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Analysis of mesoscopic mechanical dynamic characteristics of ballast bed with under sleeper pads
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作者 Xiong Yang Liuyang Yu +3 位作者 Xuejun Wang Zhigang Xu Yu Deng Houxu Li 《Railway Engineering Science》 EI 2024年第1期107-123,共17页
The meso-dynamical behaviour of a high-speed rail ballast bed with under sleeper pads(USPs)was studied.The geometrically irregular refined discrete element model of the ballast particles was constructed using 3D scann... The meso-dynamical behaviour of a high-speed rail ballast bed with under sleeper pads(USPs)was studied.The geometrically irregular refined discrete element model of the ballast particles was constructed using 3D scanning techniques,and the 3D dynamic model of the rail-sleeper-ballast bed was constructed using the coupled discrete element method-multiflexible-body dynamics(DEM-MFBD)approach.We analyse the meso-mechanical dynamics of the ballast bed with USPs under dynamic load on a train and verify the correctness of the model in laboratory tests.It is shown that the deformation of the USPs increases the contact area between the sleeper and the ballast particles,and subsequently the number of contacts between them.As the depth of the granular ballast bed increases,the contact area becomes larger,and the contact force between the ballast particles gradually decreases.Under the action of the elastic USPs,the contact forces between ballast particles are reduced and the overall vibration level of the ballast bed can be reduced.The settlement of the granular ballast bed occurs mainly at the shallow position of the sleeper bottom,and the installation of the elastic USPs can be effective in reducing the stress on the ballast particles and the settlement of the ballast bed. 展开更多
关键词 Under sleeper pads Ballast bed Discrete element method Mesoscopic mechanical dynamic characteristics
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Dynamic Event-Triggered Consensus Control for Input Constrained Multi-Agent Systems With a Designable Minimum Inter-Event Time
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作者 Meilin Li Yue Long +2 位作者 Tieshan Li Hongjing Liang C.L.Philip Chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期649-660,共12页
This paper investigates the consensus control of multi-agent systems(MASs) with constrained input using the dynamic event-triggered mechanism(ETM).Consider the MASs with small-scale networks where a centralized dynami... This paper investigates the consensus control of multi-agent systems(MASs) with constrained input using the dynamic event-triggered mechanism(ETM).Consider the MASs with small-scale networks where a centralized dynamic ETM with global information of the MASs is first designed.Then,a distributed dynamic ETM which only uses local information is developed for the MASs with large-scale networks.It is shown that the semi-global consensus of the MASs can be achieved by the designed bounded control protocol where the Zeno phenomenon is eliminated by a designable minimum inter-event time.In addition,it is easier to find a trade-off between the convergence rate and the minimum inter-event time by an adjustable parameter.Furthermore,the results are extended to regional consensus of the MASs with the bounded control protocol.Numerical simulations show the effectiveness of the proposed approach. 展开更多
关键词 Constrained input designable minimum inter-event time directed communication topology dynamic event-triggered mechanism MASs consensus control
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Experimental and numerical study on dynamic mechanical behaviors of shale under true triaxial compression at high strain rate
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作者 Xiaoping Zhou Linyuan Han +1 位作者 Jing Bi Yundong Shou 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第2期149-165,共17页
High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic ... High-energy gas fracturing of shale is a novel,high efficacy and eco-friendly mining technique,which is a typical dynamic perturbing behavior.To effectively extract shale gas,it is important to understand the dynamic mechanical properties of shale.Dynamic experiments on shale subjected to true triaxial compression at different strain rates are first conducted in this research.The dynamic stress-strain curves,peak strain,peak stress and failure modes of shale are investigated.The results of the study indicate that the intermediate principal stress and the minor principal stress have the significant influence on the dynamic mechanical behaviors,although this effect decreases as the strain rate increases.The characteristics of compression-shear failure primarily occur in shale subjected to triaxial compression at high strain rates,which distinguishes it from the fragmentation characteristics observed in shale under dynamic uniaxial compression.Additionally,a numerical three-dimensional Split Hopkinson Pressure Bar(3D-SHPB),which is established by coupling PFC3D and FLAC3D methods,is validated to replicate the laboratory characteristics of shale.The dynamic mechanical characteristics of shale subjected to different confining stresses are systematically investigated by the coupling PFC3D and FLAC3D method.The numerical results are in good agreement with the experimental data. 展开更多
