期刊文献+
任意字段
题名或关键词
题名
关键词
摘要
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息
共找到41篇文章
< 1 2 3 >
每页显示 20 50 100
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
显示方式：
Semi-analytical modeling of tokamak density evolution 认领 引用 被引量：2
1
作者 石秉仁 《Chinese Physics B》 SCIE EI CAS 2010年第6期385-392,共8页
Tokamak plasma density evolution is generally modeled by a diffusion-convection equation in cylindrical geometry. By using a semi-analytical approach, we solve such an equation for a given diffusion coefficient and in... Tokamak plasma density evolution is generally modeled by a diffusion-convection equation in cylindrical geometry. By using a semi-analytical approach, we solve such an equation for a given diffusion coefficient and inward convection velocity as an arbitrary function of the radial position. Through variable separation, a Sturm-Liouville-type eigenvalue problem is solved, thereby constructing a complete set of orthogonal eigenfunctions. Based on the decomposition of the solution, the initial function, and the source function in these eigenfunctions, several problems of practical interest about the density evolution are analyzed. They include the density evolution, with boundary density not being zero; the density profile with internal transport barrier; the damping profile during particle source being shut-down. Results are found to be qualitatively consistent with the tokamak experiments. 展开更多
关键词 tokamak density evolution semi-analytical approach particle transport barrier
暂未订购 下载PDF
Probabilistic Response and Short-Term Extreme Load Estimation of Offshore Monopile Wind Turbine Towers by Probability Density Evolution Method 认领 引用
2
作者 ZHANG Hui XU Ya-zhou 《China Ocean Engineering》 SCIE EI CSCD 2022年第3期363-371,共9页
A new analysis framework based on probability density evolution method(PDEM)and its Chebyshev collocation solution are introduced to predict the dynamic response and short-term extreme load of offshore wind turbine(OW... A new analysis framework based on probability density evolution method(PDEM)and its Chebyshev collocation solution are introduced to predict the dynamic response and short-term extreme load of offshore wind turbine(OWT)towers subjected to random sea state.With regard to the stochastic responses,random function method is employed to generate samples of sea elevation,the probability density evolution equation(PDEE)is solved to calculate time-variant probability density functions of structural responses.For the probabilistic load estimation,a FAST model of NREL 5MW offshore turbine is established to obtain samples of bending moment at the tower base.The equivalent extreme event theory is used to construct a virtual stochastic process(VSP)to assess the short-term extreme load.The results indicate that the proposed approach can predict time-variant probability density functions of the structural responses,and shows good agreement with Monte Carlo simulations.Additionally,the predicted short-term extreme load can capture the fluctuation at the tail of the extreme value distribution,thus is more rational than results from the typical distribution models.Overall,the proposed method shows good adaptation,precision and efficiency for the dynamic response analysis and load estimation of OWT towers. 展开更多
关键词 offshore wind turbine probability density evolution method Chebyshev collocation matrix exponential Monte Carlo
暂未订购 下载PDF
Operator Semi-group of Density Evolution Equation for a Repairable Redundant System with Two Same Components 认领 引用
3
作者 史定华 徐洪 +1 位作者 熊勇 王远第 《Journal of Shanghai University(English Edition)》 2002年第4期278-281,共4页
For a repairable redundant system consisting of two same components with exponential lifetime and general repair time distribution, the probability densities of the system in some state at time t were determined by a ... For a repairable redundant system consisting of two same components with exponential lifetime and general repair time distribution, the probability densities of the system in some state at time t were determined by a group of ordinary and partial differential equations, called density evolution equations. It was proved that the time dependent solution of the density evolution equations uniquely exists and strongly converges to its steady state density solution by a semi group method. In this proof, it is not necessary to suppose that the repair rate function is bounded. The technique of the proof is valuable for many density evolution equations. 展开更多
关键词 stochastic model repairable redundant system density evolution equation C 0 semi group.
