A metal rubber（MR） dry friction damper was designed based on the load supported by the rotor. An experimental apparatus for obtaining hysteresis loops of support under the precession load was designed. The elastic-d...A metal rubber（MR） dry friction damper was designed based on the load supported by the rotor. An experimental apparatus for obtaining hysteresis loops of support under the precession load was designed. The elastic-damping characteristics of the ring-shaped MR damper used as a rotor support under variable loads were presented by studying the hysteresis loops of the damper. The vibration rigidity and the energy dissipation coefficient were calculated from the hysteresis loops, based on the description of the deformation process of the MR element with simple structure in a dimensionless coordinating system. The calculation results showed that the energy dissipation coefficient in the inner of MR element and on the boundary between the damper and the frame of the rotor support were approximately equal. The comparison of the hysteresis loops for a precession load and a one-axial load indicated a large difference when the coefficient of the energy dissipation and the stiffness of the MR damper were concerned.展开更多
The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal ...The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in (available) lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.展开更多
The effect of deformation of porous material on infiltrative performance is investigated. Based on Darcy theory and Boit principle, the Reynolds equation and mathematical expression of deformable metal rubber （MR） m...The effect of deformation of porous material on infiltrative performance is investigated. Based on Darcy theory and Boit principle, the Reynolds equation and mathematical expression of deformable metal rubber （MR） material under laminar flow are obtained according to the change of porosity of metal rubber. It is shown that the throttle of MR material is dependent on its porosity and diameter of metal wires. It will be of great value for the application of MR in throttle field.展开更多
Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observe...Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observed in the mesh encapsulation region.Confocal microscopy analysis shows that such pat hologies complications such as necrosis formation and microcavities were localized in the area near implant fibers with the size compatible with fiber diameter.And the number of such formnations increase with the increase of the size,number and density of microdefects on the implant surface.Results of mumerical sinulations show that it is possible to control implant installation up to the depth to 4mm with a help of bac kscattering probing.The applicability of OCT imaging for mesh implant control was demonstrated.Special two stage OCT image noise reduction algorithm,including empirical mode decomposition,was proposed for contrast increase and better abnormalities visualization by halving the signal-to-noise ratio.Joint usage of backscattered probing and OCT allows to accurately ascertain implant and surrounding tissue conditions,which reduces the risk of relapse probability.展开更多
The dry friction ring-type vibration isolator is considered as an isotropic continuous medium. A method of dry friction hysteresis loop calculation is proposed based on friction force analysis of contact beam. The fri...The dry friction ring-type vibration isolator is considered as an isotropic continuous medium. A method of dry friction hysteresis loop calculation is proposed based on friction force analysis of contact beam. The friction force is modeled as an equivalent distributed moment to use the finite element method （FEM） to calculate the dry friction vibration isolator hysteresis loop, so the damping characteristics can be obtained. A comparison of the hysteresis loop calculation results and the experimental results shows the average relative error is 2.7 %, it proves the calculation method is feasible.展开更多
Insoluble constituents in 3104 alloy for beverage cans manufacturing play an important role in deep ironing process. This paper studies the effect of Fe content in the alloy on volume fraction of the constituents Al6(...Insoluble constituents in 3104 alloy for beverage cans manufacturing play an important role in deep ironing process. This paper studies the effect of Fe content in the alloy on volume fraction of the constituents Al6(Fe, Mn)3 and Al12(Fe, Mn)3Si and its influence on ironing die pickup. It is shown that with Fe content increase, the amount of these constituents rises that helps prevent tool galling. Trials made at a can plant showed less ironing die changeovers at bodymakers. The optimum Fe content for aluminum can production can be considered between 0.47% and 0.53% that corresponds to 2.0% - 2.3% of insoluble constituent volume fraction. Greater amounts than this cause problems with excessive constituent particle formation and earing;smaller amounts result in increased ironing die galling.展开更多
The first resonant(anti-resonant)frequency and sound absorption coefficient of metal rubber(MR) material are theoretically studied with hard backed samples and with air layer.The equations of the first resonant and an...The first resonant(anti-resonant)frequency and sound absorption coefficient of metal rubber(MR) material are theoretically studied with hard backed samples and with air layer.The equations of the first resonant and anti-resonant frequencies of MR are deduced from the undamped propagation characteristics of porous material.The first resonant and anti-resonance sound absorption coefficients are induced according to the theoretical formula for the acoustic characteristic parameters of MR,and the former is modified while the energy consumption at resonance is taken into consideration.The good agreement between the calculation results of these resonant sound absorption parameters and the experimental results verifies the effectiveness of this calculation method for the performance evaluation of MR as a sound absorption material.展开更多