关键词 Dynamic behaviors True triaxial compression High strain rates Dynamic failure mechanism PFC3D-FLAC3D coupled method
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MODELLING OF MECHANICAL MECHANISM OF CHROMATOGRAPHIC SYSTEM AND THEORETICAL EQUATIONS SHOWING DYNAMICAL CHARACTERISTICS OF CHROMATOGRAPHY
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作者 Wei Qun DENG, Jin Fa YANG Fujian Geological Analysis and Testing Research Center,Fuzhou,350002 Yun DENG Department of Chemical Engineering, University of Waterloo, Canada N2L 3GI 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第7期547-550,共4页
A simple model of chromatographic mechanical mechanism is present, and then a scrics of theoretical chromatographic equations and fundamental Formulae are derived. These theoretical equations and formulae not only res... A simple model of chromatographic mechanical mechanism is present, and then a scrics of theoretical chromatographic equations and fundamental Formulae are derived. These theoretical equations and formulae not only reserve thermodynamic characteristics in the current fundamental chromatographic formulae, but also introduce one or more kinetic parameter, so it is possible to make the macroscopic-control on the effect of kinetic characteristics on chromatographic system. 展开更多
关键词 MODELLING OF mechanical MECHANISM OF CHROMATOGRAPHIC system AND THEORETICAL EQUATIONS SHOWING dynamical CHARACTERISTICS OF CHROMATOGRAPHY 月山
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DynamicMechanical and Chemorheology Analysis for the Blended Epoxy System with Polyurethane Modified Resin 被引量:2
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作者 Xue Xin Yu Rong +6 位作者 Linping Su Zhengmei Qiu Chenjun Yang Ming Liang Ping Ji Guoqiang Zhong Zhanyong Yao 《Journal of Renewable Materials》 SCIE EI 2022年第4期1081-1095,共15页
As the important matrix material,epoxy resin has been widely used in the composites for various fields.On account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable ... As the important matrix material,epoxy resin has been widely used in the composites for various fields.On account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable interests have been conducted to modify the epoxy resin to meet the engineering requirements.In this study,the bio-based polyurethane(PU)modified resin was adopted to modify the pure bisphenol-A epoxy by blending method with various proportions.Aiming to illuminate the curing behavior,mechanical and thermal properties,the blended epoxy systems were characterized by viscosity-time analysis,dynamic mechanical analysis(DMA)at different frequencies and temperatures,mechanical tensile test,thermogravimetric analysis(TGA)and Fourier transform infrared(FT-IR)spectroscopy.The results indicated that the introduction of PU modified epoxy was found to significantly inhibit the viscosity growth rates especially when the content of PU modified epoxy resin is higher than 60%.Notwithstanding the dynamic modulus and T_(g)reduced with the increment of PU modified epoxy,remarkable increment on the elongation at break was found and the flexibility was greatly promoted with the introduction of PU modified epoxy.The proportion of PU modified epoxy in the blends should be put balance considerations to obtain optimal mechanical properties.TGA results and FTIR spectrum demonstrated that the addition of PU modified epoxy did not change the thermal decomposition mechanism and chemical reaction mechanism,but the addition of PU modified epoxy inhibits the curing reaction of epoxy resin by measured and calculated the damping temperature domainT from 35.7℃ to 48.9℃. 展开更多
关键词 Dynamic mechanical property chemorheology analysis blended epoxy system polyurethane modified resin
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Dynamic compressive response of porcine muscle measured using a split Hopkinson bar system with a pair of PVDF force transducers 被引量:1
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作者 Yao-ke Wen Liang Xu +2 位作者 Ai-jun Chen Fang-dong Dong Bin Qin 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第10期298-305,共8页
