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Vibration control of a structure using Magneto-Rheological grease damper

Shinya SUGIYAMA, Tomoki SAKURAI, Shin MORISHITA

《机械工程前沿（英文）》 2013年第8卷第3期页码 261-267 doi: 10.1007/s11465-013-0268-4

摘要：

This paper describes an application study of Magneto-Rheological (MR) grease damper to a structure with three stories. MR fluid is known as one of successful smart materials whose rheological properties can be varied by magnetic field strength, and has been applied to various kinds of device such as dampers, clutches, engine mounts, etc. However, ferromagnetic particles dispersed in MR fluid settle out of the suspension after a certain interval due to the density difference between the particles and their career fluid. To overcome this defect, we have developed a new type of controllable working fluid using grease as the career of magnetic particles. Network of thickener in grease is expected to hold the magnetic particles and prevent them from settled down. No or little sedimentation was observed in MR grease whose characteristics could be controlled by the magnetic field strength. MR grease was introduced into a cylindrical damper and its performance was studied. As a result, it was confirmed that the damping force of MR grease damper could be controlled by the applied electric current to the coil in the cylinder of damper. Furthermore, vibration response of a three-story model structure equipped with MR grease damper was investigated experimentally, and it was shown that MR grease damper worked effectively as a semi-active damper.

关键词： vibration control damper smart material Magneto-Rheological (MR) grease MR fluid

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Analysis and experiment of controllability of magnetorheological fluids based on micro-pipeline

Yongqing SU, Yikuan SONG, Jiguang YUE

《机械工程前沿（英文）》 2009年第4卷第3期页码 339-344 doi: 10.1007/s11465-009-0048-3

摘要： The controllability of the magneto-rheological fluid (MRF) flowing through a micro-pipeline is analyzed. The coupled formulas for MRF are deduced by analyzing the property of the flow field and magnetic field. Then, the relationship between the flow speed of MRF and the special shear stress under the effect of the magnetic field is founded. The model of the MRF and micro-pipeline is established by using multi-physics software of Comsol, the curve of - in an ideal condition is attained by modifying parameters, and by adding the boundary condition of the model. This paper provides a theoretical proof of the controllability of MRF flowing through the micro-pipeline and explores MRF’s application on the micro-drive and control field.

关键词： Magneto-rheological fluids (MRF) micro-pipeline coupled model multi-physics simulation

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Effect of magneto rheological damper on tool vibration during hard turning

P. Sam PAUL, A. S. VARADARAJAN

《机械工程前沿（英文）》 2012年第7卷第4期页码 410-416 doi: 10.1007/s11465-012-0341-4

摘要：

Recently, the concept of hard turning has gained considerable attention in metal cutting as it can apparently replace the traditional process cycle of turning, heat treating, and finish grinding for assembly of hard wear resistant steel parts. The present investigation aims at developing a magneto rheological (MR) fluid damper for suppressing tool vibration and promoting better cutting performance during hard turning. The magneto rheological Fluid acts as a viscoelastic spring with non-linear vibration characteristics that are controlled by the composition of the magneto rheological fluid, the shape of the plunger and the electric parameters of the magnetizing field. Cutting experiments were conducted to arrive at a set of electrical, compositional and shape parameters that can suppress tool vibration and promote better cutting performance during turning of AISI 4340 steel of 46 HRC with minimal fluid application using hard metal insert with sculptured rake face. It was observed that the use of MR fluid damper reduces tool vibration and improves the cutting performance effectively. Also commercialization of this idea holds promise to the metal cutting industry.

关键词： tool vibration magneto rheological damper hard turning surface finish tool wear

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Creep and recovery behaviors of magnetorheological elastomers

Weihua LI, Yang ZHOU, Tongfei TIAN, Gursel ALICI,

《机械工程前沿（英文）》 2010年第5卷第3期页码 341-346 doi: 10.1007/s11465-010-0096-8

摘要： This paper presents experimental and modeling study of creep and recovery behaviors of magneto-rheological elastomers (MREs) under constant stresses. Experimental study was accomplished using a rheometer with parallel-plate geometry. Under constant stresses ranging from a small value to a large one, the resultant strains were recorded. The experimental results demonstrated that MREs behave as linear visocleastic properties. The effects of the magnetic field and stress on MRE creep behaviors were discussed. Moreover, a four-parameter viscoelastic model was developed to describe MRE creep behaviors. The comparison between the experimental results and the modeling predictions indicates that the model can predict MRE creep behaviors very well.

