hysteretic loss H indexes of all composites are kept lower than that of pure PU. These characteristics make nano‐Fe3O4‐filled PU a promising material for reducing the rolling resistance and increasing the service life of fuel‐saving tire materials.

Mechanical Properties of 6061 Aluminum Alloy under Cyclic Tensile Loading

During the service process of an aluminum alloy structure, its complex deformation zone experiences repeated loading problems such as repeated tension, compression, bending and reverse bending. At the same time, the cyclic loading and heat treatment process also have a certain impact on the mechanical properties of aluminum alloy extruded tubes. Therefore, the study of heat treatment process parameters has important engineering and practical value for the mechanical properties of aluminum alloy extrusion tubes under cyclic loading conditions. The experiment takes 6061-T6 aluminum alloy extruded tubes as the research objects. In the study, heat treatment and cyclic tensile tests were carried out on 26 aluminum alloy specimens to study the effects of different heat treatment parameters (such as heating temperature, holding time, and cooling method) on the stress–strain hysteresis curves, stress characteristics, hysteretic energy, skeleton curves and failure characteristics of the alloy under the same loading system. In addition, different cyclic tensile tests were carried out on 20 aluminum alloy samples without secondary heat treatment to discuss the effects of different cyclic loading regimes on the mechanical properties of the alloy. The research results indicate that the effect of heating temperature on the cyclic loading performance of the alloy is greater than that of the holding time, and the effect of the cooling method on the cyclic loading performance of the alloy is not obvious. A cyclic tensile loading regime has a significant impact on the strength, elongation and hysteresis energy of the alloy. The hysteretic behavior of the alloy during cyclic tensile loading depends on the applied stress level and loading history. As the number of cycles increases, the shape of the hysteresis curve tends to be stable, but there is no monotonic relationship between the number of cycles loaded and the hysteresis energy.

Numerical assessment of an enhanced stiffened extended end-plate joint for composite frame structures

This paper presents the numerical assessment of a novel enhanced Bolted Stiffened Extended End-Plate (BSEEP) connection for steel frames with composite beams and H-shaped columns in the strong direction. Strain demand is a critical local response that directly controls rupture initiation, and it is more crucial in composite beams since the neutral axis shifts upwards due to the composite action. The proposed connection, called URBS-BSEEP, employs a reduced section in the beam upper flange to mitigate the strain demand problem and provide a stable and symmetric plastic hinge in the desired location. Nonlinear FEM is employed to study joint cyclic behavior. Eleven specimens are designed to compare the proposed connection with existing configurations and to investigate the effects of the slab isolation from the column, shear stud removal, reduced section geometry, and slab thickness. Hysteresis curves, ductilities, failure modes, strain profiles, and energy dissipation capacities are compared. The results indicate the superior performance of the connection compared to the conventional counterparts.

Experimental study on seismic performance of thin-walled steel-straw board composite walls with built-in steel plate

Based on the original cold-formed thin-walled steel (CFS)-straw board composite wall, CFS-paper straw board-steel plate composite wall is proposed as a new type of composite wall. To examine the seismic performance of this type of wall, cyclic loading tests were conducted on seven wall specimens to investigate their hysteresis curves, skeleton curves, shear capacity, displacement, lateral stiffness, ductility, and energy dissipation coefficient. The key parameters of the specimens were as follows: with or without a steel plate, built-in/external steel plate, steel plate thickness, and single-sided or double-sided layout of steel plates. Experimental results show that the addition of steel plates can improve the shear capacity and lateral stiffness of composite wall. Walls with steel plates of the same thickness placed on the inside have higher shear capacity, lateral stiffness, ductility, and energy dissipation performance than those placed on the outside. The shear capacity of a composite wall with double-sided steel plates is higher than that of a wall with single-sided steel plates. Increasing the steel plate thickness can improve the bearing capacity and lateral stiffness; however, the increase in shear capacity does not have a linear relationship with thickness. Finite element analyses were performed on the specimens to investigate the influence of other factors on the shear capacity of composite walls. Finally, the shear force flow calculation method was used to derive the shear bearing capacity of composite walls. The results of the shear capacity calculation formula derived based on the failure of the self-tapping screw connection compared with experimental values were found to be accurate.

