Effect Of Energy Dissipation Research Articles

Self-Centering of RC Columns with Prestressed Fe-SMA Reinforcement

Severe seismic events often lead to detrimental residual displacements in traditional monolithic bridge columns, resulting in serviceability issues and substantial repair costs. Conversely, post-tensioned segmental columns display beneficial self-centering behavior and minimal residual drifts owing to the post-tensioning force and rocking behavior at segment joints. Despite these advantages, such structures exhibit limited energy dissipation capacities and require heavy mechanical equipment for prestressing through conventional tendons. This paper discusses the feasibility of using prestressed Fe-SMA reinforcement for self-centering of existing and new bridge columns. Firstly, the results of an experimental study on the self-centering of existing monolithic columns are presented, followed by a numerical study on the feasibility of using Fe-SMA for the self-centering of segmental columns. A 3D finite element (FE) model, developed in ABAQUS, was validated against experimental results to evaluate the seismic performance of the proposed column system. The validated model was then utilized for a focused investigation into the influence of the ratio of energy dissipating (ED) bars to Fe-SMA bars, bond condition of Fe-SMA bars, and concrete confinement of segments on the self-centering and energy dissipation behavior of prestressed segmental columns. The results highlight the ability of Fe-SMA bars to provide effective self-centering and energy dissipation for existing and new bridge columns due to their self-prestressing and high ductility.

Fabrication of a tough, long-lasting adhesive hydrogel patch via the synergy of interfacial entanglement and adhesion group densification.

Adhesive hydrogels (AHs) are considered ideal materials for flexible sensors. However, the lack of effective energy dissipation networks and sparse surface polar groups in AHs lead to poor mechanical properties and interfacial adhesion, which limit their practical application. Herein, a tough, long-lasting adhesive and highly conductive nanocomposite hydrogel (PACPH) was fabricated via the synergy of interfacial entanglement and adhesion group densification. PACPH was obtained by the in situ polymerization of highly carboxylated cellulose nanocrystals (SCNCPA, surface pre-grafted polyacrylic acid chains, C-COOH = 11.5 mmol g-1) with the acrylic acid precursor. The unique tacticity of SCNCPA provides strong interface entanglement and multiple hydrogen bonds with the PACPH network, which further increases the energy dissipated during SCNCPA displacements, and enhances the mechanical properties of PACPH (tensile strength = 1.45 MPa, modulus = 332 kPa, and fracture toughness = 13.2 MJ m-3). Meanwhile, SCNCPA increases the density of surface polar groups in PAPCH and also acts as an anchor point to improve the adhesion strength (>2-3 times) of PACPH on various substrates. The combination of excellent mechanical, adhesive, and conductive properties of the PAPCH-integrated patches enables long-term monitoring of human daily activities and electrocardiogram (ECG) signals, verifying that PAPCH is a promising material platform for the further development of flexible sensors and other health management devices.

Numerical simulation of collision dynamics between a dry particle and a liquid-coated wet particle

A comprehensive understanding of wet particle collisions in the presence of a liquid film is essential for industrial processes. In this study, we conduct a numerical investigation into the dynamics of both normal and oblique collisions between a dry particle and a liquid-coated wet particle. In normal collisions, the gas flow velocity near the stretching liquid bridge increases significantly, while oblique collisions exhibit no such increase. The wetting area of particles reaches its maximum when solid particles come into contact, at which point the viscous and capillary forces acting on the particles also reach their peaks. The capillary force causes kinetic energy dissipation to be one magnitude greater than viscous energy dissipation. The normal wet restitution coefficient rises with the logarithm of the modified Stokes number, reflecting energy dissipation effects. As the collision angle increases, the normal wet restitution coefficient gradually increases and surpasses the tangential wet restitution coefficient.