Introduction:Kuala Lumpur is currently experiencing a large-scale urban transformation.This study explores a multi-buffer ring method to investigate the spatial and temporal dynamics of urban growth in the Kuala Lumpu...Introduction:Kuala Lumpur is currently experiencing a large-scale urban transformation.This study explores a multi-buffer ring method to investigate the spatial and temporal dynamics of urban growth in the Kuala Lumpur metropolitan area by using Geographical Information Systems(GIS)and remote sensing imageries from1989 to 2014.Methods:The first Landsat images from 1989,2001,and 2014 were classified with maximum likelihood classification to produce land cover maps and identify four types of land cover:urban/built-up,agriculture,forest,and water.Then,the area coverage for all the land use types at different points in time were measured and combined with distance from the city center.Later on,urbanization densities from the city center to the outside for every 1-km distance from 1 to 50 km are calculated.Results:City density on the distance of 5,8,15,20,and 30 km was very high in the years 1989 and 2014.Temporally,urban expansion shows fast and slow growth stages with high-speed growth shifting to the east side of the city.Conclusions:In general,the population,traffic conditions,industrialization,and policy are the major factors thatinfluenced the urban expansion.展开更多
The sound absorption performance of Metal Rubber material was studied theoretically and experimentally. The acoustic impedance rate and the sound absorption coefficient were derived based on the acoustic parameters of...The sound absorption performance of Metal Rubber material was studied theoretically and experimentally. The acoustic impedance rate and the sound absorption coefficient were derived based on the acoustic parameters of metal rubber material. The relation of structure constant, compressibility modulus and structural parameters was investigated experimentally. The results showed that the specimen of metal rubber with the same mean porosity diameter had the same structure constant. For the same structural parameters, the compressibility modulus of metal rubber material was approximately constant in certain frequency range. The calculated acoustic parameters are in good agreement with the experimental results, demonstrating the effectiveness of theoretical models.展开更多
The acoustic parameters of metal rubber materials were theoretically and experimentally investigated. Under the assumption that metal rubber materials were homogenous, isotropic and porous structures, formulas were de...The acoustic parameters of metal rubber materials were theoretically and experimentally investigated. Under the assumption that metal rubber materials were homogenous, isotropic and porous structures, formulas were deduced for the calculations of effective sound velocity, characteristic impedance, propagation constant, structural constant and flow resistivity. The structural constant of metal rubber materials with different structural parameters were obtained and analyzed by using experiments. The experimental and theoretical values of characteristic impedance and propagation constant were compared and analyzed. It is shown that the proposed theoretic method based on the homogenous, isotropic and porous material model is suitable to calculate the acoustic parameters of metal rubber materials.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50675042).
文摘A metal rubber（MR） dry friction damper was designed based on the load supported by the rotor. An experimental apparatus for obtaining hysteresis loops of support under the precession load was designed. The elastic-damping characteristics of the ring-shaped MR damper used as a rotor support under variable loads were presented by studying the hysteresis loops of the damper. The vibration rigidity and the energy dissipation coefficient were calculated from the hysteresis loops, based on the description of the deformation process of the MR element with simple structure in a dimensionless coordinating system. The calculation results showed that the energy dissipation coefficient in the inner of MR element and on the boundary between the damper and the frame of the rotor support were approximately equal. The comparison of the hysteresis loops for a precession load and a one-axial load indicated a large difference when the coefficient of the energy dissipation and the stiffness of the MR damper were concerned.
基金Project(50075017) supported by the National Natural Sceince Foundation of China
文摘The lifetime of metal rubber isolator and its characteristics during lifetime experiment were studied. The stepped-up test principle was adopted to study the lifetime of resonant frequency, the breakage form of metal rubber isolator was obtained, and the relation between the energy dissipation, resonant frequency and stiffness was obtained in (available) lifetime of the isolator. Furthermore, the reason for the changes of properties of metal rubber isolator was analyzed with contact model of metal rubber material. The results show that if the resonant amplitude is large, the stiffness of metal rubber isolator will be kept steadily for a long time, its resonant frequency will be stable and the effective working time in the protecting area will be long. The lifetime of metal rubber isolator is more than 1376 h in the experiment. The main failure forms of metal rubber isolator are accumulative wear and breaking of metal wires and spirals. In protecting area the metal rubber isolator can work effectively for a long time, and the effective working time depends on the concrete working condition.
基金This project is supported by National Natural Science Foundation of China (No.50075017)Municipal Youth Foundation of Harbin, China(No.2003AFQXJ035).
文摘The effect of deformation of porous material on infiltrative performance is investigated. Based on Darcy theory and Boit principle, the Reynolds equation and mathematical expression of deformable metal rubber （MR） material under laminar flow are obtained according to the change of porosity of metal rubber. It is shown that the throttle of MR material is dependent on its porosity and diameter of metal wires. It will be of great value for the application of MR in throttle field.
基金supported by the Federal Target Program“Scientific and scientific-pedagogic staff of innovative Russia in 2007-2013”.
