In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant ...In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant to investigate the effect of magnetic field intensity,magnetic field loading time,and angle on the mechanical properties of the prepared MRE material during the curing process.The obtained results showed that increasing the magnetic field intensity during the curing process can improve the orientation of the chain structure in the elastomer matrix effectively.However,its mechanical properties are the best under the corresponding magnetic field intensity of 321 mT.Besides,by extending the magnetic field loading time in the curing process,the orientation of the chain structure was optimized,at the same time,the mechanical properties were also improved,and the best loading time is about 20–25 min.By changing the loading angle of the magnetic field during the curing process,the mechanical properties of the MRE were improved.When the loading angle of the magnetic field is 90°,the elastomer showed the best compression mechanical properties and excellent compression reversibility.Besides,for the anisotropic MRE material,the performance with magnetic compression is always better than that without magnetic compression.展开更多
Rapid detection of foodborne pathogens is crucial to prevent the outbreaks of foodborne diseases.In this work,we proposed a novel microfluidic biosensor based on magnetorheological elastomer(MRE)and smartphone.First,m...Rapid detection of foodborne pathogens is crucial to prevent the outbreaks of foodborne diseases.In this work,we proposed a novel microfluidic biosensor based on magnetorheological elastomer(MRE)and smartphone.First,micropump and microvalves were constructed by deforming the MRE under magnetic actuation and integrated into the microfluidic biosensor for fluidic control.Then,the micropump was used to deliver immune porous gold@platinum nanocatalysts(Au@PtNCs),bacterial sample,and immunomagnetic nanoparticles(MNPs)into a micromixer,where they were mixed,incubated and magnetically separated to obtain the Au@PtNC-bacteria-MNP complexes.After 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide were injected and catalyzed by the Au@PtNCs,smartphone was used to measure the color of the catalysate for quantitative analysis of target bacteria.Under optimal conditions,this biosensor could detect Salmonella typhimurium quantitatively and automatically in 1 h with a linear detection range of 8.0×10^(1) CFU/mL to 8.0×10^(4) CFU/mL and a detection limit of 62 CFU/mL.The microfluidic biosensor was compact in size,simple to use,and efficient for detection,and might be used for in-field screening of foodborne pathogens to prevent food poisoning.展开更多
Magnetorheological elastomer (MRE) is a type of smart material of which mechanical and electrical properties can be reversibly controlled by the magnetic field. In this study, the influence of the magnetic field on th...Magnetorheological elastomer (MRE) is a type of smart material of which mechanical and electrical properties can be reversibly controlled by the magnetic field. In this study, the influence of the magnetic field on the surface roughness of MRE was studied by the microscopic modeling method, and the influence of controllable characteristics of the MRE surface on its friction properties was analyzed by the macroscopic experimental method. First, on the basis of existing studies, an improved mesoscopic model based on magneto-mechanical coupling analysis was proposed. The initial surface morphology of MRE was characterized by the W–M fractal function, and the change process of the surface microstructures of MRE, induced by the magnetic interaction between particles, was studied. Then, after analyzing the simulation results, it is found that with the increase in the magnetic field and decrease in the modulus of rubber matrix, the surface of MRE changes more significantly, and the best particle volume fraction is within 7.5%–9%. Furthermore, through experimental observation, it is found that the height of the convex peak on the surface of MRE decreases significantly with the action of the magnetic field, resulting in a reduction in the surface roughness. Consistent with the simulation results, a particle volume fraction of 10% corresponds to a maximum change of 14%. Finally, the macroscopic friction experiment results show that the friction coefficients of MREs with different particle volume fractions all decrease with the decrease in surface roughness under the magnetic field. When the particle volume fraction is 10%, the friction coefficient can decrease by 24.7% under a magnetic field of 400 mT, which is consistent with the trend of surface roughness changes. This shows that the change in surface morphology with the effect of the magnetic field is an important factor in the control of MRE friction properties by magnetic field.展开更多
