Simulated comminution that the coal impact rigid wall using finite element soft- ware of explicit formulation based on dynamics model of elastic collision (Hamilton varia- tionnal principle),the critical velocity of t...Simulated comminution that the coal impact rigid wall using finite element soft- ware of explicit formulation based on dynamics model of elastic collision (Hamilton varia- tionnal principle),the critical velocity of the coal impacting comminution was about 10 m/s, and validated the release effect of pressure in the coal impacting comminution,and then extend applied field of the finite element software of explicit formulation LS-DYNA analys- ing impact comminution of the elastic-plastic material.The simulation result has great guidance and reference value for understanding the impact comminution mechanics of coal and other material and manufacturing comminution equipment.展开更多
Estimating weak rock mass modulus has historically proven difficult although this mechanical property is an important input to many types of geotechnical analyses. An empirical database of weak rock mass modulus with ...Estimating weak rock mass modulus has historically proven difficult although this mechanical property is an important input to many types of geotechnical analyses. An empirical database of weak rock mass modulus with associated detailed geotechnical parameters was assembled from plate loading tests per- formed at underground mines in Nevada, the Bakhtiary Dam project, and Portugues Dam project. The database was used to assess the accuracy of published single-variate models and to develop a multivari- ate model for predicting in-situ weak rock mass modulus when limited geoteehnical data are available. Only two of the published models were adequate for predicting modulus of weak rock masses over lim- ited ranges of alteration intensities, and none of the models provided good estimates of modulus over a range of geotechnical properties. In light of this shortcoming, a multivariate model was developed from the weak rock mass modulus dataset, and the new model is exponential in form and has the following independent variables： （1） average block size or joint spacing, （2） field estimated rock strength, （3） dis- continuity roughness, and （4） discontinuity infilling hardness. The multivariate model provided better estimates of modulus for both hard-blocky rock masses and intensely-altered rock masses.展开更多
Impermeable bentonite or its mixtures have been proposed as candidate materials to be used in the geotechnical disposal of radioactive nuclear waste. These materials are filled in the space between a canister containi...Impermeable bentonite or its mixtures have been proposed as candidate materials to be used in the geotechnical disposal of radioactive nuclear waste. These materials are filled in the space between a canister containing radioactive nuclear waste and an underground chamber to absorb the radionuclide emitting from the canister and simultaneously retard its migration accompanying the perrneation of underground water to prevent the surrounding environment from po1lution. On the basis of the established elastoplastic strain-hardening mechanical model considering the material’s dilatancy character,the authors carry out the stress-strain analysis of a thick-wa1l cylinder in a plane strain state subJected to a pressure difference between internal and external pressures. The analysis may be expected to be a theoretical basis for developing a coupled shear and permeability test apparatus for conducting a permeability test along a sheared plane in a specimen. The apparatus will be used to study the effects of shear strain on the variation of geotechnical materials’ permeability coefficient in order to evaluate the influence of shear strain caused by nonuniform deformation and/or earthquake on the long-term safety of the disposal system of radioactive nuclear waste. The theoretlcal analysls methods in this paper can be directly spread to the analysis of the deformation and stability of tunnels or roadways driven in soft soils or high moisture-bearing soft rocks.展开更多
In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investig...In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores.展开更多
The smart magneto-rheological visco-elastomer (MRVE) has a promising application to vibration control.Its dynamic characteristics are described by complex moduli which are applicable to linear dynamics.However,experim...The smart magneto-rheological visco-elastomer (MRVE) has a promising application to vibration control.Its dynamic characteristics are described by complex moduli which are applicable to linear dynamics.However,experimental results show remarkable nonlinear relations between force and deformation for certain large deformations,and the nonlinear dynamic modeling needs to be developed.The present study focuses on the nonlinear dynamic characteristics of MRVE.The MRVE was fabricated and specimens were tested to show nonlinear mechanical properties and dynamic behaviors.The nonlinear effect induced by applied magnetic fields was investigated.A phenomenological model for the dynamic behaviors of MRVE was proposed to describe the nonlinear elasticity,linear damping and hysteretic effect,and the corresponding equivalent linear model in the frequency domain was also given for small deformations.The proposed model is applicable to the dynamics and control analysis of composite structures with MRVE.展开更多