关键词： magneto-rheological elastomers (MREs) creep recovery linear viscoelastic model

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Synthesis of novel magneto-hybrid polyoxometalate composite membrane with simultaneous photocatalytic

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1450-1459 doi: 10.1007/s11705-023-2310-3

摘要： Membrane technology is ideal for removing aqueous humic acid, but humic acid deposits cause membrane fouling, a significant challenge that limits its application. Herein, this work proposed an alternative approach to the controllably magnetically induced magneto-hybrid polyoxometalate (magneto-HPOM) nanocomposite migration toward the polyethersulfone (PES) membrane surface under a magnetic field to enhance the self-cleaning and antifouling functionalities of the membrane. Before incorporating magneto-HPOM nanocomposite into the PES casting solution, functionalized magnetite nanoparticles (F-MNP) were first coated with HPOM photocatalyst to fabricate a magneto-HPOM-PES membrane. It was shown that the apparent impacts of this novel magneto-HPOM-PES membrane on the hydrophilic behavior and photocatalytic properties of the magneto-HPOM nanocomposite improve the hydrophilicity, separation performance, antifouling and self-cleaning properties of the membrane compared with neat PES membrane. Furthermore, after exposure to ultraviolet light, the magneto-HPOM-PES membrane can be recovered after three cycles with a flux recovery ratio of 107.95%, 100.06%, and 95.56%, which is attributed to the temporal super hydrophilicity effect. Meanwhile, the magneto-HPOM-PES membrane could efficiently maintain 100% humic acid rejection for the first and second cycles and 99.81% for the third cycle. This study revealed a novel approach to fabricating membranes with high antifouling and self-cleaning properties for water treatment.

关键词： magneto-hybrid polyoxometalate nanocomposite composite membrane antifouling self-cleaning magnetic and photocatalytic responsiveness

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Seismic performance of steel MRF building with nonlinear viscous dampers

Baiping DONG,James M. RICLES,Richard SAUSE

《结构与土木工程前沿（英文）》 2016年第10卷第3期页码 254-271 doi: 10.1007/s11709-016-0348-8

摘要： This paper presents an experimental study of the seismic response of a 0.6-scale three-story seismic-resistant building structure consisting of a moment resisting frame (MRF) with reduced beam sections (RBS), and a frame with nonlinear viscous dampers and associated bracing (called the DBF). The emphasis is on assessing the seismic performance for the design basis earthquake (DBE) and maximum considered earthquake (MCE). Three MRF designs were studied, with the MRF designed for 100%, 75%, and 60%, respectively, of the required base shear design strength determined according to ASCE 7-10. The DBF with nonlinear viscous dampers was designed to control the lateral drift demands. Earthquake simulations using ensembles of DBE and MCE ground motions were conducted using the real-time hybrid simulation method. The results show the drift demand and damage that occurs in the MRF under seismic loading. Overall, the results show that a high level of seismic performance can be achieved under DBE and MCE ground motions, even for a building structure designed for as little as 60% of the base shear design strength required by ASCE 7-10 for a structure without dampers.

关键词： seismic response steel MRF nonlinear viscous damper design basis earthquake real-time hybrid simulation

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Effect of different high viscosity modifiers on rheological properties of high viscosity asphalt

《结构与土木工程前沿（英文）》 2021年第15卷第6期页码 1390-1399 doi: 10.1007/s11709-021-0775-z

摘要： High viscosity asphalt (HVA) has been a great success as a drainage pavement material. However, the larger porosity of drainage asphalt mixtures weakens the cohesion and adhesion and leads to premature rutting, water damage, spalling and cracking. The purpose of this study was to investigate the rheological properties of HVA prepared using different high viscosity modifiers through conventional tests, Brookfield viscosity tests, dynamic shear rheometer tests and bending beam rheometer tests. The conventional performance results demonstrated SBS + rubber asphalt (SRA-1/2) exhibited excellent elastic recovery and low-temperature flexibility. The 60°C dynamic viscosity results indicated TPS + rubber asphalt (TRA) had the excellent adhesion. The rotational viscosity results and rheological results indicated that SRA-2 not only exhibited excellent temperature stability and workability, as well as excellent resistance to deformation and rutting resistance, but also exhibited excellent low-temperature cracking resistance and relaxation performance. Based on rheological results, the PG classification of HVA was 16% rubber + asphalt for PG76-22, 20% rubber + asphalt for PG88-22, TRA and SRA-1/2 for PG88-28. From comprehensive evaluation of the viscosity, temperature stability and sensitivity, as well as high/low temperature performance of HVA, SRA-2 was found to be more suited to the requirements of drainage asphalt pavement materials.

