Hysteresis Energy Loss Research Articles

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.

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.

Exact formulation for hysteresis loops and energy loss in Stoner–Wohlfarth systems

We propose an exact expression to describe the hysteresis loops of an ensemble of Stoner–Wohlfarth particles undergoing an alternating quasi-static magnetic field. A statistical approach, which treats the quantities characterizing each particle as random variables, is adopted to get the orientation distribution of the local polarizations with respect to the applied field direction and the constitutive equation of the whole particle assembly. The hysteresis loop area gives the energy loss figure, but we have also obtained a straightforward integral expression for this quantity. The analytical relationships for the symmetric loops and the losses are successfully tested against numerical results, and the mathematical method adopted also displayed the ability to reproduce the “elemental loop” associated with any given particle of the system. While having a fundamental character, the proposed approach bears applicative interest, representing a versatile tool as the core of codes that simulate the behavior of devices employing magnetic components.

Rolling Tires on the Flat Road: Thermo-Investigation with Changing Conditions through Numerical Simulation

A crucial material comprising a pneumatic tire is rubber. In general, the tire, or more specifically, the hysteresis effects brought on by the deformation of the part made of rubber during the procedure, heat up the part. In addition, the tire temperature depends on several factors, including the inflation pressure, automobile loading, car speed, road tire, the environmental conditions, and the tire geometry. This work focuses on using simulations to calculate the temperature and generated heat flow distributions of a rolling tire with constant velocity using the finite element method. For the sake of simplicity, it is assumed that the only components of the tire are rubber, body-ply, bead wire, and the rim. While the other components are believed to be made of a linear elastic material, the nonlinear mechanical behavior of the rubber is characterized by a Mooney–Rivlin model. Investigations are conducted into the combined effects of vehicle loads and inflation pressure. Hysteresis energy loss is used as a bridge to link the strain energy density to the heat source in rolling tires, and their temperature and heat flow distributions may be determined by steady-state thermal analysis. Thanks to the state-of-the-art computing method, the time required for connected 3D dynamic rolling tire simulations is reduced. The simulation outcomes demonstrate that the maximum temperature in this paper is attained with high weights, high velocities, and low inner inflated pressures. Overall, the maximum temperature is increased with the rise of all three variables. Moreover, the rise of the friction coefficient between the tread and road surface moves the high-temperature area towards the tread/sidewall connection area.

Effects of tissue degradation by collagenase and elastase on the biaxial mechanics of porcine airways

BackgroundCommon respiratory illnesses, such as emphysema and chronic obstructive pulmonary disease, are characterized by connective tissue damage and remodeling. Two major fibers govern the mechanics of airway tissue: elastin enables stretch and permits airway recoil, while collagen prevents overextension with stiffer properties. Collagenase and elastase degradation treatments are common avenues for contrasting the role of collagen and elastin in healthy and diseased states; while previous lung studies of collagen and elastin have analyzed parenchymal strips in animal and human specimens, none have focused on the airways to date.MethodsSpecimens were extracted from the proximal and distal airways, namely the trachea, large bronchi, and small bronchi to facilitate evaluations of material heterogeneity, and subjected to biaxial planar loading in the circumferential and axial directions to assess airway anisotropy. Next, samples were subjected to collagenase and elastase enzymatic treatment and tensile tests were repeated. Airway tissue mechanical properties pre- and post-treatment were comprehensively characterized via measures of initial and ultimate moduli, strain transitions, maximum stress, hysteresis, energy loss, and viscoelasticity to gain insights regarding the specialized role of individual connective tissue fibers and network interactions.ResultsEnzymatic treatment demonstrated an increase in airway tissue compliance throughout loading and resulted in at least a 50% decrease in maximum stress overall. Strain transition values led to significant anisotropic manifestation post-treatment, where circumferential tissues transitioned at higher strains compared to axial counterparts. Hysteresis values and energy loss decreased after enzymatic treatment, where hysteresis reduced by almost half of the untreated value. Anisotropic ratios exhibited axially led stiffness at low strains which transitioned to circumferentially led stiffness when subjected to higher strains. Viscoelastic stress relaxation was found to be greater in the circumferential direction for bronchial airway regions compared to axial counterparts.ConclusionTargeted fiber treatment resulted in mechanical alterations across the loading range and interactions between elastin and collagen connective tissue networks was observed. Providing novel mechanical characterization of elastase and collagenase treated airways aids our understanding of individual and interconnected fiber roles, ultimately helping to establish a foundation for constructing constitutive models to represent various states and progressions of pulmonary disease.

