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An approach for determination of lateral limit angle in kinematic planar sliding analysis for rock slopes
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作者 Xiaojuan Yang Jie Hu +1 位作者 Honglei Sun Jun Zheng 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第4期1305-1314,共10页
Planar sliding is one of the frequently observed types of failure in rock slopes.Kinematic analysis is a classic and widely used method to examine the potential failure modes in rock masses.The accuracy of planar slid... Planar sliding is one of the frequently observed types of failure in rock slopes.Kinematic analysis is a classic and widely used method to examine the potential failure modes in rock masses.The accuracy of planar sliding kinematic analysis is significantly influenced by the value assigned to the lateral limit angleγlim.However,the assignment ofγlim is currently used generally based on an empirical criterion.This study aims to propose an approach for determining the value ofγlim in deterministic and probabilistic kinematic planar sliding analysis.A new perspective is presented to reveal thatγlim essentially influences the probability of forming a potential planar sliding block.The procedure to calculate this probability is introduced using the block theory method.It is found that the probability is correlated with the number of discontinuity sets presented in rock masses.Thus,different values ofγlim for rock masses with different sets of discontinuities are recommended in both probabilistic and deterministic planar sliding kinematic analyses;whereas a fixed value ofγlim is commonly assigned to different types of rock masses in traditional method.Finally,an engineering case was used to compare the proposed and traditional kinematic analysis methods.The error rates of the traditional method vary from 45%to 119%,while that of the proposed method ranges between 1%and 17%.Therefore,it is likely that the proposed method is superior to the traditional one. 展开更多
关键词 Kinematic analysis Block theory Planar sliding Lateral limit angle Rock slope
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AHermitian C^(2) Differential Reproducing Kernel Interpolation Meshless Method for the 3D Microstructure-Dependent Static Flexural Analysis of Simply Supported and Functionally Graded Microplates
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作者 Chih-Ping Wu Ruei-Syuan Chang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期917-949,共33页
This work develops a Hermitian C^(2) differential reproducing kernel interpolation meshless(DRKIM)method within the consistent couple stress theory(CCST)framework to study the three-dimensional(3D)microstructuredepend... This work develops a Hermitian C^(2) differential reproducing kernel interpolation meshless(DRKIM)method within the consistent couple stress theory(CCST)framework to study the three-dimensional(3D)microstructuredependent static flexural behavior of a functionally graded(FG)microplate subjected to mechanical loads and placed under full simple supports.In the formulation,we select the transverse stress and displacement components and their first-and second-order derivatives as primary variables.Then,we set up the differential reproducing conditions(DRCs)to obtain the shape functions of the Hermitian C^(2) differential reproducing kernel(DRK)interpolant’s derivatives without using direct differentiation.The interpolant’s shape function is combined with a primitive function that possesses Kronecker delta properties and an enrichment function that constituents DRCs.As a result,the primary variables and their first-and second-order derivatives satisfy the nodal interpolation properties.Subsequently,incorporating ourHermitianC^(2)DRKinterpolant intothe strong formof the3DCCST,we develop a DRKIM method to analyze the FG microplate’s 3D microstructure-dependent static flexural behavior.The Hermitian C^(2) DRKIM method is confirmed to be accurate and fast in its convergence rate by comparing the solutions it produces with the relevant 3D solutions available in the literature.Finally,the impact of essential factors on the transverse stresses,in-plane stresses,displacements,and couple stresses that are induced in the loaded microplate is examined.These factors include the length-to-thickness ratio,the material length-scale parameter,and the inhomogeneity index,which appear to be significant. 展开更多
关键词 Consistent/modified couple stress theory differential reproducing kernel methods microplates point collocation methods static flexural 3D microstructure-dependent analysis
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New Configurations of the Fuzzy Fractional Differential Boussinesq Model with Application in Ocean Engineering and Their Analysis in Statistical Theory
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作者 Yu-Ming Chu SaimaRashid +1 位作者 Shazia Karim Anam Sultan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第11期1573-1611,共39页