For attaining the optimized locomotory performance of swimming fishes,both the passive visco-elastic properties of the fish body and the mechanical behavior of the active muscles should coordinate with the fish body’...For attaining the optimized locomotory performance of swimming fishes,both the passive visco-elastic properties of the fish body and the mechanical behavior of the active muscles should coordinate with the fish body’s undulatory motion pattern.However,it is difficult to directly measure the visco-elastic constitutive relation and the muscular mechanical performance in vivo.In the present paper,a new approach based on the continuous beam model for steady swimming fish is proposed to predict the fish body’s visco-elastic properties and the related muscle mechanical behavior in vivo.Given the lateral travelling-wave-like movement as the input condition,the required muscle force and the energy consumption are functions of the fish body’s visco-elastic parameters,i.e.the Young’s modulus E and the viscosity coefficient in the Kelvin model.After investigating the variations of the propagating speed of the required muscle force with the fish body’s visco-elastic parameters,we analyze the impacts of the visco-elastic properties on the energy efficiencies,including the energy utilization ratios of each element of the kinematic chain in fish swimming and the overall efficiency.Under the constraints of reasonable wave speed of muscle activation and the physiological feasibility,the optimal design of the passive visco-elastic properties can be predicted aiming at maximizing the overall efficiency.The analysis is based on the small-amplitude steady swimming of the carangiform swimmer,with typical Reynolds number varying from 2.5×104to 2.5×105,and the present results show that the non-dimensional Young’s modulus is 112±34,and the non-dimensional viscosity coefficient is 13 approximately.In the present estimated ranges,the overall efficiency of the swimming fish is insensitive to the viscosity,and its magnitude is about 0.11±0.02,in the predicted range given by previous study.展开更多
文摘Simulated comminution that the coal impact rigid wall using finite element soft- ware of explicit formulation based on dynamics model of elastic collision (Hamilton varia- tionnal principle),the critical velocity of the coal impacting comminution was about 10 m/s, and validated the release effect of pressure in the coal impacting comminution,and then extend applied field of the finite element software of explicit formulation LS-DYNA analys- ing impact comminution of the elastic-plastic material.The simulation result has great guidance and reference value for understanding the impact comminution mechanics of coal and other material and manufacturing comminution equipment.
基金funded by the National Institute of Occupational Safety and Health through research contract 200-2011-39965(Principal Investigator Dr.Kallu)University of Nevada,Reno,NV
文摘Estimating weak rock mass modulus has historically proven difficult although this mechanical property is an important input to many types of geotechnical analyses. An empirical database of weak rock mass modulus with associated detailed geotechnical parameters was assembled from plate loading tests per- formed at underground mines in Nevada, the Bakhtiary Dam project, and Portugues Dam project. The database was used to assess the accuracy of published single-variate models and to develop a multivari- ate model for predicting in-situ weak rock mass modulus when limited geoteehnical data are available. Only two of the published models were adequate for predicting modulus of weak rock masses over lim- ited ranges of alteration intensities, and none of the models provided good estimates of modulus over a range of geotechnical properties. In light of this shortcoming, a multivariate model was developed from the weak rock mass modulus dataset, and the new model is exponential in form and has the following independent variables： （1） average block size or joint spacing, （2） field estimated rock strength, （3） dis- continuity roughness, and （4） discontinuity infilling hardness. The multivariate model provided better estimates of modulus for both hard-blocky rock masses and intensely-altered rock masses.