Structural and thermal investigations of rolling tires in a flat road

Rubber is an essential component of a pneumatic tire. In general, the tire, or the rubber part, is heated by the hysteresis effects caused by the deformation of the rubber part during the operation. Besides, the tire temperature depends on many factors, such as inflation pressure, vehicle loading, car speed, road tire, environment condition, and tire geometry, etc. This study focuses on the finite element approach to compute by simulating the temperature distributions of a steady-state rolling tire. For simplicity, the tire is assumed to be composed of rubber, body-ply, wire, and rim only. The nonlinear mechanical behavior of the rubber is characterized by a Mooney–Rivlin model, while the other parts are assumed to be a linear elastic material. The coupled effects of the inflation pressure and vehicle loading are investigated. Hysteresis energy loss is used as a bridge to link the strain energy density to the heat source in rolling tires. The steady-state thermal analysis may obtain the temperature distribution of rolling tires. On the other hand, an efficient computational process is being introduced to decrease the time for coupled 3D dynamic rolling simulation of the tire. The simulation results show that loading is the main factor in determining the temperature field

Reduction of filler-filler interaction and hysteresis loss of carbon black filled rubber compound by using modified carbon Black

The carbon black, used in rubber compound as reinforcing filler, improves the strength, durability, and wear resistance of the rubber compound. However, it causes filler-filler interaction and results in extensive hysteresis energy losses on deformation. This research aims to reduce hysteresis energy loss of rubber compound by reducing filler-filler interaction and by improving the filler dispersion in rubber matrix. In this study, the effect of carbon black treated with benzyl tri-ethyl ammonium chloride (BTEAC) on solution styrene butadiene rubber and butadiene rubber (SSBR-BR) system was studied. Microscopic study of dispersion and distribution of carbon black in rubber matrix was performed and a significant improvement in dispersion of BTEAC treated carbon black in SSBR-BR rubber matrix was observed. As a result of increased interaction of BTEAC treated carbon black with rubber, the filler - filler interaction was significantly reduced, resulting lower hysteresis energy loss of the compound as expressed by loss tangent (tanδ) value and it has been observed that an extent of around 15% reduction in tanδ value was achieved in rubber compound consisting of BTEAC treated carbon black. In this research, the carbon black was treated with different concentration of BTEAC, such as 0.5%, 1% and 1.5% and the best balance of rubber properties was observed for 1% and 1.5% BTEAC treated carbon black.

Effect of Cold Rolling Prior to Annealing on the Grain Size-Energy Losses Relationship in a Low Carbon Grain Non-Oriented Semi-Processed Electrical Steel

In this work, the effect of cold deformation prior to annealing treatment on the microstructure and magnetic hysteresis energy losses in a low carbon grain non-oriented semi-processed electrical steel with 0.60 mm thickness was investigated. The samples were subjected to different percentages of deformation, in a range of 5–20% reduction and annealed at temperatures between 650 and 950 °C for 60 min, these were characterized by Optical Microscopy. Meanwhile the energy losses were calculated from the magnetic hysteresis loops using a Vibrating Sample Magnetometer. The experimental results showed that cold deformation increases energy losses by 50% when the steel is deformed 20%, due to microstructural defects that are introduced to the material during deformation. The presence of the microstructural defects was verified through measurements of Full Width at Half Maximum by means of X-ray diffraction. On the other hand, it was observed that annealing at temperatures below Ac1 causes only small changes in the microstructure of the steel, however, it promotes the recovery of magnetic properties by 50% with respect to the deformed material. In contrast, when the material is annealed between Ac1 and Ac3 (α+γ) magnetic properties are recovered ~33% with respect to the initial state and, at values higher than 65% compared to the state of greatest deformation (20%), as a result of both microstructural modification and the evolution of the grain size experienced by the material.