文摘Complex investigation of mesh implants was per formed involving laser confocal microscopy,backscattered probing and OCT imaging methods.The growth of endomysium and fat tissue with microcirculation vessels was observed in the mesh encapsulation region.Confocal microscopy analysis shows that such pat hologies complications such as necrosis formation and microcavities were localized in the area near implant fibers with the size compatible with fiber diameter.And the number of such formnations increase with the increase of the size,number and density of microdefects on the implant surface.Results of mumerical sinulations show that it is possible to control implant installation up to the depth to 4mm with a help of bac kscattering probing.The applicability of OCT imaging for mesh implant control was demonstrated.Special two stage OCT image noise reduction algorithm,including empirical mode decomposition,was proposed for contrast increase and better abnormalities visualization by halving the signal-to-noise ratio.Joint usage of backscattered probing and OCT allows to accurately ascertain implant and surrounding tissue conditions,which reduces the risk of relapse probability.
基金the National Natural Science Foundation of China(50275030)the"111" Project (B07018)
文摘The dry friction ring-type vibration isolator is considered as an isotropic continuous medium. A method of dry friction hysteresis loop calculation is proposed based on friction force analysis of contact beam. The friction force is modeled as an equivalent distributed moment to use the finite element method （FEM） to calculate the dry friction vibration isolator hysteresis loop, so the damping characteristics can be obtained. A comparison of the hysteresis loop calculation results and the experimental results shows the average relative error is 2.7 %, it proves the calculation method is feasible.
文摘Insoluble constituents in 3104 alloy for beverage cans manufacturing play an important role in deep ironing process. This paper studies the effect of Fe content in the alloy on volume fraction of the constituents Al6(Fe, Mn)3 and Al12(Fe, Mn)3Si and its influence on ironing die pickup. It is shown that with Fe content increase, the amount of these constituents rises that helps prevent tool galling. Trials made at a can plant showed less ironing die changeovers at bodymakers. The optimum Fe content for aluminum can production can be considered between 0.47% and 0.53% that corresponds to 2.0% - 2.3% of insoluble constituent volume fraction. Greater amounts than this cause problems with excessive constituent particle formation and earing;smaller amounts result in increased ironing die galling.
基金Supported by the National Natural Science Foundation of China(Grant No.50675042)
文摘The first resonant(anti-resonant)frequency and sound absorption coefficient of metal rubber(MR) material are theoretically studied with hard backed samples and with air layer.The equations of the first resonant and anti-resonant frequencies of MR are deduced from the undamped propagation characteristics of porous material.The first resonant and anti-resonance sound absorption coefficients are induced according to the theoretical formula for the acoustic characteristic parameters of MR,and the former is modified while the energy consumption at resonance is taken into consideration.The good agreement between the calculation results of these resonant sound absorption parameters and the experimental results verifies the effectiveness of this calculation method for the performance evaluation of MR as a sound absorption material.
文摘Introduction:Kuala Lumpur is currently experiencing a large-scale urban transformation.This study explores a multi-buffer ring method to investigate the spatial and temporal dynamics of urban growth in the Kuala Lumpur metropolitan area by using Geographical Information Systems(GIS)and remote sensing imageries from1989 to 2014.Methods:The first Landsat images from 1989,2001,and 2014 were classified with maximum likelihood classification to produce land cover maps and identify four types of land cover:urban/built-up,agriculture,forest,and water.Then,the area coverage for all the land use types at different points in time were measured and combined with distance from the city center.Later on,urbanization densities from the city center to the outside for every 1-km distance from 1 to 50 km are calculated.Results:City density on the distance of 5,8,15,20,and 30 km was very high in the years 1989 and 2014.Temporally,urban expansion shows fast and slow growth stages with high-speed growth shifting to the east side of the city.Conclusions:In general,the population,traffic conditions,industrialization,and policy are the major factors thatinfluenced the urban expansion.
基金supported by the National Natural Science Foundation of China(50675042)
文摘The sound absorption performance of Metal Rubber material was studied theoretically and experimentally. The acoustic impedance rate and the sound absorption coefficient were derived based on the acoustic parameters of metal rubber material. The relation of structure constant, compressibility modulus and structural parameters was investigated experimentally. The results showed that the specimen of metal rubber with the same mean porosity diameter had the same structure constant. For the same structural parameters, the compressibility modulus of metal rubber material was approximately constant in certain frequency range. The calculated acoustic parameters are in good agreement with the experimental results, demonstrating the effectiveness of theoretical models.
基金the National Natural Science Foundation of China (50675042)the 111 Project
文摘The acoustic parameters of metal rubber materials were theoretically and experimentally investigated. Under the assumption that metal rubber materials were homogenous, isotropic and porous structures, formulas were deduced for the calculations of effective sound velocity, characteristic impedance, propagation constant, structural constant and flow resistivity. The structural constant of metal rubber materials with different structural parameters were obtained and analyzed by using experiments. The experimental and theoretical values of characteristic impedance and propagation constant were compared and analyzed. It is shown that the proposed theoretic method based on the homogenous, isotropic and porous material model is suitable to calculate the acoustic parameters of metal rubber materials.