The classic metallic Split Hopkinson Pressure Bar(SHPB)cannot capture the transmitted signal accurately when measuring soft biological tissue,because of the very low wave impedance and strength of this material.So the... The classic metallic Split Hopkinson Pressure Bar(SHPB)cannot capture the transmitted signal accurately when measuring soft biological tissue,because of the very low wave impedance and strength of this material.So the dynamic compressive response of porcine muscle has been investigated by using a modified SHPB.The forces on both ends of the sample measured using Polyvinylidene fluor(PVDF)transducers were applied to calculate the stress in the specimen instead of the strain gauge signal on the transmitted bar.Moreover,a circular cardboard disk pulse shaper was applied for generating a suitable incident pulse to achieve stress equilibrium and constant strain rates in the specimens.Then,the dynamic mechanical properties of porcine muscle parallel and perpendicular to the fiber directions were measured,and the stress equilibrium process during loading was analyzed,as well as the inertia-induced extra stress being corrected.Furthermore,quasi-static tests were conducted at two different strain rates to investigate the strain rate dependence using a universal material testing machine.The results show that the stress-strain curves are sensitive to strain rate in the two different loading directions.The compressive stress perpendicular to the fiber direction is stiffer than that parallel to the fiber direction.In addition,a strain rate-dependent constitutive model was developed based on the mechanical response of the muscle at different strain rates and fitted to the experimental data.The results show that the overall fit is good,and the constitutive model could describe the muscle's dynamic mechanical properties. 展开更多
关键词 PVDF Hopkinson bar Porcine muscle Dynamic mechanical properties Constitutive model
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Experimental study of the dynamic mechanical responses and failure characteristics of coal under true triaxial confinements 被引量:1
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作者 Zhanguo Ma Pengfei Yan +3 位作者 Shixing Cheng Peng Gong Fuzhou Qi Jianguo Wang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第6期761-772,共12页
Investigations on the dynamic mechanical properties and failure mechanisms of coal under in-situ stress is essential for the prevention of dynamic disasters in deep coal mines.Thus,a modified true triaxial Hopkinson b... Investigations on the dynamic mechanical properties and failure mechanisms of coal under in-situ stress is essential for the prevention of dynamic disasters in deep coal mines.Thus,a modified true triaxial Hopkinson bar was employed to explore the dynamic mechanical behaviors of coal at different confining pressures(0–20 MPa)and strain rates(40–220 s^(-1)).The results show that the dynamic peak stress is positively correlated with lateral static pre-stressσy andσz,but negatively correlated with axial static prestressσx.At approximate strain rates,increasing the lateral static pre-stress facilitates increasing the dynamic peak stress,but the minimum lateral static pre-stress is the primary factor limiting a significant increase in dynamic peak stress of coal.Furthermore,the dynamic differential stress is linearly related to the logarithm of strain rate,and the peak strain varies linearly with strain rate.However,there is no significant correlation between confining pressure and peak strain.Moreover,X-ray CT images and photographic fracture observations of coal samples show the failure patterns under uniaxial and triaxial conditions are splitting failure and shear failure,respectively.The device provides a viable approach for fully comprehending the dynamic mechanical behaviors of rock-like material in complex stress conditions. 展开更多
关键词 COAL True triaxial SHPB test Dynamic mechanical properties Failure characteristics
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Dynamic mechanical characteristics of frozen subgrade soil subjected to freeze-thaw cycles 被引量:1
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作者 WANG Dan LIU En-long +3 位作者 YANG Cheng-song LIU You-qian ZHU Sheng-xian YU Qi-hao 《Journal of Mountain Science》 SCIE CSCD 2023年第1期242-255,共14页