Biomechanical and Microstructural Properties of Subchondral Bone From Three Metacarpophalangeal Joint Sites in Thoroughbred Racehorses.

Fatigue-induced subchondral bone (SCB) injury is common in racehorses. Understanding how subchondral microstructure and microdamage influence mechanical properties is important for developing injury prevention strategies. Mechanical properties of the disto-palmar third metacarpal condyle (MCIII) correlate poorly with microstructure, and it is unknown whether the properties of other sites within the metacarpophalangeal (fetlock) joint are similarly complex. We aimed to investigate the mechanical and structural properties of equine SCB from specimens with minimal evidence of macroscopic disease. Three sites within the metacarpophalangeal joint were examined: the disto-palmar MCIII, disto-dorsal MCIII, and proximal sesamoid bone. Two regions of interest within the SCB were compared, a 2 mm superficial and an underlying 2 mm deep layer. Cartilage-bone specimens underwent micro-computed tomography, then cyclic compression for 100 cycles at 2 Hz. Disto-dorsal MCIII specimens were loaded to 30 MPa (n = 10), while disto-palmar MCIII (n = 10) and proximal sesamoid (n = 10) specimens were loaded to 40 MPa. Digital image correlation determined local strains. Specimens were stained with lead-uranyl acetate for volumetric microdamage quantification. The dorsal MCIII SCB had lower bone volume fraction (BVTV), bone mineral density (BMD), and stiffness compared to the palmar MCIII and sesamoid bone (p < 0.05). Superficial SCB had higher BVTV and lower BMD than deeper SCB (p < 0.05), except at the palmar MCIII site where there was no difference in BVTV between depths (p = 0.419). At all sites, the deep bone was stiffer (p < 0.001), although the superficial to deep gradient was smaller in the dorsal MCIII. Hysteresis (energy loss) was greater superficially in palmar MCIII and sesamoid (p < 0.001), but not dorsal MCIII specimens (p = 0.118). The stiffness increased with cyclic loading in total cartilage-bone specimens (p < 0.001), but not in superficial and deep layers of the bone, whereas hysteresis decreased with the cycle for all sites and layers (p < 0.001). Superficial equine SCB is uniformly less stiff than deeper bone despite non-uniform differences in bone density and damage levels. The more compliant superficial layer has an important role in energy dissipation, but whether this is a specific adaptation or a result of microdamage accumulation is not clear.

Influence of Magnetic Track Inhomogeneities on the Stability of Magnetically Levitated HTSs

The magnetization stability of a YBCO superconductor was numerically studied using the Monte Carlo method. The magnetization-reversal loops of samples with various pinning configurations (periodic and random) were calculated as well as minor loops caused by field inhomogeneities. Hysteresis energy losses were estimated via areas bounded by the minor loops at different temperatures. Samples providing a balance between the critical current, pinning properties, and energy losses, were identified. Among the considered distributions, the homogeneous (periodic) defect configurations showed the highest efficiency.

Two Approaches to the Study of Temperature Effect on the Dissipative Properties of Materials

In order to study the effect of temperature changes on the dissipative properties of materials, two approaches are used. The first approach implies introducing some temperature function under the sign of the integral in the heredity theory equation and simultaneously taking into account the dependence of the elastic modulus on temperature. As a result, based on experimental data on the thermal creep of soils, the expression for determining the hysteresis energy losses under the periodic voltage changes was obtained depending on temperature changes.According to the second approach, the expression for determining the hysteresis energy losses under isothermal conditions at different temperatures was obtained by introducing into the heredity theory equation an approximation of the experimental dependences of instantaneous deformation and temperature creep parameters for steel Kh18 N10T.