The fractional-order Boussinesq equations(FBSQe)are investigated in this work to see if they can effectively improve the situation where the shallow water equation cannot directly handle the dispersion wave.The fuzzy ... The fractional-order Boussinesq equations(FBSQe)are investigated in this work to see if they can effectively improve the situation where the shallow water equation cannot directly handle the dispersion wave.The fuzzy forms of analytical FBSQe solutions are first derived using the Adomian decomposition method.It also occurs on the sea floor as opposed to at the functionality.A set of dynamical partial differential equations(PDEs)in this article exemplify an unconfined aquifer flow implication.Thismethodology can accurately simulate climatological intrinsic waves,so the ripples are spread across a large demographic zone.The Aboodh transform merged with the mechanism of Adomian decomposition is implemented to obtain the fuzzified FBSQe in R,R^(n) and(2nth)-order involving generalized Hukuhara differentiability.According to the system parameter,we classify the qualitative features of the Aboodh transform in the fuzzified Caputo and Atangana-Baleanu-Caputo fractional derivative formulations,which are addressed in detail.The illustrations depict a comparison analysis between the both fractional operators under gH-differentiability,as well as the appropriate attributes for the fractional-order and unpredictability factorsσ∈[0,1].A statistical experiment is conducted between the findings of both fractional derivatives to prevent changing the hypothesis after the results are known.Based on the suggested analyses,hydrodynamic technicians,as irrigation or aquifer quality experts,may be capable of obtaining an appropriate storage intensity amount,including an unpredictability threshold. 展开更多
关键词 Fuzzy set theory aboodh transform adomian decomposition method boussinesq equation fractional derivative operators analysis of variance test
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Analysis of Young Girls’Eagerness to Spend for Disney Virtual Characters Based on Marketing Mix Theory
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作者 HUANG Xiaoyu 《Psychology Research》 2023年第4期188-194,共7页
A virtual character is a design of a fictitious creature with distinctive characteristics created by people,and Disney virtual characters are those Intellectual Property(IP)images that appeared in Disneyland and Disne... A virtual character is a design of a fictitious creature with distinctive characteristics created by people,and Disney virtual characters are those Intellectual Property(IP)images that appeared in Disneyland and Disney movies.This investigation aimed to explore why many younger females are keen to spend money on Disney virtual characters.This paper adopted the Marketing Mix Theory strategy(product,price,placement,and promotion(4P)),and the SWOT analysis method has been utilized.This paper investigated the relationship between the 4Ps and consumers’purchasing intentions,and it turned out that unique design and effective promotion in this Disney case would promote consumers’purchase intention,while the higher price and less accessible placements affected their purchase intentions.Thus,the high price and limited places somewhat inhibit customers’desire to buy;due to the attractiveness of the product itself and the promotion on the internet,the target consumers are still willing to consume. 展开更多
关键词 Marketing Mix theory 4P SWOT(strengths WEAKNESS opportunities threats)analysis DISNEY virtual characters
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ESTIMATION METHOD FOR AIRCRAFT SIMILARITY BASED ON FUZZY THEORY AND GREY INCIDENCE ANALYSIS 被引量:4
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作者 李永平 陈闵叶 刘明 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2007年第3期194-198,共5页
An estimation method for aircraft similarity based on fuzzy theory and grey incidence analysis is presented. This estimation method is made up of the triangular fuzzy transforming model of linguistic variables and the... An estimation method for aircraft similarity based on fuzzy theory and grey incidence analysis is presented. This estimation method is made up of the triangular fuzzy transforming model of linguistic variables and the method of grey incidence analysis. Nine feature attributes of aircraft are selected to estimate the similarity between the new aircraft and the existing aircraft. A new aircraft X and other six existing aircrafts are taken as examples. Analyses show that similarity estimation results obtained from the method are in accordance with practice. 展开更多
关键词 aircraft similarity fuzzy theory grey incidence analysis
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Analysis on the Theory of Blow-up and Verification on Numerical Prediction of Heavy Rain in Sichuan Basin
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作者 邓兵奎 《Meteorological and Environmental Research》 CAS 2010年第12期52-55,共4页