As a widely-applied engineering material in cold regions, the frozen subgrade soils are usually subjected to seismic loading, which are also dramatically influenced by the freeze-thaw(F-T)cycles due to the varying tem... As a widely-applied engineering material in cold regions, the frozen subgrade soils are usually subjected to seismic loading, which are also dramatically influenced by the freeze-thaw(F-T)cycles due to the varying temperature. A series of dynamic cyclic triaxial experiments were conducted through a cryogenic triaxial apparatus for exploring the influences of F-T cycles on the dynamic mechanical properties of frozen subgrade clay.According to the experimental results of frozen clay at the temperature of-10℃, the dynamic responses and microstructure variation at different times of F-T cycles(0, 1, 5, and 20 cycles) were explored in detail.It is experimentally demonstrated that the dynamic stress-strain curves and dynamic volumetric strain curves of frozen clay are significantly sparse after 20F-T cycles. Meanwhile, the cyclic number at failure(Nf) of the frozen specimen reduces by 89% after 20freeze-thaw cycles at a low ratio of the dynamic stress amplitude. In addition, with the increasing F-T cycles,the axial accumulative strain, residual deformation,and the value of damage variable of frozen clay increase, while the dynamic resilient modulus and dynamic strength decrease. Finally, the influence of the F-T cycles on the failure mechanisms of frozen clay was discussed in terms of the microstructure variation. These studies contribute to a better understanding of the fundamental changes in the dynamic mechanical of frozen soils exposed to F-T cycles in cold and seismic regions. 展开更多
关键词 Freeze-thaw cycles Frozen clay Dynamic triaxial test Dynamic mechanical properties
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Dynamic mechanical characteristics of NdFeB in electromagnetic brake 被引量:1
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作者 Lei Li Guo-lai Yang Li-qun Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第1期111-125,共15页
With the continuous development of artillery,the disadvantages of hydraulic recoil brakes gradually appear.At the same time,the appearance of high-performance Nd Fe B permanent magnet makes it possible to apply electr... With the continuous development of artillery,the disadvantages of hydraulic recoil brakes gradually appear.At the same time,the appearance of high-performance Nd Fe B permanent magnet makes it possible to apply electromagnetic braking technology to recoil mechanism.In this paper,prototype tests of a certain artillery were carried out to verify the feasibility of the electromagnetic brake(EMB)and obtain the electromagnetic braking force.Due to the brittleness of Nd Fe B,in order to eliminate the worry about the safety of EMB,SHPB experiments of Nd Fe B were carried out.Then,based on the assumption of uniform crack distribution,the law of crack propagation and damage accumulation was described theoretically,and the damage constitutive model suitable for brittle materials was proposed by combining the Zhu-Wang-Tang(ZWT)equation.Finally,the numerical simulation model of the artillery prototype was established and through calculation,the dynamic mechanical characteristics of Nd Fe B in the prototype were analyzed.The calculation results show that the strength of Nd Fe B can meet the requirements of the use in the working process.From the perspective of damage factor,the damage value of the permanent magnet on the far right is larger,and the damage value of the inner ring gradually decreases to the outer ring. 展开更多
关键词 Electromagnetic brake Sintered NdFeB Damage constitutive Dynamic mechanical characteristics
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Rheological Simulating Study of Mechanical Conditions for Syn-extensional Basin and Mountain Coupling System
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作者 Wu Hongling Yin Xiulan Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081 《Journal of China University of Geosciences》 SCIE CSCD 2003年第4期330-338,共9页
This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical s... This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical simulating method. A geological dynamic extensional mode given by some geologists is theoretically discussed and verified. The study shows that lithosphere thickening or thinning is closely related to the thermal activity, or in other words, thermal convection beneath the lithosphere. It is one of the important factors affecting the formation of the basin-mountain coupling system. As an essential condition, only the upward buoyant force and the horizontal dragging force caused by the thermal convection jointly act on the bottom of the lithosphere, the stress and strain states in rock's layers are advantageous to forming the tectonic-landforms of the basin-mountain coupling system. A study on the creep features of the lithosphere shows that the stress and strain in the rock's layers vary with time when the lasting forces act on the boundary. They increase rapidly at initial stage and decrease steadily after reaching the peak value. Phenomena of stress relaxation are significant for studying the tectonic evolution. 展开更多
关键词 lithosphere thinning basin-mountain system dynamic mechanism CREEP numerical simulating method.