This study aims at investigating the impact of using the Magnetorheological Elastomers(MREs)medium to improve the formability of T-shaped Inconel 718 tubes during the bulging process.Besides,the influence of the punch...This study aims at investigating the impact of using the Magnetorheological Elastomers(MREs)medium to improve the formability of T-shaped Inconel 718 tubes during the bulging process.Besides,the influence of the punch size and the intensity of the magnetic field on the branch height and wall thickness distribution of the T-shaped Inconel 718 tubes are also explored.The results showed that the parts formed by the punch with a length of 5 mm in the pressurization zone have better forming quality.The external magnetic field can promote a high branch,and by increasing the intensity of the magnetic field,the branch height was increased and then decreased.At the same time,the magnetic field reduced the amount of material accumulation between the guiding zone and the bulging zone.Besides,it promotes the material in the guiding zone to enter the bulging zone and improve the bulging ability of the T-shaped tube.展开更多
Magnetorheological elastomer(MRE)has been demonstrated to be effective in structural vibration control because of controllable stiffness and damping properties with the effect of external magnetic fields.To achieve a ...Magnetorheological elastomer(MRE)has been demonstrated to be effective in structural vibration control because of controllable stiffness and damping properties with the effect of external magnetic fields.To achieve a high performance of MRE device-based vibration control,a robust and accurate model is necessary to describe nonlinear dynamics of MRE device.This article aims at realising this target via nonlinear modeling of an innovative MRE device,i.e.MRE vibration isolator.First,the field-dependent properties of MRE isolator were analysed based on experimental data of the isolator in various dynamic tests.Then,a phenomenal model was developed to account for these unique characteristics of MREbased device.Moreover,an improved PSO algorithm was designed to estimate model parameters.Based on identification results,a generalised model was proposed to clarify the field-dependent properties of the isolator due to varied currents,which was then validated by random and earthquake-excited test data.Based on the proposed model,a frequency control strategy was designed for semi-active control of MRE devices-incorporated smart structure for vibration suppression.Finally,using a three-storey frame model and four benchmark earthquakes,a numerical study was conducted to validate the performance of control strategy based on the generalised current-dependent model with satisfactory results.展开更多
This work deals with the active control of the vibrations of mechanical structures incorporating magnetorheological elastomer. The damping coefficient and shear modulus of the elastomer increase when exposed to a magn...This work deals with the active control of the vibrations of mechanical structures incorporating magnetorheological elastomer. The damping coefficient and shear modulus of the elastomer increase when exposed to a magnetic field. Compared with the vibration control where the elastomer is permanently exposed to a magnetic field, the control of this process through time reduces vibrations more effectively. The experimental study for the vibrations of a sandwich beam filled with an elastomer is conducted, followed by a numerical study using the Abaqus code. The vibration damping is found to be dependent on the loading rate of micro-size ferromagnetic particles in the elastomer.展开更多
In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.freq...In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.frequent intensity,basic intensity,and rare intensity.A theoretical formula for the output of the SIIB is established to provide a basis for the determination of the size of the SIIB.MRE and STMP used in SIIB were prepared,of which the changes of shear storage modulus and damping factor with the magnetic field under different strain are analyzed.The mechanical properties of the SIIB under small displacement,medium displacement,and large displacement are tested,respectively,and the hysteretic characteristics of force–displacement are analyzed.The dynamic mechanical model combining the rheological model,phenomenological model,and bilinear restoring force model is established to represent the behavior of the SIIB.The results showed that the theoretical results agree well with the experimental results,and the model can significantly reflect the dynamic characteristics of SIIB.展开更多
基金The funding for the investigation in this paper mainly comes from the following funds.Funded by the National Natural Science Foundation Key Project of China(Grant No.U1937206)the authors are Li,Xu,Guo,the specific grant numbers was RMB 100,000.Funded by the Jiangsu Province Key Research and Development Project(No.BE2019007-2)+2 种基金the authors are Abd,Cheng,the specific grant numbers was RMB 200,000.Funded by the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA201903)the authors are Wu,Yang,Hu,the specific grant numbers was RMB 50,000.Funded by the Basic Scientific Research Operations(Approval No.NT2020015)the authors are Shen,Tao,Guo,the specific grant numbers was RMB 100,000.