暂未订购 下载PDF
C_0-Semigroup Method of the Density Evolution Equation for M/M/∞ Model 认领 引用
4
作者 SHI Ding hua, XIONG Yong, XU Hong College of Sciences, Shanghai University, Shanghai 200436, China 《Journal of Shanghai University(English Edition)》 2001年第4期265-268,共4页
In this paper, the existence, uniqueness, and asymptotic behavior of the solution of the density evolution equation for M/M/∞ model was studied by the semigroup theory of linear operators.
关键词 M/M/∞ model density evolution equation C 0-semigroup
暂未订购 下载PDF
High-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer based on probability density evolution method 认领 引用 被引量：4
5
作者 Mingming Wang Linfang Qian +3 位作者 Guangsong Chen Tong Lin Junfei Shi Shijie Zhou 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2024年第2期209-221,共13页
This paper proposed an efficient research method for high-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer.Firstly,the dynamic model of projectile motion is establi... This paper proposed an efficient research method for high-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer.Firstly,the dynamic model of projectile motion is established considering the flexible deformation of the barrel and the interaction between the projectile and the barrel.Subsequently,the accuracy of the dynamic model is verified based on the external ballistic projectile attitude test platform.Furthermore,the probability density evolution method(PDEM)is developed to high-dimensional uncertainty quantification of projectile motion.The engineering example highlights the results of the proposed method are consistent with the results obtained by the Monte Carlo Simulation(MCS).Finally,the influence of parameter uncertainty on the projectile disturbance at muzzle under different working conditions is analyzed.The results show that the disturbance of the pitch angular,pitch angular velocity and pitch angular of velocity decreases with the increase of launching angle,and the random parameter ranges of both the projectile and coupling model have similar influence on the disturbance of projectile angular motion at muzzle. 展开更多
关键词 Truck-mounted howitzer Projectile motion Uncertainty quantification Probability density evolution method
暂未订购 下载PDF
Prediction and Output Estimation of Pattern Moving in Non-Newtonian Mechanical Systems Based on Probability Density Evolution 认领 引用
6
作者 Cheng Han Zhengguang Xu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期515-536,共22页
A prediction framework based on the evolution of pattern motion probability density is proposed for the output prediction and estimation problem of non-Newtonian mechanical systems,assuming that the system satisfies t... A prediction framework based on the evolution of pattern motion probability density is proposed for the output prediction and estimation problem of non-Newtonian mechanical systems,assuming that the system satisfies the generalized Lipschitz condition.As a complex nonlinear system primarily governed by statistical laws rather than Newtonian mechanics,the output of non-Newtonian mechanics systems is difficult to describe through deterministic variables such as state variables,which poses difficulties in predicting and estimating the system’s output.In this article,the temporal variation of the system is described by constructing pattern category variables,which are non-deterministic variables.Since pattern category variables have statistical attributes but not operational attributes,operational attributes are assigned to them by posterior probability density,and a method for analyzing their motion laws using probability density evolution is proposed.Furthermore,a data-driven form of pattern motion probabilistic density evolution prediction method is designed by combining pseudo partial derivative(PPD),achieving prediction of the probability density satisfying the system’s output uncertainty.Based on this,the final prediction estimation of the system’s output value is realized by minimum variance unbiased estimation.Finally,a corresponding PPD estimation algorithm is designed using an extended state observer(ESO)to estimate the parameters to be estimated in the proposed prediction method.The effectiveness of the parameter estimation algorithm and prediction method is demonstrated through theoretical analysis,and the accuracy of the algorithm is verified by two numerical simulation examples. 展开更多
关键词 Non-newtonian mechanical systems prediction and estimation pattern moving probability density evolution pseudo partial derivative
暂未订购 下载PDF
Three-Dimensional van Hove Singularities and Charge Density Wave Evolution in Kagome Lattice KV3Sb5 认领 引用
7