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Integral Invariants of a Holonomic Dynamical System
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作者 Naseer Ahmed (Mathematics Department . Quaid-i-Azam University, Islamabad, Pakistan) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第8期755-765,共11页
This paper uses Poincare’s formalism to study . the integral invariants of aconservative holonomic dynamical system Introducing new parameters for theasynchronous variation, a generalization of the poincare and ... This paper uses Poincare’s formalism to study . the integral invariants of aconservative holonomic dynamical system Introducing new parameters for theasynchronous variation, a generalization of the poincare and Poincare-Cartan integralinvariants is presented. 展开更多
关键词 analysis mechanics. holonomic dynamical system integralinvariants SYNCHRONOUS ASYNCHRONOUS
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Distributed dynamic event-based finite-time dissipative synchronization control for semi-Markov switched fuzzy cyber-physical systems against random packet losses
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作者 伍锡如 张煜翀 +1 位作者 张畑畑 张斌磊 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期328-342,共15页
This paper is concerned with the finite-time dissipative synchronization control problem of semi-Markov switched cyber-physical systems in the presence of packet losses, which is constructed by the Takagi–Sugeno fuzz... This paper is concerned with the finite-time dissipative synchronization control problem of semi-Markov switched cyber-physical systems in the presence of packet losses, which is constructed by the Takagi–Sugeno fuzzy model. To save the network communication burden, a distributed dynamic event-triggered mechanism is developed to restrain the information update. Besides, random packet dropouts following the Bernoulli distribution are assumed to occur in sensor to controller channels, where the triggered control input is analyzed via an equivalent method containing a new stochastic variable. By establishing the mode-dependent Lyapunov–Krasovskii functional with augmented terms, the finite-time boundness of the error system limited to strict dissipativity is studied. As a result of the help of an extended reciprocally convex matrix inequality technique, less conservative criteria in terms of linear matrix inequalities are deduced to calculate the desired control gains. Finally, two examples in regard to practical systems are provided to display the effectiveness of the proposed theory. 展开更多
关键词 cyber-physical systems finite-time synchronization distributed dynamic event-triggered mechanism random packet losses
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Set-Membership Filtering Approach to Dynamic Event-Triggered Fault Estimation for a Class of Nonlinear Time-Varying Complex Networks
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作者 Xiaoting Du Lei Zou Maiying Zhong 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期638-648,共11页
The present study addresses the problem of fault estimation for a specific class of nonlinear time-varying complex networks,utilizing an unknown-input-observer approach within the framework of dynamic event-triggered ... The present study addresses the problem of fault estimation for a specific class of nonlinear time-varying complex networks,utilizing an unknown-input-observer approach within the framework of dynamic event-triggered mechanism(DETM).In order to optimize communication resource utilization,the DETM is employed to determine whether the current measurement data should be transmitted to the estimator or not.To guarantee a satisfactory estimation performance for the fault signal,an unknown-input-observer-based estimator is constructed to decouple the estimation error dynamics from the influence of fault signals.The aim of this paper is to find the suitable estimator parameters under the effects of DETM such that both the state estimates and fault estimates are confined within two sets of closed ellipsoid domains.The techniques of recursive matrix inequality are applied to derive sufficient conditions for the existence of the desired estimator,ensuring that the specified performance requirements are met under certain conditions.Then,the estimator gains are derived by minimizing the ellipsoid domain in the sense of trace and a recursive estimator parameter design algorithm is then provided.Finally,a numerical example is conducted to demonstrate the effectiveness of the designed estimator. 展开更多
关键词 Dynamic event-triggered mechanism(DETM) fault estimation nonlinear time-varying complex networks set-member-ship filtering unknown input observer
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Hybrid Dynamic Variables-Dependent Event-Triggered Fuzzy Model Predictive Control
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作者 Xiongbo Wan Chaoling Zhang +2 位作者 Fan Wei Chuan-Ke Zhang Min Wu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第3期723-733,共11页