关键词： high viscosity asphalt rheological properties rubber modifier viscosity

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Polymer nanocomposites for microactuation and magneto-electric transduction

Kaori YUSE, Benoit GUIFFARD, Rabah BELOUADAH, Lionel PETIT, Laurence SEVEYRAT, Daniel GUYOMAR

《机械工程前沿（英文）》 2009年第4卷第3期页码 350-354 doi: 10.1007/s11465-009-0056-3

摘要： In the last decade, electroactive polymers have attracted much attention especially because of their very actuating capabilities. Large strain is experimentally observed, but under quite high electrical field, which can be a severe drawback for actuating applications. First part of the present paper is concerned with the reduction of applied field onto electroactive polymer films to get a given strain level. Polyurethane (PU) films filled with carbon black (CB) nanoparticles exhibit relatively high strain level under a field of only 12.5 kV/mm. The simple easy-to-make method solution cast method was applied. Even though the generated stress level is still quite low, the present work shows high strain level under quite low field appliance by easy manufacturing, lightweight, and flexible polymer film. Besides, another interest of the present paper is in magneto-elasto-electric effect of a polymer film filled with some magnetic nano particles. Films filled with nonpiezoelectric but with magnetite particles has still short history. With the use of magneto materials, a large magnetic DC bias field is generally required, and it causes big problem on application. The films filled with some magnetite nanoparticles (Fe3O4 and Nickel) are fabricated then examined. It is clearly demonstrated that our films do not require any DC bias. Although linear polarization value is relatively small, the first step of the studies on magnetite nano-filled film is presented.

关键词： electroactive polymers carbon filling actuator nanocarbon electromechanical coupling dielectric polymer actuators polymer actuators microactuation magneto-electric effect

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Influence of pressure and density on the rheological properties of rockfills

Erich BAUER, Zhongzhi FU, Sihong LIU

《结构与土木工程前沿（英文）》 2012年第6卷第1期页码 25-34 doi: 10.1007/s11709-012-0143-0

摘要： Long-term deformations of rockfill dams can be related to the type of dam, the pre-compaction achieved during the construction of the dam, the history of loading events, the rheological properties of the rockfill material used, the seepage behavior caused by defects of the sealing, the interactions of the dam building with the foundation, and the hydrothermal phenomena of the stressed rockfill material. The present paper investigates the rheological properties of coarse grained rockfill materials using a hypoplastic constitutive model. Particular attention is paid to wetting deformation under different deviatoric loading states and pre-compactions. To quantify the state of weathering a so-called “solid hardness” is used in the sense of a continuum description. It is shown that an appropriate modeling of wetting deformations requires a unified description of the interaction at least between the state of weathering, the stress state, the density and the rate of deformation. The results obtained from the numerical simulations are compared with available experimental data for a rockfill material used in Xiaolangdi earth dam.

关键词： rockfills solid hardness wetting deformation hypoplasticity creep

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Preparation and rheological behaviors of PA6/SiO2 nanocompiste

WEI Shanshan, LIU Yuejun, LI Xianggang, HUANG Yugang, WANG Xiayu, ZHANG Ping

《化学科学与工程前沿（英文）》 2007年第1卷第4期页码 332-337 doi: 10.1007/s11705-007-0060-2

摘要： The polyamide 6 (PA6)/SiO nanocomposites were prepared by in situ polymerization and the rheological behaviors were investigated. The morphology of resultant materials was characterized by scanning electron microscopy (SEM) and the rheological behaviors were characterized by capillary rheometer. The results showed that the SiO particle size was around 50 nm and the particles dispersed evenly in PA6 matrix. The nanocomposites were pesudoplastic fluids and the apparent viscosities of nanocomposites increased initially and then decreased with the increase in nano-SiO content at the same temperature. The non-Newtonian indexes of nanocomposites were smaller than those of pure PA6. With the increase in nano-SiO content the apparent viscous activation energies of nanocomposites increased initially and then decreased. The rheological behaviors revealed that there were strong interactions between PA6 macromolecule chains and nano-SiO particles.

关键词： polyamide temperature rheological activation pesudoplastic

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Effects of time-varying liquid bridge forces on rheological properties, and resulting extrudability and

《结构与土木工程前沿（英文）》页码 1295-1309 doi: 10.1007/s11709-023-0999-1

摘要： Extrudability and constructability are two important, yet contradictory issues pertaining to the construction of three-dimensional (3D) printing concrete. Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion, but the printed structure is easily collapsible. However, a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable. This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design. First, a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties. Next, a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out. The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable. Furthermore, an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.