作者 Yu Huang Haiyang Ma +13 位作者 Wei Xia Zhicheng Jiang Wenchuan Jing Xiangqi Liu Jiayu Liu Yuming Shi Xun Ma Runfeng Zhang Jin-Feng Jia Jishan Liu Mao Ye Zhengtai Liu Yanfeng Guo Dawei Shen 《Chinese Physics Letters》 SCIE EI CAS CSCD 2025年第12期226-238,共13页
The kagome metals AV3Sb5(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena... The kagome metals AV3Sb5(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena such as charge density waves(CDW)and superconductivity.Although the vHS from V 3d states have been implicated in CDW formation,their three-dimensional nature and temperature evolution remain poorly understood.In this study,we used high-resolution angle-resolved photoemission spectroscopy and density functional theory to reveal pronounced out-of-plane dispersion of vHS and their temperature dependence in KV3Sb5.The identified c-axis band folding and scattering channels were directly linked to the CDW order.These results demonstrate that the CDW transition in this family involves cooperative coupling between electron correlations and structural modulation along the c axis.This offers new insights into the interplay of topology,correlations,and lattice instabilities in kagome metals. 展开更多
关键词 kagome metals dirac fermionstopological flat bandsand van hove singularities vhs near charge density waves cdw three dimensional van hove singularities kv sb c axis band folding charge density wave evolution
暂未订购 下载PDF
Moment-independent importance measure of basic random variable and its probability density evolution solution 认领 引用 被引量：46
8
作者 CUI LiJie LüZhenZhou ZHAO XinPan 《Science China(Technological Sciences)》 SCIE EI CAS 2010年第4期1138-1145,共8页
To analyze the effect of basic variable on failure probability in reliability analysis,a moment-independent importance measure of the basic random variable is proposed,and its properties are analyzed and verified.Base... To analyze the effect of basic variable on failure probability in reliability analysis,a moment-independent importance measure of the basic random variable is proposed,and its properties are analyzed and verified.Based on this work,the importance measure of the basic variable on the failure probability is compared with that on the distribution density of the response.By use of the probability density evolution method,a solution is established to solve two importance measures,which can efficiently avoid the difficulty in solving the importance measures.Some numerical examples and engineering examples are used to demonstrate the proposed importance measure on the failure probability and that on the distribution density of the response.The results show that the proposed importance measure can effectively describe the effect of the basic variable on the failure probability from the distribution density of the basic variable.Additionally,the results show that the established solution on the probability density evolution is efficient for the importance measures. 展开更多
关键词 basic random variable moment-independent importance measure probability density evolution method
暂未订购 下载PDF
Typhoon hazard assessment at the site-specific scale based on the probability density evolution method and its application on the southeast coast of China 认领 引用
9
作者 HONG Xu LI Jie 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2023年第1期86-100,共15页
Herein, a typhoon hazard assessment method at the site-specific scale is proposed. This method integrates the nonlinear threedimensional wind field model and the probability density evolution method. At the site-speci... Herein, a typhoon hazard assessment method at the site-specific scale is proposed. This method integrates the nonlinear threedimensional wind field model and the probability density evolution method. At the site-specific scale, the track of a typhoon near the engineering site is approximated via a straight line. The wind field model is utilized to calculate the wind speed at the surface given the gradient wind field at the top of the boundary layer. A comparison between the simulated and observed wind histories for Typhoon Hagupit that made landfall in Guangdong Province demonstrates the fidelity of the wind field model. The probability density evolution method is utilized to calculate the propagation of the randomness from the basic random variables toward the extremities of the typhoon surface wind. To model the probability distribution of the basic random variables, several candidate distributions are considered to fit the observations. Akaike information criterion and Anderson-Darling distance are used for selecting the preferred probability distribution model. The adequacy of the probability density evolution method in assessing typhoon hazards is verified by comparing the results with those generated by Monte Carlo simulations. The typhoon wind hazards estimated by the present study are compared with those proposed by other studies and the design code, and the differences are analyzed and discussed. The results of the proposed method provide the reasonable probabilistic model for the assessment of the structural reliability and the improvement of community resilience in the typhoon-prone areas. 展开更多