Direct Observation of Contact Electrification Effects at Nanoscale Using Scanning Probe Microscopy

AbstractIn the last decade, contact electrification has gained attention for its potential in energy harvesting, addressing fundamental physics. Scanning probe microscopy (SPM) has evolved as a powerful platform, enabling the in situ characterization/manipulation of a sample's tribological/electrical properties at nanoscale. However, although both the sliding and tapping modes are available in the energy harvesting, the lateral sliding using contact mode SPM has predominantly been employed in triboelectric study. In this work, contact electrification on polydimethylsiloxane is investigated, using peak force tapping atomic force microscopy (PF‐AFM). As PF‐AFM quasi‐discretely offers vertical tapping motions of the probe with a regulated force amplitude, resembling a vertical‐type triboelectric nanogenerator, while minimizing lateral forces. The subsequent surface potential measurements reveal that the generated tribocharge is influenced by both the effective work function difference and energy dissipation at the interface. Furthermore, the accumulation of transferred charges is explored by measuring tip‐sample current during the PF‐AFM operation, showing the comparable results with the surface potential measurement. The results can be attributed to the contact potential difference assisted by the energy dissipation at the interface. This study offers an advanced opportunity to understand and study charge generation behavior based on surface properties without damaging the sample.

Characterizing the nonlinear behavior of viscoelastic materials: A Bayesian approach combining oberst beam experiments and digital-twin simulations

Viscoelastic materials are widely utilized in engineering for their advantageous damping properties, which enable effective energy dissipation. They are also valued for their stiffness properties, particularly in the case of suspension design. The behavior of these materials is complex, making it challenging to accurately incorporate them into simulations. If the dependence of dynamic properties on frequency and temperature has been commonly investigated, other phenomena still need to be studied, as for instance nonlinear phenomena leading to changes with the magnitude of stress/strain. Amongst them, the Payne effect, which manifests itself by a monotonous decrease of the storage modulus, remains difficult to integrate in the simulations, and is not often characterized experimentally for vibration purposes. An approach is proposed to identify the Payne effect by combining tests derived from the Oberst beam set-up and numerical simulations. To take into account the uncertainties inherent to the experiments, the identification process is based on a Bayesian identification framework which allows to determine the parameters and their statistical properties from a limited number of experimental measurements. The coupling between the Bayesian identification of dynamic properties of a polymer sample and a digital twin of the experimental set-up allows to identify the evolution of the storage modulus as a function of the strain amplitude, as well as the confidence interval around the mean value. The application on a silicone sample confirmed the decrease of the modulus with the strain level, with a good confidence level. The methodology developed here for the specific case of the Payne effect can be extended more generally to the experimental characterization of nonlinear behavior.

Design and hydraulic performance of bionic leaf vein‐type drip irrigation emitters

AbstractTo improve the hydraulic performance of leaf vein drip irrigation emitters, a combination of a genetic algorithm and numerical simulation was used to investigate the hydraulic characteristics of the model. The minimal flow index is used as the optimization objective to obtain the best design parameters for the flow channel structure. The results show that the leaf vein drip irrigation emitter has a flow index of 0.53, and the structural loss coefficient of the leaf vein drip irrigation emitter is 64.5–70.9 under 50 kPa working pressure, with a good energy dissipation effect. Among the design variables, the flow index (denoted as x) was influenced in the following order: the width of the unit structure f had the largest impact, followed by the vertical distance from the front baffle c, the inlet width a and the length of the unit structure h. The flow index x exhibited a positive correlation with the inlet width a, the vertical distance from the front baffle c and the length of the unit structure h, while it displayed a negative correlation with the width of the unit structure f. The correlation coefficient between the simulated and measured results was 0.994, with an average error of 2%, and the accuracy of the simulation results was high. Notably, the absence of noticeable low‐velocity vortices at the corners and confluence of the leaf vein flow channel indicated excellent resistance to blockage.