关键词： particle-based simulation liquid bridge force rheological property 3D printing mortar extrudability constructability

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Aging properties and aging mechanism of activated waste rubber powder modified asphalt binder based on rheological

《结构与土木工程前沿（英文）》 2023年第17卷第4期页码 625-636 doi: 10.1007/s11709-023-0938-1

摘要： The research and development of high-performance pavement materials has been intensified owing to the demand for long-life pavements. This study is performed to develop a novel pavement material using waste rubber powder, waste lubricating by-product (LBP), and asphalt. Subsequently, the aging properties and aging mechanism of activated waste rubber powder modified asphalt (ARMA) are investigated based on its rheological properties and micro-characterization. The rheological results show that, compared with waste rubber powder modified asphalt (RMA), ARMA offers a higher aging resistance and a longer fatigue life. A comparison and analysis of the rheological aging parameters of ARMA and RMA show that LBP activation diminishes the aging sensitivity of ARMA. The micro-characterization result shows that the aging of ARMA may be caused by the fact that LBP-activated waste rubber powder is more reactive and can form a dense colloidal structure with asphalt. Therefore, the evaporation loss of asphalt light components by heat and the damage to the colloidal structure by oxygen during the aging process are impeded, and the thermal-oxidative aging resistance of ARMA is improved.

关键词： rubber powder modified asphalt aging mechanism rheological characterization

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An autonomous system for thermal convection of viscoelastic fluids in a porous layer using a thermal

Qi WEI, Xiaohui ZHANG

《能源前沿（英文）》 2010年第4卷第4期页码 507-516 doi: 10.1007/s11708-010-0017-x

摘要： Thermal convection of viscoelastic fluids saturating a horizontal porous layer heated from below is analyzed using a thermal nonequilibrium model to take account of the interphase heat transfer between the fluid and the solid. The viscoelastic character of the flow is considered by a modified Darcy’s law. An autonomous system with five differential equations is deduced by applying the truncated Galerkin expansion to the momentum and heat transfer equations. The effects of interphase heat transfer on the thermal convection of viscoelastic fluids in a porous medium are analyzed and discussed. The results show that the weak interphase heat transfer tends to stabilize the steady convection.

关键词： thermal convection porous media viscoelastic fluid thermal nonequilibrium model

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Combined static mixers for high viscous fluids mixing

Zhenhao XI, Weizhen SUN, Ling ZHAO, Zhaoyan LIU

《化学科学与工程前沿（英文）》 2009年第3卷第1期页码 93-96 doi: 10.1007/s11705-009-0112-x

摘要： A new static mixer Cross-over-Disc has been invented to strip off the boundary layer and to make strong radial mixing. The pressure drop of Cross-over-Disc is 12—26 times as large as that of empty pipe with equivalent diameter and length. The mixing performance of Cross-over-Disc with 14 elements has been investigated in the viscosity range of 190—250 Pa?s by decoloration method, and the gray analysis of images shows that mixing inhomogeneity is about 7.5% and 9.4% for the mixing ratio of 5∶1 and 10∶1, respectively. Furthermore, mixing inhomogeneity for a combination of static mixing elements (four from Cross-over-Disc and three pairs from Sulzer-type) can be decreased to 2.1%—3.1% within a reasonable range of pressure drop.

关键词： static mixer Cross-over-Disc pressure drop mixing performance high viscous fluid

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Investigation of effects of Cocamide Diethanolamide chemical on physical and rheological properties of

《结构与土木工程前沿（英文）》 2022年第16卷第1期页码 99-116 doi: 10.1007/s11709-021-0799-4

摘要： In this study, bituminous binder was modified with Cocamide Diethanolamide chemical, a non-ionic surfactant, and the physical and rheological properties of modified binders were investigated. In addition, Cocamide Diethanolamide has been used for the first time to modify bituminous binder, and this situation makes the study distinctive. Bituminous binder was modified more than once with the chemical by changing modification parameters and using certain additive ratios (1%, 3%, and 5%). The effects of different modification parameters and chemical additive on modified samples were investigated with conventional bitumen tests (softening point, penetration, ductility) and Superpave tests (rotational viscometer, rolling thin film oven test, pressure aging vessel, dynamic shear rheometer, bending beam rheometer). In addition, the structural characteristics of the reference binder and modified samples were examined by X-ray diffraction, Fourier Transform Infrared Spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The examinations showed that Cocamide Diethanolamide softens bituminous binder and lowers processing temperatures. In addition, compared to reference binder, rutting resistances of modified bituminous binders decreased with the increase of additive ratio. However, modification with Cocamide Diethanolamide increased the resistance to fatigue cracks and thermal cracks.

关键词： Cocamide Diethanolamide bitumen modification rheology Superpave tests