文摘Impermeable bentonite or its mixtures have been proposed as candidate materials to be used in the geotechnical disposal of radioactive nuclear waste. These materials are filled in the space between a canister containing radioactive nuclear waste and an underground chamber to absorb the radionuclide emitting from the canister and simultaneously retard its migration accompanying the perrneation of underground water to prevent the surrounding environment from po1lution. On the basis of the established elastoplastic strain-hardening mechanical model considering the material’s dilatancy character,the authors carry out the stress-strain analysis of a thick-wa1l cylinder in a plane strain state subJected to a pressure difference between internal and external pressures. The analysis may be expected to be a theoretical basis for developing a coupled shear and permeability test apparatus for conducting a permeability test along a sheared plane in a specimen. The apparatus will be used to study the effects of shear strain on the variation of geotechnical materials’ permeability coefficient in order to evaluate the influence of shear strain caused by nonuniform deformation and/or earthquake on the long-term safety of the disposal system of radioactive nuclear waste. The theoretlcal analysls methods in this paper can be directly spread to the analysis of the deformation and stability of tunnels or roadways driven in soft soils or high moisture-bearing soft rocks.
基金the National Science Foundation of China(21161160556)the National Basic Research Program(973program,2013CB834700)the Open Project of State Key Laboratory of Supramolecular Structure and Materials(SKLSSM201302)
文摘In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores.
基金supported by the National Natural Science Foundation of China (Grant No. 11072215)the Fundamental Research Funds for the Central Universitiesthe Hong Kong Polytechnic University through the Development of Niche Areas Programme (Grant No. 1-BB95)
文摘The smart magneto-rheological visco-elastomer (MRVE) has a promising application to vibration control.Its dynamic characteristics are described by complex moduli which are applicable to linear dynamics.However,experimental results show remarkable nonlinear relations between force and deformation for certain large deformations,and the nonlinear dynamic modeling needs to be developed.The present study focuses on the nonlinear dynamic characteristics of MRVE.The MRVE was fabricated and specimens were tested to show nonlinear mechanical properties and dynamic behaviors.The nonlinear effect induced by applied magnetic fields was investigated.A phenomenological model for the dynamic behaviors of MRVE was proposed to describe the nonlinear elasticity,linear damping and hysteretic effect,and the corresponding equivalent linear model in the frequency domain was also given for small deformations.The proposed model is applicable to the dynamics and control analysis of composite structures with MRVE.
基金supported by the National Natural Science Foundation of China(Grants No.10832010)the Innovation Project of the Chinese Academy of Sciences(Grant No.KJCX2-YW-L05)
文摘For attaining the optimized locomotory performance of swimming fishes,both the passive visco-elastic properties of the fish body and the mechanical behavior of the active muscles should coordinate with the fish body’s undulatory motion pattern.However,it is difficult to directly measure the visco-elastic constitutive relation and the muscular mechanical performance in vivo.In the present paper,a new approach based on the continuous beam model for steady swimming fish is proposed to predict the fish body’s visco-elastic properties and the related muscle mechanical behavior in vivo.Given the lateral travelling-wave-like movement as the input condition,the required muscle force and the energy consumption are functions of the fish body’s visco-elastic parameters,i.e.the Young’s modulus E and the viscosity coefficient in the Kelvin model.After investigating the variations of the propagating speed of the required muscle force with the fish body’s visco-elastic parameters,we analyze the impacts of the visco-elastic properties on the energy efficiencies,including the energy utilization ratios of each element of the kinematic chain in fish swimming and the overall efficiency.Under the constraints of reasonable wave speed of muscle activation and the physiological feasibility,the optimal design of the passive visco-elastic properties can be predicted aiming at maximizing the overall efficiency.The analysis is based on the small-amplitude steady swimming of the carangiform swimmer,with typical Reynolds number varying from 2.5×104to 2.5×105,and the present results show that the non-dimensional Young’s modulus is 112±34,and the non-dimensional viscosity coefficient is 13 approximately.In the present estimated ranges,the overall efficiency of the swimming fish is insensitive to the viscosity,and its magnitude is about 0.11±0.02,in the predicted range given by previous study.