文摘In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant to investigate the effect of magnetic field intensity,magnetic field loading time,and angle on the mechanical properties of the prepared MRE material during the curing process.The obtained results showed that increasing the magnetic field intensity during the curing process can improve the orientation of the chain structure in the elastomer matrix effectively.However,its mechanical properties are the best under the corresponding magnetic field intensity of 321 mT.Besides,by extending the magnetic field loading time in the curing process,the orientation of the chain structure was optimized,at the same time,the mechanical properties were also improved,and the best loading time is about 20–25 min.By changing the loading angle of the magnetic field during the curing process,the mechanical properties of the MRE were improved.When the loading angle of the magnetic field is 90°,the elastomer showed the best compression mechanical properties and excellent compression reversibility.Besides,for the anisotropic MRE material,the performance with magnetic compression is always better than that without magnetic compression.
文摘Rapid detection of foodborne pathogens is crucial to prevent the outbreaks of foodborne diseases.In this work,we proposed a novel microfluidic biosensor based on magnetorheological elastomer(MRE)and smartphone.First,micropump and microvalves were constructed by deforming the MRE under magnetic actuation and integrated into the microfluidic biosensor for fluidic control.Then,the micropump was used to deliver immune porous gold@platinum nanocatalysts(Au@PtNCs),bacterial sample,and immunomagnetic nanoparticles(MNPs)into a micromixer,where they were mixed,incubated and magnetically separated to obtain the Au@PtNC-bacteria-MNP complexes.After 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide were injected and catalyzed by the Au@PtNCs,smartphone was used to measure the color of the catalysate for quantitative analysis of target bacteria.Under optimal conditions,this biosensor could detect Salmonella typhimurium quantitatively and automatically in 1 h with a linear detection range of 8.0×10^(1) CFU/mL to 8.0×10^(4) CFU/mL and a detection limit of 62 CFU/mL.The microfluidic biosensor was compact in size,simple to use,and efficient for detection,and might be used for in-field screening of foodborne pathogens to prevent food poisoning.
基金This work was supported by the National Natural Science Foundation of China (No. 11572320)Science and Technology Research Project of Chongqing Municipal Education Commission (No. KJQN201800644)+1 种基金Special Key Project of Technological Innovation and Application Development in Chongqing (cstc2019jscx-fxyd0005)The authors thank professor Xiaojie WANG from Institute of Advanced Manufacturing Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences and associate professor Shiwei CHEN from Chongqing Institute of Science and Technology for the support and fruitful discussions.
文摘Magnetorheological elastomer (MRE) is a type of smart material of which mechanical and electrical properties can be reversibly controlled by the magnetic field. In this study, the influence of the magnetic field on the surface roughness of MRE was studied by the microscopic modeling method, and the influence of controllable characteristics of the MRE surface on its friction properties was analyzed by the macroscopic experimental method. First, on the basis of existing studies, an improved mesoscopic model based on magneto-mechanical coupling analysis was proposed. The initial surface morphology of MRE was characterized by the W–M fractal function, and the change process of the surface microstructures of MRE, induced by the magnetic interaction between particles, was studied. Then, after analyzing the simulation results, it is found that with the increase in the magnetic field and decrease in the modulus of rubber matrix, the surface of MRE changes more significantly, and the best particle volume fraction is within 7.5%–9%. Furthermore, through experimental observation, it is found that the height of the convex peak on the surface of MRE decreases significantly with the action of the magnetic field, resulting in a reduction in the surface roughness. Consistent with the simulation results, a particle volume fraction of 10% corresponds to a maximum change of 14%. Finally, the macroscopic friction experiment results show that the friction coefficients of MREs with different particle volume fractions all decrease with the decrease in surface roughness under the magnetic field. When the particle volume fraction is 10%, the friction coefficient can decrease by 24.7% under a magnetic field of 400 mT, which is consistent with the trend of surface roughness changes. This shows that the change in surface morphology with the effect of the magnetic field is an important factor in the control of MRE friction properties by magnetic field.