关键词 typhoon hazard Akaike information criterion Anderson-Darling distance boundary-layer wind field probability density evolution method
暂未订购 下载PDF
A physics-based probabilistic method for assessment of landslide-induced wave run-up hazards 认领 引用 被引量：2
10
作者 Ningjie Li Xinli Hu +3 位作者 Jian Wang Junxiang Huang Hongchao Zheng Wei Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第5期3675-3687,共13页
Traditional deterministic numerical simulation often has a poor prediction performance for landslide-induced wave run-up(LIWR)hazards,as it neglects the effects of uncertainty.The limitation for efficiently quantifyin... Traditional deterministic numerical simulation often has a poor prediction performance for landslide-induced wave run-up(LIWR)hazards,as it neglects the effects of uncertainty.The limitation for efficiently quantifying the uncertainties in primary parameters remains largely unsolved.In this study,we propose a probabilistic evaluation method,integrating the adaptive Kriging(AK)metamodel method and probability density evolution method(PDEM)based on generalized F-discrepancy.A Taylor expansion-based adaptive design strategy is applied to construct the global AK model over representative points generated by generalized F-discrepancy,thereby approximating the numerical physical response(i.e.,maximum LIWR).Using these approximate responses,the PDEM is used to compute the exceedance probabilities that LIWR heights exceed elements at risk based on a construction of virtual time,and then a probabilistic criterion is introduced to classify hazard zones.The proposed method is demonstrated via two examples:Example I,which possesses risk element(building),and Example Ⅱ with water-level variations.The results indicate that the proposed method has an acceptable performance(showing a 1.7%difference in exceedance probability compared to Monte Carlo simulation with 50,000 samples)with low computation cost(requiring 284 deterministic analyses).For two specific scenarios in this study,the wave induced by the landslide exhibits a solitary-like leading wave.The proposed probabilistic method provides promising prospects for quantifying LIWR uncertainties,and is helpful for direct,efficient,and low-cost quantification assessment of cascading hazards. 展开更多
关键词 Landslide-induced wave run-up(LIWR) Numerical simulation Adaptive metamodel Probability density evolution method(PDEM) Hazard zoning
暂未订购 下载PDF
A full information expression model for track irregularity based on stochastic harmonic functions in vehicle-turnout structure stochastic vibration analysis 认领 引用 被引量：1
11
作者 Xueyang Tang Xiaopei Cai +1 位作者 Jingmang Xu Fei Yang 《Railway Engineering Science》 EI 2026年第2期349-369,共21页
Turnout irregularity significantly affects the stochastic vibration behavior of vehicle-turnout structures.This study proposes a fitting formula for the turnout irregularity spectrum and develops a turnout irregularit... Turnout irregularity significantly affects the stochastic vibration behavior of vehicle-turnout structures.This study proposes a fitting formula for the turnout irregularity spectrum and develops a turnout irregularity full information expression model(TIFIEM)using a stochastic harmonic function.The model is applied to vehicle-turnout structure stochastic vibration and reliability analysis.Findings suggest that the Hamming window method,with a window length of 4096 points,is optimal for estimating the turnout irregularity spectrum.It is recommended to fit the power spectral density(PSD)using a 5th-order polynomial for better accuracy.The TIFIEM effectively addresses randomness in amplitude,frequency,and phase.An analysis of 250 irregularity samples is sufficient for the desired accuracy.Additionally,the PSD amplitude at various frequency points follows a Chi-square distribution with 2°of freedom.Regions 3-7 m from the tip of the switch rail on the straight switch rail and 53-54 m on the point rail are most susceptible to wear.When the vehicle passes through the turnout at 300 km/h,the reliability of vehicle-turnout structures at the crossing panel decreases to 95.8%. 展开更多
关键词 High-speed railway Vehicle-turnout coupling dynamics Turnout irregularity spectrum Stochastic harmonic function Probability density evolution method
暂未订购 下载PDF
Joint probability density function of the stochastic responses of nonlinear structures 认领 引用 被引量：3