Polyacrylonitrile-Coordinated Perovskite Solar Cell with Open-Circuit Voltage Exceeding 1.23 V.

In solution-processed organic-inorganic halide perovskite films, halide-anion related defects including halide vacancies and interstitial defects can easily form at the surfaces and grain boundaries. The uncoordinated lead cations produce defect levels within the band gap, and the excess iodides disturb the interfacial carrier transport. Thus these defects lead to severe nonradiative recombination, hysteresis, and large energy loss in the device. Herein, polyacrylonitrile (PAN) was introduced to passivate the uncoordinated lead cations in the perovskite films. The coordinating ability of cyano group was found to be stronger than that of the normally used carbonyl groups, and the strong coordination could reduce the I/Pb ratio at the film surface. With the PAN perovskite film, the device efficiency improved from 21.58 % to 23.71 % and the open-circuit voltage from 1.12 V to 1.23 V, the ion migration activation energy increased, and operational stability improved.

Polyacrylonitrile‐Coordinated Perovskite Solar Cell with Open‐Circuit Voltage Exceeding 1.23 V

AbstractIn solution‐processed organic–inorganic halide perovskite films, halide‐anion related defects including halide vacancies and interstitial defects can easily form at the surfaces and grain boundaries. The uncoordinated lead cations produce defect levels within the band gap, and the excess iodides disturb the interfacial carrier transport. Thus these defects lead to severe nonradiative recombination, hysteresis, and large energy loss in the device. Herein, polyacrylonitrile (PAN) was introduced to passivate the uncoordinated lead cations in the perovskite films. The coordinating ability of cyano group was found to be stronger than that of the normally used carbonyl groups, and the strong coordination could reduce the I/Pb ratio at the film surface. With the PAN perovskite film, the device efficiency improved from 21.58 % to 23.71 % and the open‐circuit voltage from 1.12 V to 1.23 V, the ion migration activation energy increased, and operational stability improved.

Roof Deformation and Collapse of Stamps With Isolated Grooves: A Contact Mechanics Approach

Abstract This paper has revisited the roof deformation and collapse of stamps with isolated grooves based on a contact mechanics approach, with emphasis on establishing the nonadhesive and adhesive contact solutions for surfaces containing a shallow rectangular groove with the effects of applied load and interfacial adhesion taken into account. By solving singular integral equations and using the energy release rate approach, closed-form solutions are derived analytically for the deformed groove shapes, interfacial stress distributions, and equilibrium relations between load and contact size, which reduce to the previously proposed solutions without adhesion or without applied load. Finite element (FE) analysis is performed to validate the nonadhesion solutions, while experiment results of stamp collapse reported in the literature are adopted to examine the adhesion solutions. By introducing the Johnson parameter α to represent a competition between surface energy and elastic strain energy of the groove, four kinds of contact behaviors of the groove roof can be characterized appropriately: nonadhesion, weak adhesion, intermediate adhesion, and strong adhesion. Hysteresis loop and energy loss due to distinct load/unloading paths are revealed in the cases of intermediate and strong adhesion. We have also provided the critical applied pressure to achieve roof collapse and the corresponding equilibrium contact size for full range of α.

Dependence of magnetic properties with structural/microstructural parameters of ball-milled Fe15Co2P3 powder mixture