基金supported by the Key Program of the National Natural Foundation of China(No.U1937206)Jiangsu Province Key Research and Development Project(No.BE2019007-2)+2 种基金Opening Project of Jiangsu Key Laboratory of Advanced Structural MaterialsApplication Technology(No.ASMA201903)Basic scientific research operating expenses(No.NT2020015).
文摘This study aims at investigating the impact of using the Magnetorheological Elastomers(MREs)medium to improve the formability of T-shaped Inconel 718 tubes during the bulging process.Besides,the influence of the punch size and the intensity of the magnetic field on the branch height and wall thickness distribution of the T-shaped Inconel 718 tubes are also explored.The results showed that the parts formed by the punch with a length of 5 mm in the pressurization zone have better forming quality.The external magnetic field can promote a high branch,and by increasing the intensity of the magnetic field,the branch height was increased and then decreased.At the same time,the magnetic field reduced the amount of material accumulation between the guiding zone and the bulging zone.Besides,it promotes the material in the guiding zone to enter the bulging zone and improve the bulging ability of the T-shaped tube.
基金This work was supported by the Australian Research Council.
文摘Magnetorheological elastomer(MRE)has been demonstrated to be effective in structural vibration control because of controllable stiffness and damping properties with the effect of external magnetic fields.To achieve a high performance of MRE device-based vibration control,a robust and accurate model is necessary to describe nonlinear dynamics of MRE device.This article aims at realising this target via nonlinear modeling of an innovative MRE device,i.e.MRE vibration isolator.First,the field-dependent properties of MRE isolator were analysed based on experimental data of the isolator in various dynamic tests.Then,a phenomenal model was developed to account for these unique characteristics of MREbased device.Moreover,an improved PSO algorithm was designed to estimate model parameters.Based on identification results,a generalised model was proposed to clarify the field-dependent properties of the isolator due to varied currents,which was then validated by random and earthquake-excited test data.Based on the proposed model,a frequency control strategy was designed for semi-active control of MRE devices-incorporated smart structure for vibration suppression.Finally,using a three-storey frame model and four benchmark earthquakes,a numerical study was conducted to validate the performance of control strategy based on the generalised current-dependent model with satisfactory results.
文摘This work deals with the active control of the vibrations of mechanical structures incorporating magnetorheological elastomer. The damping coefficient and shear modulus of the elastomer increase when exposed to a magnetic field. Compared with the vibration control where the elastomer is permanently exposed to a magnetic field, the control of this process through time reduces vibrations more effectively. The experimental study for the vibrations of a sandwich beam filled with an elastomer is conducted, followed by a numerical study using the Abaqus code. The vibration damping is found to be dependent on the loading rate of micro-size ferromagnetic particles in the elastomer.
基金This work was the supported by National Natural Science Foundation of China[Grant No.51508237]the Primary Research and Development Plan of Jiangsu Province[Grant no.BE2017167]All data included in this study are available upon request by contact with the corresponding author.
文摘In this paper,a novel type of isolator,named segmented intelligent isolation bearing(SIIB),is designed and manufactured,which can meet the requirements of seismic fortification under three seismic intensities,i.e.frequent intensity,basic intensity,and rare intensity.A theoretical formula for the output of the SIIB is established to provide a basis for the determination of the size of the SIIB.MRE and STMP used in SIIB were prepared,of which the changes of shear storage modulus and damping factor with the magnetic field under different strain are analyzed.The mechanical properties of the SIIB under small displacement,medium displacement,and large displacement are tested,respectively,and the hysteretic characteristics of force–displacement are analyzed.The dynamic mechanical model combining the rheological model,phenomenological model,and bilinear restoring force model is established to represent the behavior of the SIIB.The results showed that the theoretical results agree well with the experimental results,and the model can significantly reflect the dynamic characteristics of SIIB.