12
作者 陈建兵 李杰 《Earthquake Engineering and Engineering Vibration》 SCIE EI 2007年第1期35-47,共13页
The joint probability density fimction （PDF） of different structural responses is a very important topic in the stochastic response analysis of nonlinear structures. In this paper, the probability density evolution ... The joint probability density fimction （PDF） of different structural responses is a very important topic in the stochastic response analysis of nonlinear structures. In this paper, the probability density evolution method, which is successfully developed to capture the instantaneous PDF of an arbitrary single response of interest, is extended to evaluate the joint PDF of any two responses. A two-dimensional partial differential equation in terms of the joint PDF is established. The strategy of selecting representative points via the number theoretical method and sieved by a hyper-ellipsoid is outlined. A two-dimensional difference scheme is developed. The free vibration of an SDOF system is examined to verify the proposed method, and a flame structure exhibiting hysteresis subjected to stochastic ground motion is investigated. It is pointed out that the correlation of different responses results from the fact that randomness of different responses comes from the same set of basic random parameters involved. In other words, the essence of the probabilistic correlation is a physical correlation. 展开更多
关键词 stochastic response nonlinearity joint probability density function probability density evolution method number theoretical method finite difference method
暂未订购 下载PDF
Implementation of low-density parity-check codes decoder for CCSDS standard 认领 引用 被引量：1
13
作者 李晓枫 安思宁 詹天祥 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期538-542,共5页
The complexity/performance balanced decoder for low-density parity-check （LDPC） codes is preferred in practical wireless communication systems. A low complexity LDPC decoder for the Consultative Committee for Space ... The complexity/performance balanced decoder for low-density parity-check （LDPC） codes is preferred in practical wireless communication systems. A low complexity LDPC decoder for the Consultative Committee for Space Data Systems （CCSDS） standard is achieved in DSP. An ap- proximate decoding algorithm, normalized rain-sum algorithm, is used in the implementation for its low amounts of computation. To reduce the performance loss caused by the approximation, the pa- rameters of the normalized min-sum algorithm are determined by calculating and finding the mini- mum value of thresholds through density evolution. The minimum value which indicates the best per- formance of the decoding algorithm is corresponding with the optimized parameters. In implementa- tion, the memory cost is saved by decomposing the parity-check matrix into submatrices to store and the computation of passing message in decoding is accelerated by using the intrinsic function of DSP. The performance of the decoder with optimized factors is simulated and compared with the ideal BP decoder. The result shows they have about the same performance. 展开更多
关键词 low-density parity-check （LDPC） decoder normalized min-sum digital signal proces-sor （DSP） implementation density evolution
暂未订购 下载PDF
Substructure Evolution of Ti-6Al-2Zr-1Mo-1V Alloy Isothermally Hot Compressed in α+β Two-Phase Region 认领 引用 被引量：2
14
作者 Chuan WU He YANG Hongwei LI 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2013年第5期533-544,共12页
Substructure evolution significantly influences the flow behavior of titanium alloys in isothermal hot compression. This paper presents a physical experiment（isothermal hot compression and electron backscatter difrac... Substructure evolution significantly influences the flow behavior of titanium alloys in isothermal hot compression. This paper presents a physical experiment（isothermal hot compression and electron backscatter difraction, EBSD） and a cellular automaton（CA） method to investigate the substructure evolution of a near-α titanium alloy Ti-6Al-2Zr-1Mo-1V（TA15） isothermally compressed in the α ＋ β two-phase region. In the CA model, the subgrain growth, the transformation of low angle boundaries（LABs） to high angle boundaries（HABs） and the dislocation density evolution were considered. The dislocation density accumulating around the subgrain boundaries provided a driving force and made the transformation of the LABs to HABs. The CA model was employed to predict the substructure evolution, dislocation density evolution and flow stress. In addition, the efects of strain, strain rate and temperature on the relative frequency of the HABs were analyzed and discussed. To verify the CA model, the predicted results including the relative frequency of the HABs and the flow stress were compared with the experimental values. 展开更多