Substrate dependent cracking behavior of CrAlN coatings

SummaryThe present study investigated the effect of substrate deformation behavior on crack resistance of CrAlN coatings under quasi‐static and cyclic loads using nanoindentation. (Cr47Al53)N coatings were deposited on cemented carbide WC‐Co and high‐speed steel HS652C substrates through physical vapor deposition (PVD) und characterized. In order to study the coating cracking behavior, the coated substrates were subjected to quasi‐static nanoindentations with indentation force Fmax = 1 N, Fmax = 1.5 N and Fmax = 2 N. Moreover, the crack resistance under cyclic loading with frequency f = 0.16 Hz was analyzed at F = 1 N and F = 1.5 N after n = 900 cycles. A conical diamond indenter was used for the tests. At the end, the indentation imprints were analyzed by scanning electron microscopy (SEM). The substrate dependency was apparent in cracking behavior of the coating. Albeit the lower indentation depth compared to the variant with HS6‐5‐2C substrate, the CrAlN coating on WC‐Co substrate showed surface cracks under quasi‐static and cyclic loading. These cracks on the coated surface were absent in the variant with HS6‐5‐2C substrate. This could be related to higher resistance of cemented carbide substrates against plastic deformation, prompting earlier crack initiation in CrAlN coating for effective energy dissipation during indentation.

A novel low-voltage responsive NIPAAm/CNTs/Fe(phen)3 double network shape-changing hydrogel with a balance between mechanical properties and deformation ability

The trade-off of electro-induced shape-changing hydrogels (EISCHs) between mechanical properties and deformation ability limited its further applications. In this work, the double network technique of reinforcing nondeformable hydrogels’ mechanical properties was introduced into EISCHs, and the NIPAAm/CNTs/Fe(phen)3 double network low-voltage-induced shape-changing hydrogel (DN) was synthesized. The experimental results indicated that the DN gained the balance between mechanical properties and deformation ability compared to the NIPAAm-Fe(phen)3 single network and NIPAAm-Fe(phen)3-CNTs nanocomposite single network hydrogels. The DN was found to have the ability to undergo swelling and shrinking as a result of the transition between Fe(phen)3 network iron (Ⅱ) and iron (Ⅲ) states under low-voltage stimulation. The hydrogen bonding and physical entanglement structure between CNTs and polymer chain segments, and physical entanglements between different network, which enable effective energy dissipation. Meanwhile, the special double network structure enabled the hydrogel could decrease the resistance to deformation stress by the slide between two networks.

A residual stress-dependent mixed-mode phase-field model: Application to assessing the role of tailored residual stresses on the mechanical performance of ceramic laminates

Ceramics offer several attractive properties of industrial relevance, e.g. high strength and hardness, low thermal conductivity, and chemical inertness in critical environments. There is thus interest among researchers to improve the fracture toughness of ceramics, which is generally low and considered a major drawback. Numerous experimental studies in the literature report on the enhancement of mechanical performance of ceramic laminates, especially fracture toughness, by tailoring the residual stress, resulting in crack deflection or bifurcation. However, there is a dearth of computational models that can reliably predict the crack path and accurately quantify the improved fracture toughness. In this article, we propose a residual stress-dependent mixed-mode phase-field model within a small deformation set-up. The proposed model is efficient in including any energy dissipation effect in a consistent manner. The model can be exploited as a tool to study the effect of tailored residual stresses on the fracture toughness of ceramic laminates. We have validated our proposal by reproducing the results for a few problems that require the incorporation of residual stresses within the formulation. By conducting a set of four-point bending tests on notched composite beams made of alternating layers of Al2O3 with 5% tetragonal ZrO2 (ATZ) and Al2O3 with 30% monoclinic ZrO2 (AMZ), we demonstrate how tailored residual stresses could indeed influence the mechanical performance of ceramic laminates.