Bending restoring force model of angle-steel reinforced concrete columns under combined torsion

To explore the restoring force model of an angle steel truss reinforced concrete column (ASRC) under the combined action of compression, bending, shear, and torsion, nine ASRC columns under a combined torsion environment were tested and analyzed. This study observed and summarized the failure mode characteristics of different component columns, distinguished different failure modes, and analyzed the hysteresis curve and energy dissipation capacity of component columns. Then, a trilinear skeleton curve model suitable for ASRC columns is adopted, and the calculation method of skeleton curves in different stages under the combined action of compression, bending, shear, and torsion is given. Finally, the ASRC hysteresis rule is simplified, and fitting produces the formulae for positive and negative hysteresis curve unloading stiffness. The restoring force model of the ASRC column under coupled torsion is established, and the test results validate the restoring force model. The results show that the established restoring force model can predict the hysteretic behavior of ASRC under combined torsion. This research can be used as a theoretical foundation as well as an experimental reference for the technical use of ASRC.

Finite-Element Analysis on Energy Dissipation and Sealability of Premium Connections under Dynamic Loads

In the process of high flow rate fracture and high gas production, the sealing performance of the premium connection decreases due to the dynamic load and vibration of downhole tubing strings, which may cause accidents. Existing static analysis methods cannot effectively explain this phenomenon. The main objective of this paper is to propose a novel analytical method for evaluating the sealing performance of a premium connection. In this paper, a dynamic model of sealing surfaces of the premium connection is established based on the vibration equation of elastic rod, and the hysteresis characteristics and energy dissipation mechanism of sealing surfaces are analyzed. Considering the influence of spherical radius, internal pressure, axial cyclic load amplitude, and modal vibration, a spherical-conical premium connection finite element model is established to analyze the influence laws of the connection’s energy dissipation and sealing performance. The results show that the sealing performance of the premium connection under dynamic load can be effectively analyzed by using energy dissipation theory compared with traditional static contact analysis. Compared with the vibration of the tubing string, the dynamic loads caused by the change of fluid pressure and flow rate in the tubing string have a significant influence on the connection’s sealing performance. When the internal pressure and axial cyclic loads are 80 MPa, 400 kN, or 60 MPa and 500 kN respectively, serious plastic deformation occurs in the thread and sealing surfaces, and the energy dissipation of the sealing surfaces increases significantly, which could lead to sealing failure.

The Measurement and Analysis of the Hysteresis Loss in a Multifilament MgB2 Superconducting Wire

The article presents the results obtained from measuring the magnetization of and hysteresis loss in a multifilament MgB2 superconducting wire (produced by ASG Superconductors) for magnetic field applied in two directions: in parallel and perpendicular to the conductor axis. The measurement temperatures were varied in the range of 5–45 K. The MgB2 superconducting fraction magnetization curves were obtained by subtracting the magnetization of the wire ferromagnetic matrix measured at temperature T = 45 K, which is above the superconductor critical temperature Tc , from the magnetization value of the entire specimen. From these magnetization curves, the dependences of the hysteresis energy loss on the external magnetic field strength Qh(Н) were obtained. It is shown that, with the field oriented perpendicular to the MgB2 wire axis and at the external field characteristic values, the hysteresis loss is twice as large. A method for calculating the hysteresis loss in a superconducting wire and methods for reducing it are proposed. The obtained results can be used to optimize NMR and MRI facilities, superconducting motors and generators made using MgB2 superconducting wire produced by ASG Superconductors.