关键词 Substructure evolution Cellular automaton modeling Dislocation density evolution EBSD technique
暂未订购 下载PDF
Phase Evolution Study and Optimization of the Heat Treatment Process for High Current Capacity Bi-2223 Tapes 认领 引用 被引量：1
15
作者 白利锋 张胜楠 +3 位作者 LI Chengshan HAO Qingbin LIU Guoqing ZHANG Pingxiang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第4期862-865,共4页
Powder in tube process（PIT） was adopted for the fabrication of single filament Bi-2223 tapes, and a heat treatment process including the first heat treatment（HT1）, intermediate rolling（IR）, and second heat treat... Powder in tube process（PIT） was adopted for the fabrication of single filament Bi-2223 tapes, and a heat treatment process including the first heat treatment（HT1）, intermediate rolling（IR）, and second heat treatment（HT2） was performed. The phase evolution mechanism and microstructure changes during these heat treatment processes were systematically discussed. The influences of HT1 parameters on the phase evolution process of Bi-2223 tapes were discussed. With the optimized HT1 process, a proper Bi-2223 content of about 90% was achieved. HT2 process was also optimized by adding a post annealing process. An obvious increase of current capacity was obtained due to the enhancement of intergrain connections. Single filament Bi-2223 tapes with the critical current of Ic-90 A were fabricated with the optimized sintering process. 展开更多
关键词 high temperature superconductor Bi-2223 phase evolution spray drying critical current density
暂未订购 下载PDF
Wind⁃resistant fuzzy comfortability assessment for a super⁃high tower crane based on the PDEM 认领 引用 被引量：4
16
作者 LIU Yun WANG Hao +2 位作者 LI Bing XU Zidong MAO Jianxiao 《Journal of Southeast University(English Edition)》 EI CAS 2025年第1期51-57,共7页
The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency.Therefore,the wind-resistant fuzzy comfortability of a super-high tower ... The fuzzy comfortability of a wind-sensitive super-high tower crane is critical to guarantee occupant health and improve construction efficiency.Therefore,the wind-resistant fuzzy comfortability of a super-high tower crane in the Ma’anshan Yangtze River(MYR)Bridge site is analyzed in this paper.First,the membership function model that represents fuzzy comfortability is introduced in the probability density evolution method(PDEM).Second,based on Fechner’s law,the membership function curves are constructed according to three acceleration thresholds in ISO 2631.Then,the fuzzy comfortability for the super-high tower crane under stochastic wind loads is assessed on the basis of different cut-set levelsλ.Results show that the comfortability is over 0.9 under the required maximum operating wind velocity.The low sensitivity toλcan be observed in the reliability curves of ISOⅡandⅢmembership functions.The reliability of the ISOⅠmembership function is not sensitive toλwhenλ0.7. 展开更多
关键词 comfort reliability probability density evolution method fuzzy theory membership function tower crane long-span bridge
暂未订购 下载PDF
Simulated and experimental investigation on discontinuous dynamic recrystallization of a near-α TA15 titanium alloy during isothermal hot compression in βsingle-phase field 认领 引用 被引量：10
17
作者 武川 杨合 李宏伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1819-1829,共11页
A cellular automaton（CA） modeling of discontinuous dynamic recrystallization（DDRX） of a near-α Ti-6Al-2Zr-1Mo-1V（TA15） isothermally compressed in the β single phase field was presented.In the CA model,nucleati... A cellular automaton（CA） modeling of discontinuous dynamic recrystallization（DDRX） of a near-α Ti-6Al-2Zr-1Mo-1V（TA15） isothermally compressed in the β single phase field was presented.In the CA model,nucleation of the β-DDRX and the growth of recrystallized grains（re-grains） were considered and visibly simulated by the CA model.The driving force of re-grain growth was provided by dislocation density accumulating around the grain boundaries.To verify the CA model,the predicted flow stress by the CA model was compared with the experimental data.The comparison showed that the average relative errors were10.2%,10.1%and 6%,respectively,at 1.0,0.1 and 0.01 s^-1 of 1020 ℃,and were 10.2%,11.35%and 7.5%,respectively,at 1.0,0.1and 0.01 s^-1 of 1050 ℃.The CA model was further applied to predicting the average growth rate,average re-grain size and recrystallization kinetics.The simulated results showed that the average growth rate increases with the increasing strain rate or temperature,while the re-grain size increases with the decreasing strain rate;the volume fraction of recrystallization decreases with the increasing strain rate or decreasing temperature. 展开更多