Arrhenius activation energy effect in thermally viscous dissipative flow of micropolar material with gyrotactic microorganisms

The rheology of micropolar material with heat energy transport features is fully progressive, which allows considerable industrial and engineering applications. In this study, numerical analysis is presented to examine the micro-rotation characteristics of magnetized micropolar fluid flow towards the stagnation point region on a porous shrinking surface with gyrotactic microorganisms. To describe the convective energy transport features, Arrehenius activation energy, thermal radiation, Ohmic, and viscous dissipation effects are taken into consideration. The governing equations are converted into ordinary differential equations using appropriate similarity variables. The physical features of flow constraints are displayed and explained for velocity, thermal and solutal distributions, microorganism profile, as well as friction drag, couple stress, and energy transport rate. The results revealed that suction strength contributes to the increment of friction drag, couple stress, and energy transport rate, but the boosted values of the micropolar parameter lower the values of these physical quantities. For a specific range of the shrinking parameter, analysis confirmed the persistence of non-uniqueness solutions. Further, the microorganism profile declines as the bioconvection Lewis number and the bioconvection Peclet number increases. Additionally, according to time-dependent stability analysis, only the upper branch of solutions is physically stable, while the lower branch is not physically.

Towards high strengthening efficiency of equiaxed and platelet-shaped alumina reinforced zirconia ceramics with textured microstructure using DLP-based stereolithography

ZrO2–Al2O3 (ATZ) ceramics are attracting high interest in biomedical applications because of their desirable mechanical performance and biocompatibility. However, strength and toughness are mutually exclusive in structural ceramics. In this paper, based on digital light processing, novel textured ATZ ceramics with obvious crystallographic orientations were fabricated by incorporating Al2O3 platelets with a high aspect ratio and equiaxed particles into the ZrO2 matrix. The optimized fracture toughness of 16.9 ± 0.8 MPa m1/2 was achieved in the textured ATZ ceramic, which was about 67.3 % higher than non-textured ZrO2 ceramics, without sacrificing strength. The coupling toughening effects of macrolayer structure, equiaxed and platelet-shaped Al2O3 particles, and ZrO2 particles were responsible for the enhanced mechanical performance. The macroscale toughening of 3D-printed lamellar architecture led to effective energy dissipation. Additionally, the crack deflection and crack branching induced by dual-morphology Al2O3 particles, accompanied by the phase transformation of the ZrO2 matrix, were significant microscopic toughening mechanisms.

Innovative design and experimental validation of dynamic balance in rotary compressors based on particle damping energy dissipation technology

Dynamic imbalance is one of the primary issues in rotary compressor applications, which can generate significant vibration. A dynamic balance design is required to minimize the moment and additional inertia force, which can be eliminated by adding a counterweight. This paper utilized a solid plate that has cavities filled with particle damper as a novel design to satisfy the dynamic balance. Vibrational energy is dissipated in collisions between particles through momentum exchange and is converted into energy for consumption that consists of inelastic collision energy and frictional energy. The discrete element method (DEM) and multi-body dynamics (MBD) were applied for two-way coupling for a dynamic balance simulation. The impact of particle size, friction coefficient, and restitution coefficient on energy dissipation in rotary compressors was evaluated, and the particle radius of 1 mm produced the most satisfactory. The experiment measured the vibrational acceleration in the tangential and radial directions at a particular duration and frequency to reflect the particle damper’s dynamic balance and energy dissipation effect. Both simulation and experimental results confirmed that the novel design features are more acceptable than the original to satisfy the dynamic balance of a rotary compressor.

Elastic architected mechanical metamaterials with negative stiffness effect for high energy dissipation and low frequency vibration suppression

In this research, mechanical metamaterials with negative stiffness (NS) effect were architected and fabricated for high energy dissipation and low frequency vibration suppression. Periodic cellular metamaterials formed by connecting multiple NS elements in series exhibited hysteresis and lengthy sawtooth loading and unloading plateaus, which made them desirable for use in energy dissipation applications. And the key point was that the deformation of these metamaterials was completely reversible. To determine the underlying cause of hysteresis, the mechanical behavior with phase-transition characteristics was analyzed. Then, a finite element model was built, and the numerical simulation results were compared to the experimental test findings of the metamaterials, and the two were in good agreement, verifying the validity of the model. Furthermore, the influences of structural parameters on mechanical characteristics were systematically investigated and discussed utilizing the numerical models that had undergone experimental validation. The energy dissipation effect resulting from the phase transformation mechanisms could also be applied to the field of vibration control. Corresponding hammer tests were performed to explore the dynamic behavior of the NS metamaterials. The results show that the proposed metamaterials exhibit excellent vibration suppression performance, especially for low frequency vibration mitigation.