This article focuses on dynamic event-triggered mechanism(DETM)-based model predictive control(MPC) for T-S fuzzy systems.A hybrid dynamic variables-dependent DETM is carefully devised,which includes a multiplicative ... This article focuses on dynamic event-triggered mechanism(DETM)-based model predictive control(MPC) for T-S fuzzy systems.A hybrid dynamic variables-dependent DETM is carefully devised,which includes a multiplicative dynamic variable and an additive dynamic variable.The addressed DETM-based fuzzy MPC issue is described as a “min-max” optimization problem(OP).To facilitate the co-design of the MPC controller and the weighting matrix of the DETM,an auxiliary OP is proposed based on a new Lyapunov function and a new robust positive invariant(RPI) set that contain the membership functions and the hybrid dynamic variables.A dynamic event-triggered fuzzy MPC algorithm is developed accordingly,whose recursive feasibility is analysed by employing the RPI set.With the designed controller,the involved fuzzy system is ensured to be asymptotically stable.Two examples show that the new DETM and DETM-based MPC algorithm have the advantages of reducing resource consumption while yielding the anticipated performance. 展开更多
关键词 Dynamic event-triggered mechanism(DETM) hybrid dynamic variables model predictive control(MPC) robust positive invariant(RPI)set T-S fuzzy systems
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Flexible Load Participation in Peaking Shaving and Valley Filling Based on Dynamic Price Incentives
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作者 Lifeng Wang Jing Yu Wenlu Ji 《Energy Engineering》 EI 2024年第2期523-540,共18页
Considering the widening of the peak-valley difference in the power grid and the difficulty of the existing fixed time-of-use electricity price mechanism in meeting the energy demand of heterogeneous users at various ... Considering the widening of the peak-valley difference in the power grid and the difficulty of the existing fixed time-of-use electricity price mechanism in meeting the energy demand of heterogeneous users at various moments or motivating users,the design of a reasonable dynamic pricing mechanism to actively engage users in demand response becomes imperative for power grid companies.For this purpose,a power grid-flexible load bilevel model is constructed based on dynamic pricing,where the leader is the dispatching center and the lower-level flexible load acts as the follower.Initially,an upper-level day-ahead dispatching model for the power grid is established,considering the lowest power grid dispatching cost as the objective function and incorporating the power grid-side constraints.Then,the lower level comprehensively considers the load characteristics of industrial load,energy storage,and data centers,and then establishes a lower-level flexible load operation model with the lowest user power-consuming cost as the objective function.Finally,the proposed method is validated using the IEEE-118 system,and the findings indicate that the dynamic pricing mechanism for peaking shaving and valley filling can effectively guide users to respond actively,thereby reducing the peak-valley difference and decreasing users’purchasing costs. 展开更多
关键词 Demand response fixed time-of-use electricity price mechanism dynamic price incentives mechanism bi-level model flexible load
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Investigating the dynamic mechanical behaviors of polyurea through experimentation and modeling 被引量:13
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作者 Hao Wang Ximin Deng +3 位作者 Haijun Wu Aiguo Pi Jinzhu Li Fenglei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第6期875-884,共10页
Polyurea is widely employed as a protective coating in many fields because of its superior ability to improve the anti-blast and anti-impact capability of structures.In this study,the mechanical properties of polyurea... Polyurea is widely employed as a protective coating in many fields because of its superior ability to improve the anti-blast and anti-impact capability of structures.In this study,the mechanical properties of polyurea XS-350 were investigated via systematic experimentation over a wide range of strain rates(0.001-7000 s^-1)by using an MTS,Instron VHS,and split-Hopkinson bars.The stress-strain behavior of polyurea was obtained for various strain rates,and the effects of strain rate on the primary mechanical properties were analyzed.Additionally,a modified rate-dependent constitutive model is proposed based on the nine-parameter Mooney-Rivlin model.The results show that the stress-strain curves can be divided into three distinct regions:the linear-elastic stage,the highly elastic stage,and an approximate linear region terminating in fracture.The mechanical properties of the polyurea material were found to be highly dependent on the strain rate.Furthermore,a comparison between model predictions and the experimental stress-strain curves demonstrated that the proposed model can characterize the mechanical properties of polyurea over a wide range of strain rates. 展开更多
关键词 POLYUREA Strain rate effect Dynamic mechanical properties Constitutive model
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Long-term mechanical behavior and characteristics of cemented tailings backfill through impact loading 被引量:8
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作者 Yu-ye Tan Elmo Davide +2 位作者 Yu-cheng Zhou Wei-dong Song Xiang Meng 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2020年第2期140-151,共12页
Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to di... Cemented tailings backfill(CTB)structures are important components of underground mine stopes.It is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and blasting.In this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of CTB.The stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and characteristics.For instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically loaded.These findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost. 展开更多