Seismic performance of corroded non-seismically and seismically detailed RC beam-column joints rehabilitated with High Strength Fiber Reinforced Concrete

The experimental investigation was undertaken to restore the seismic performance of the corrosion-damaged beam-column joint (BCJ) rehabilitated with High Strength Fiber Reinforced Concrete (HSFRC). A total of eight exterior beam-column sub-assemblages were cast following two types of reinforcement detailing as per IS 456:2000 and IS 13920:2016, respectively. Three specimens from each reinforcement detailing regime were subjected to three different levels of corrosion and thereafter rehabilitated with HSFRC. The hysteresis behavior, energy dissipation, stiffness degradation, crack patterns, and damage index of all rehabilitated specimens are analyzed and compared with the conventional specimens. Test results indicate that the replacement of damaged concrete with HSFRC can recover the strength of corrosion-damaged BCJ when the corrosion ratio is within 10 %. The peak load-carrying capacity and initial stiffness of rehabilitated specimens showed a significant increase up to 36 % and 84 % respectively, when compared to control specimens. The ductile detailing rehabilitated specimens showed up to 90 % higher equivalent viscous damping ratio than the non-ductile ones, exhibiting close stirrups arrangement superiority. Despite recovering the load-carrying capacity at initial drifts, the seismic performance of non-ductile and ductile rehabilitated specimens having 17.76 % and 20.32 % corrosion ratio were not recovered at higher drifts.

Quasi-static cyclic test on seismic performance of steel reinforced concrete frame with replaceable energy-dissipating member

In view of damage controlling and earthquake-resilient performance, the steel reinforced concrete (SRC) frame with replaceable energy-dissipating member (REDM) is proposed. The REDM is consisted of high damping concrete (HDC) wall panel and several fuses made by low yielding-point (LYP) steel. At first, low-cyclic reversed loading test on fuse is carried out to explore its shear capacity and hysteretic behavior. The suitable dimension and shape of fuse is determined for further study. Then the quasi-static cyclic test considering two loading patterns is applied on two SRC-REDMs. One specimen is loaded until overall failure while another is repaired by installing a new set of REDM during the loading history. The analyses and comparisons are conducted in terms of failure mode, yielding pattern, hysteretic characteristics, stress distribution, stiffness degradation, dynamic characteristics, ductility and energy dissipation. The failure mode is summarized as bending-shear failure of the wall panel, local buckling of fuses and beam hinge failure mechanism of SRC frame. The hysteretic loops are plump while large energy dissipation capacity is represented. The seismic performance is verified by high bearing capacity and ductility. The bearing capacity and stiffness of repaired specimen is significantly rehabilitated. The new REDM has dissipated much more hysteresis energy than that of non-repairing case. The earthquake-resilient behavior is confirmed by the significant recovery in mechanical properties.

Energy‐Efficient Operation Conditions of MoS2‐Based Memristors

Sufficient energy consumption for conventional information processing makes it necessary to look for new computational methods. One of the possible solutions to this problem is neuromorphic computations using memristive devices. Memristors based on molybdenum disulfide () are a promising way to provide a sizeable amount of hysteresis at low energy costs. Herein, different configurations of memristors as well as the mechanisms involved in hysteresis formation are shown. Bottom gated configuration is beneficial in terms of hysteresis area and energy efficiency. The impact of device channel dimensions on the hysteresis area and energy consumption is discussed. Different operation conditions with triangular, rectangular, sinusoidal, and sawtooth drain‐to‐source pulses are simulated, and rectangular pulses demonstrate the highest energy efficiency. The study shows the potential to realize low‐power neuromorphic systems using memristive devices.

Parametric analysis on the lateral force resistance of Qing Dynasty timber frame containing stacked purlins

In ancient wooden structures of the Qing dynasty in China, stacked purlins are important longitudinal elements. In this study, a refined finite element model of a four-column timber frame containing stacked purlins was built. The effects of the fangs, spacer boards, and purlins with dovetail ends on the lateral resistance of the timber frame and the mid-span vertical deflection of the purlins were studied. The longitudinal hysteresis curve of the timber frame made up of stacked purlins was found to be S-shaped, centrally symmetrical, with a pinching effect and full at both ends. The Fangs made the greatest improvement on the lateral stiffness, displacement ductility, and total hysteresis energy consumption of the timber frame by reducing the mid-span vertical deflection of the purlins. The spacer boards contributed less to the lateral resistance of the timber frame than Fangs, but they contributed most to the reduction of the mid-span vertical deflection of the purlins. The dovetail connection at the ends of the purlins had a limited effect on reducing the lateral stiffness and ductility of the timber frame and increasing the mid-span vertical deflection of the purlins, but they significantly increased the total energy consumption of the timber frame and its energy consumption capacity.