This research work aims to investigate the mechanical alloying of Fe15Co2P3 powder mixture in terms of phases’ formation, microstructural parameters, and magnetic properties as function of milling time. Parametric Rietveld refinement method, of the obtained X-ray patterns, was performed for qualitative and quantitative phase analysis alongside the determination of structural, microstructural, and mechanical properties. The ball-milled powder mixture crystallized within the face-centered cubic α-Fe(P) solid solution in equilibrium with Co75Fe25 phase. The crystallite size decreases reaching 100 and 200 nm respectively after 3 h of milling. The highest values of the dislocation density, microstrain, and stored energy are registered for the α-Fe(P) solid solution. The studied mechanical properties manifest the brittle nature of the α-Fe(P) solid solution compared to the Co75Fe25 phase. The squareness ratio Mr/Ms and the coercivity values of the milled powders increase with increasing milling time and reach steady state after 2 h. The hysteresis loss energy and maximum permeability reach minimal values of 45 × 10−4 W/m3 and 49 × 10−3 H/m respectively, after 1 h of milling at the opposite of the switching field distribution. The obtained results demonstrate the formation of nanostructured Fe15Co2P3 ternary alloy with optimum characteristics as promising candidate for diverse applications primarily in the biomedical field for diagnostics and therapeutics such as magnetic hyperthermia and vector probes for future imaging technologies.

Simulations of local field inhomogeneities of magnetic tracks and their impact on the magnetization of HTSs with defects

Using the Monte Carlo method, the full and partial magnetization loops of a YBCO superconductor have been studied. The partial loops simulated field inhomogeneities occurring on magnetic tracks in levitation systems. The influence of temperature and defect concentration on the shape and area of the full and partial hysteretic curves has been studied. The highest considered defect concentration provided the least partial curve area which meant less hysteresis energy losses and greater levitation stability.

Hysteresis Energy Loss of Nanocrystalline CoFe2O4 Synthesized by Modified Citrate-Gel Method

Hysteresis Energy Loss of Nanocrystalline CoFe2O4 Synthesized by Modified Citrate-Gel Method

Effect of sputtering power on the first order magnetization reversal, reversible and irreversible process in Fe71Ga29 thin films

We report on the first-order reversal curves (FORC) of magnetization and effect of defects on magnetization process in Fe71Ga29 thin films with different values of sputtering power (50 – 120 W). Phase purity of the thin films was confirmed by grazing incidence X– ray diffraction (GI-XRD). The reversible and irreversible contributions to the magnetization are evidenced through the minor loop parameter such as pseudo hysteresis loss (WF*) and energy loss coefficient (WF0). In particular, the energy loss coefficient is found to decrease from 28 × 106 (A/m. mT) at 50 W to 21 × 106 (A/m. mT) at 120 W, which signifies a decrease in domain wall resistance. FORC infers narrow switching, which leads to low coercivity distribution at 120 W as a result of less defects.

Low-temperature superelasticity and elastocaloric effect in textured Ni–Mn–Ga–Cu shape memory alloys

The superelastic behavior and elastocaloric effect of a [001]-textured Ni50Mn23Ga25Cu2 polycrystal have been investigated below room temperature (256–294 K). The adiabatic temperature change caused by rapid unloading of uniaxial stress reached −4.3 K at 259 K. A small stress hysteresis of 14 MPa was observed. Due to the low hysteresis energy loss (0.37 MJ m−3) stemming from the texture structure, the coefficient of performance (COPmat) of our alloy was calculated to be 18, indicating that it is a promising elastocaloric candidate for low-temperature refrigeration.

Enhancing the Elastocaloric Cooling Stability of NiFeGa Alloys via Introducing Pores

Elastocaloric cooling stability is an essential factor of solid‐state refrigeration to become a promising candidate in replacing the conventional vapor compression technology. Herein, Ni53.5Fe19.9Ga26.6 foam with 53% porosity is fabricated by a replication casting technique and its elastocaloric properties compared with Ni53Fe19.4Ga27.6 bulk alloy. NiFeGa foam expresses reversible superelasticity with strain ≈3.9% above austenite finishing temperature and also exhibits an adiabatic temperature change of 2.8 K smaller than its bulk counterpart 5.8 K. The compressive cyclic test reveals that foam shows better cyclic performance up to 100 cycles over bulk sample under the same loading effect. The enhanced cyclic stability in foam achieves due to pores and narrow hysteresis energy loss.