Research on the application performance of the corrugated structures in gas wave tubes

This paper proposes a new corrugated gas wave tube to enhance the energy dissipation effect of a static gas wave refrigerator. The tube was based on enhanced heat transfer theory, and its heat transfer efficiency and flow field under different pressure ratios were analyzed. The results demonstrated that the corrugated structure improved heat transfer efficiency compared with smooth tubes. Furthermore, the study investigated the cooling efficiency of gas wave tubes with the application of the corrugated structure under different conditions. The findings indicated that increasing the corrugation percentage led to a fluctuating increase in cooling efficiency. At a pressure ratio of five, the highest cooling efficiency could be improved by 12.65%. By analyzing the motion state of the shock wave in the tube, the gas Nu number, and the law of motion of the wave system, it was determined that the corrugated structure effectively reduced the intensity of the reflected shock wave and enhanced energy dissipation at the end of the tube, increasing cooling efficiency. The experiment was conducted under consistent working conditions, and the efficiency showed varying increases. After thorough research, it could be concluded that using a 60% corrugated gas wave tube proportion yielded the greatest improvement in cooling efficiency.

Seismic Mitigation Effect of Lever-Type Lead Viscoelastic Node Dampers

Energy dissipation damping technology is usually used for infrastructure construction in seismic regions. In this study, a lever-type lead viscoelastic node damper (LTLVND), which can capture small rotational displacements of the infrastructure under seismic excitation, is innovatively proposed based on the leverage effect. The characteristics of energy-absorbing capacity of the LTLVND and its mitigation effect on the dynamics of the structure under seismic excitation are studied. Testing and modelling results show that a satisfactory energy dissipation effect can be observed for the innovative lead viscoelastic damper (LTLVND). Finally, a seismic analysis of a concrete frame structure with LTLVNDs is carried out. Pushover analysis and dynamic elastoplastic analysis are included. It is shown that a significant improvement in structural performance under seismic conditions can be achieved with the addition of LTLVNDs at appropriate locations.

Negative capacitance gate stack and Landau FET-based voltage amplifiers and circuits: Impact of ferroelectric thickness and domain variations

This article analyzes the impact of ferroelectric hafnium zirconium oxide (HZO) thickness (tFE) and domain number (N) variations on the negative capacitance (NC) effect in metal/HZO/metal gate stack and its implications on Landau FET-based device-circuit co-design through simulations. As tFE decreases, the NC effect weakens, resulting in less S-shaped hysteresis loops for charge and polarization versus voltage characteristics. The study highlights the trade-off between energy dissipation and NC effect voltage window in ferroelectric devices and the importance of balancing both. We developed Landau FET-based voltage amplifiers (VA), including passive VA (PVA) and active VA (AVA), and compared to existing counterparts such as P(VDF-TrFE)-PVA and PZT-AVA, across low and high frequencies. The proposed PVA shows a 22.60% and 54.31% increase in amplification (ANC) at low and high frequencies, respectively, compared to P(VDF-TrFE)-PVA. The AVA exhibits a 17.86% increase in ANC at low frequencies compared to PZT-AVA but no ANC at higher frequencies due to symmetry-breaking. The Landau FET-based inverter shows a sharp state transition than the CMOS inverter, but this sharpness depends on tFE, N, and the degree of NC effect. The Landau FET-based fan-out-4 inverter with 7.7 nm tFE and N = 16 is 25.49% faster than the Si MOSFET inverter. Moreover, the impact of tFE and N on the performance of the proposed 5-stage ring oscillator (RO) is investigated concerning state-of-the-art CMOS RO counterparts. The 5-stage RO using Landau FET-based inverters showed (1.26–18.9) times higher oscillation frequency (fOSC) and (17.93–5.71) times reduced power dissipation compared to the existing CMOS ROs. Finally, we examined how process variations impact the fOSC in the proposed 5-stage Landau FET-based RO. The findings indicate a standard deviation of 0.39 GHz in the distribution of fOSC. These findings highlight the interplay between tFE scaling, N variations, and transient NC effect, advancing Landau FET-based devices for future NC electronics.