关键词 cyclic impact loading cemented tailings backfill dynamic mechanical properties Split-Hopkinson pressure bar dynamic peak
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Dynamical Mechanisms of Effects of Landslides on Long Distance Oil and Gas Pipelines 被引量:7
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作者 MA Qingwen WANG Chenghua KONG Jiming 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第4期820-824,共5页
According to the investigations on the oil and gas pipelines such as the Lan-Cheng-Chong pipeline and the Southwest pipeline, there are two ways of laying pipeline: pipelines paralleling (approximately) to the main... According to the investigations on the oil and gas pipelines such as the Lan-Cheng-Chong pipeline and the Southwest pipeline, there are two ways of laying pipeline: pipelines paralleling (approximately) to the main slide direction and pipelines perpendicular (approximately) to the main slide direction. If earth-retaining walls have been built for pipelines paralleling to the main slide direction, they will prevent the lands from sliding; On the contrary, without earth-retaining walls, the sharp broken rocks in the backfilling soil will scratch the safeguard of the pipeline when the landslides take place. Pipelines perpendicular to the main slide direction can be classified into four types according to the relative positions between pipelines and landslides: Pipelines over the slide planes, pipelines inside the fracture strips of slide planes, pipelines below the slide planes and pipelines behind the backsides of landslides. The different dynamical mechanisms of the process in which landslide acts against pipelines are analyzed based on whether the pipelines are equipped with fixed frusta, because the sliding resistance depends on whether and how many fixed frusta are equipped and the distance between frusta. 展开更多
关键词 LANDSLIDE long distance oil and gas pipeline dynamical mechanism
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Dynamic Mechanical Behavior of a Novel Polymeric Composite Damping Material 被引量:3
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作者 Cheng ZHANG Jiang Feng SHENG Chun An MA 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第11期1527-1530,共4页
The dynamic mechanical behavior of a novel polymeric composite damping material has been investigated in this article. The composite consists of chlorinated polyethylene (CPE), N,N-dicyclohexyl-2-benzothiazolylsufen... The dynamic mechanical behavior of a novel polymeric composite damping material has been investigated in this article. The composite consists of chlorinated polyethylene (CPE), N,N-dicyclohexyl-2-benzothiazolylsufenamide (DZ), 4,4'-thio-bis(3-methyl-6-tert-buthylphenol) (BPSR) and vapor-grown carbon fiber (VGCF). It is found that either the position or the intensity of damping peak can be controlled by changing the composition of CPE/DZ/BPSR composite. Within a certain composition region, damping peak maximum depends on CPE/DZ ratio, whereas damping peak position is controlled by BPSR content. Moreover, the improvement of storage modulus can be achieved by incorporation of VGCF. These results may imply that a damping material possessing both good damping properties and high strength can be designed and obtained. 展开更多
关键词 Dynamic mechanical behavior polymeric composite damping material.
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An experimental study on the relationship between acoustic parameters and mechanical properties of frozen silty clay 被引量:5
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作者 Xing Huang DongQing Li +1 位作者 Feng Ming JianHong Fang 《Research in Cold and Arid Regions》 CSCD 2013年第5期596-602,共7页
To study the influence of temperature and water content on ultrasonic wave velocity and to establish the relationship between ultrasonic wave velocity and frozen silty clay strength, ultrasonic tests were conducted to... To study the influence of temperature and water content on ultrasonic wave velocity and to establish the relationship between ultrasonic wave velocity and frozen silty clay strength, ultrasonic tests were conducted to frozen silty clay by using RSM-SY5(T) nonmetal supersonic test meter, and the tensile strength and compressive strength of silty clay were measured under various negative temperatures. Test and analysis results indicate that, ultrasonic wave velocity rapidly changes in the temperature range of-1 ℃ to -5 ℃. Ultrasonic wave velocity increased with an increase of water content until the water content reached the critical water content, while decreased with an increase of water content after the water content exceeded the critical water content. This study showed that there was strong positive correlation between the ul- trasonic wave velocity and the frozen soil strength. As ultrasonic wave velocity increased, either tensile strength or com- pressive strength increased. Based on the experimental data, the relationship between ultrasonic wave velocity and frozen silty clay strength was obtained through regression analysis. It was found that the ultrasonic test technique can be used to test frozen soils and lay the foundation for the determination of frozen soil strength. 展开更多
关键词 artificially frozen soil frozen soil strength ultrasonic wave velocity critical water content dynamic elastic mechanical parameters
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