关键词 discontinuous dynamic recrystallization cellular automaton dislocation density evolution recrystallization kinetics TA15 titanium alloy
暂未订购 下载PDF
A novel refined dynamic model of high-speed maglev train-bridge coupled system for random vibration and running safety assessment 认领 引用 被引量：4
18
作者 MAO Jian-feng LI Dao-hang +3 位作者 YU Zhi-wu CAI Wen-feng GUO Wei ZHANG Guang-wen 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2532-2544,共13页
Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can b... Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval. 展开更多
关键词 maglev train-bridge interaction electromagnetic force-air gap model stochastic dynamic analysis running safety assessment probability density evolution method
暂未订购 下载PDF
Uncertainty quantification of mechanism motion based on coupled mechanism—motor dynamic model for ammunition delivery system 认领 引用 被引量：3
19
作者 Jinsong Tang Linfang Qian +3 位作者 Longmiao Chen Guangsong Chen Mingming Wang Guangzu Zhou 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2024年第3期125-133,共9页
In this paper,a dynamic modeling method of motor driven electromechanical system is presented,and the uncertainty quantification of mechanism motion is investigated based on this method.The main contribution is to pro... In this paper,a dynamic modeling method of motor driven electromechanical system is presented,and the uncertainty quantification of mechanism motion is investigated based on this method.The main contribution is to propose a novel mechanism-motor coupling dynamic modeling method,in which the relationship between mechanism motion and motor rotation is established according to the geometric coordination of the system.The advantages of this include establishing intuitive coupling between the mechanism and motor,facilitating the discussion for the influence of both mechanical and electrical parameters on the mechanism,and enabling dynamic simulation with controller to take the randomness of the electric load into account.Dynamic simulation considering feedback control of ammunition delivery system is carried out,and the feasibility of the model is verified experimentally.Based on probability density evolution theory,we comprehensively discuss the effects of system parameters on mechanism motion from the perspective of uncertainty quantization.Our work can not only provide guidance for engineering design of ammunition delivery mechanism,but also provide theoretical support for modeling and uncertainty quantification research of mechatronics system. 展开更多
关键词 Ammunition delivery system Electromechanical coupling dynamics Uncertainty quantification Generalized probability density evolution
暂未订购 下载PDF
Extreme value distribution and reliability of nonlinear stochastic structures 认领 引用 被引量：9
20
作者 陈建兵 李杰 《Earthquake Engineering and Engineering Vibration》 EI 2005年第2期275-286,共12页
A new approach to evaluate the extreme value distribution （EVD） of the response and reliability of general multi-DOF nonlinear stochastic structures is proposed. The approach is based on the recently developed proba... A new approach to evaluate the extreme value distribution （EVD） of the response and reliability of general multi-DOF nonlinear stochastic structures is proposed. The approach is based on the recently developed probability density evolution method, which enables the instantaneous probability density functions of the stochastic responses to be captured. In the proposed method, a virtual stochastic process is first constructed to satisfy the condition that the extreme value of the response equals the value of the constructed process at a certain instant of time. The probability density evolution method is then applied to evaluate the instantaneous probability density function of the response, yielding the EVD. The reliability is therefore available through a simple integration over the safe domain. A numerical algorithm is developed using the Number Theoretical Method to select the discretized representative points. Further, a hyper-ball is imposed to sieve the points from the preceding point set in the hypercube. In the numerical examples, the EVD of random variables is evaluated and compared with the analytical solution. A frame structure is analyzed to capture the EVD of the response and the dynamic reliability. The investigations indicate that the proposed approach provides reasonable accuracy and efficiency. 展开更多
关键词 extreme value distribution reliability nonlinear probability density evolution method number theoreticalmethod
暂未订购 下载PDF
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
上一页 1 2 3 下一页 到第 页
在线咨询 使用帮助 返回顶部 意见反馈