Assembling feather-like reentrant structures with multiple mechanical properties fabricated by laser powder bed fusion

A new assembly design method for structural components is proposed. Inspired by the feathers of the grey crane, which have an energy dissipation effect, novel re-entrant scapus component and novel re-entrant double-crank component are proposed. Novel re-entrant structures are formed by assembling honeycomb structure (HS), poisson structure (PS), and chiral structure (CS). Laser powder bed fusion technology (LPBF) is utilized for the manufacturing of bio-inspired structures. And the impact of structural assembly on mechanical performance is comprehensively analyzed through experimental, numerical, and theoretical approaches. Euler theory is employed to predict the influence of bionic components on structural load trends, while explaining the relationship between compression load and deformation. Specifically, the average load capacity of bio-inspired scapus re-entrant structures and double-crank re-entrant structures exceeds that of their original designs by at least 55% and 13.2%, respectively. Moreover, specific energy absorption increases by a minimum of 8.6% and 3.4%, accompanied by improved heat dissipation performance in these structures. Finally, battery pack impact resistance models as well as thermal conductivity models for electric-powered vehicles are presented as examples to validate the potential application prospects of this novel bio-inspired re-entrant structure in engineering.

Effect of Viscous Energy Dissipation on Transient Laminar Free Convective Flow of a Dusty Viscous Fluid through a Porous Medium

Effect of Viscous Energy Dissipation on Transient Laminar Free Convective Flow of a Dusty Viscous Fluid through a Porous Medium

Experimental study on rotational impact dampers

Integrating the benefits of rotational nonlinear energy sinks (NESs) and impact NESs while eliminating the negative effects of impacts, rotational impact dampers (RIDs) are proposed in this study. RIDs consist of multiple eccentric masses that rotate in the same horizontal plane about a common pivot, with impacts occurring between adjacent rotators to facilitate fast and effective energy dissipation. First, the development of the RID system is presented. Subsequently, experiments are conducted on a two-story frame structure under impulse excitation to validate the feasibility of RIDs. The impacts of the RIDs with two, three, and four rotators are identified and their control effectiveness is analyzed. The experimental results demonstrate that the RIDs can effectively attenuate the vibration of the structure, with the number of rotators being the main factor affecting the control capacity. With physical validation provided, this short communication highlights the great potential of RIDs as a viable solution for control problems involving different types of uncertainties.

Damage constitutive model of uniaxially compressed coal material considering energy dissipation

Coal plays a dominant role in China's energy production and consumption, which also serves as the cornerstone for energy security. The constitutive relationship of coal material is of great significance for the quantitative characterization and evaluation of mechanical properties of isolated coal pillars. From an energy perspective, coal failure is driven by energy, and the energy-based damage characterization provides a basis for the establishment of constitutive model. In this study, since the constitutive model based on the classical Lemaitre's hypothesis shows a significant error in presenting the nonlinear constitutive relationship of coal material, a correction coefficient considering the compaction effect of coal material is first introduced. Then, a novel damage constitutive model that can accurately describe the overall compression state of coal material is constructed. Finally, the theoretical model is compared with exiting models using the experimental data of five types of coal material from different mines. The results show that the evolution of energy dissipation damage variable is highly consistent with that of stress–strain relations. The established constitutive model considering energy dissipation and compaction effect can more accurately describe the nonlinear strength and deformation characteristics of coal material than the classical and existing models. Notably, this new model can be effectively extended to the single cyclic compression conditions to reproduce the loading-unloading-reloading process of coal material.