By dint of V-3θ diagram from the Blown-up theory,a continuous heavy rain process in western Sichuan basin from July 14 to 17,2009 is analyzed in this paper.Situation field and precipitation of ECWMF and T213 are veri... By dint of V-3θ diagram from the Blown-up theory,a continuous heavy rain process in western Sichuan basin from July 14 to 17,2009 is analyzed in this paper.Situation field and precipitation of ECWMF and T213 are verified and discussed.Results show that V-3θ diagram can describe the heavy rain process accurately.Combining with additional conventional weather charts,experience and numerical forecast products,the heavy rain falling area is determined.The forecast accuracy of situation field of EC is significantly higher than that of T213 and the forecast accuracy of T213 for heavy rain forecast is relatively low. 展开更多
关键词 Blown-up theory V-3θ diagram Western Sichuan obstructive model Interpretation and analysis Integrated Forecast China
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General Kinetostatic Modeling and Deformation Analysis of a Two-Module Rod-Driven Continuum Robot with Friction Considered 被引量:2
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作者 Peiyi Wang Xinhua Yang +1 位作者 Xiangyang Wang Sheng Guo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第3期110-122,共13页
Continuum robots actuated by flexible rods have large potential applications,such as detection and operation tasks in confined environments,since the push and pull actuation of flexible rods withstand tension and comp... Continuum robots actuated by flexible rods have large potential applications,such as detection and operation tasks in confined environments,since the push and pull actuation of flexible rods withstand tension and compressive force,and increase the structure's rigidity.In this paper,a generalized kinetostatics model for multi-module and multi-segment continuum robots considering the effect of friction based on the Cosserat rod theory is established.Then,the model is applied to a two-module rod-driven continuum robot with winding ropes to analyze its deformation and load characteristics.Four different in-plane configurations under the external load term as S1,S2,C1,and C2 are defined.Taking a bending plane as an example,the tip deformation along thex-axis of these shapes is simulated and compared,which shows that the load capacity of C1 and C2 is generally larger than that of S1 and S2.Furthermore,the deformation experiments and simulations show that the maximum error ratio without external loads relative to the total length is no more than 3%,and it is no more than 4.7%under the external load.The established kinetostatics model is proven sufficient to accurately analyze the rod-driven continuum robot with the consideration of internal friction. 展开更多
关键词 Rod-driven continuum robot Kinetostatic model Cosserat rod theory Deformation and stiffness analysis
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Analysis on the Application of Schema Theory to Improve English Listening Teaching Effectiveness 被引量:1
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作者 黄莹 《海外英语》 2013年第4X期17-18,21,共3页
Based on the schema theory,the paper analyzes the psychological cognitive process of listening comprehension.Schema theory provides a good theoretical basis to improve the English listening teaching effectiveness.Prac... Based on the schema theory,the paper analyzes the psychological cognitive process of listening comprehension.Schema theory provides a good theoretical basis to improve the English listening teaching effectiveness.Practice shows that the schema theory application to guide teaching practice can achieve great progress in an English listening classroom. 展开更多
关键词 SCHEMA theory LISTENING COMPREHENSION COGNITIVE an
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Cost-benefit analysis of esophageal cancer endoscopic screening in high-risk areas of China 被引量:33
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作者 Juan Yang wen-Qiang wei +3 位作者 Jin Niu Zhi-Cai Liu Chun-Xia Yang You-Lin Qiao 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第20期2493-2501,共9页
AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and th... AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and the benefit-cost ratios(BCRs)of 12 EC endoscopic screening strategies.Strategies varied according to the targeted screening age,screening frequencies,and follow-up intervals.Model parameters were collected from population-based studies in China,published literatures,and surveillance data. RESULTS:Compared with non-screening outcomes,all strategies with hypothetical 100 000 subjects saved life years.Among five dominant strategies determined by the incremental cost-effectiveness analysis,screening once at age 50 years incurred the lowest NPV(international dollar-I$55 million)and BCR(2.52).Screening six times between 40-70 years at a 5-year interval[i.e., six times(40)f-strategy]yielded the highest NPV(I$99 million)and BCR(3.06).Compared with six times(40)fstrategy,screening thrice between 40-70 years at a 10-year interval resulted in relatively lower NPV,but the same BCR. CONCLUSION:EC endoscopic screening is cost-beneficial in high-risk areas of China.Policy-makers should consider the cost-benefit,population acceptance,and local economic status when choosing suitable screening strategies. 展开更多
关键词 cost-benefit analysis Esophageal cancer ENDOSCOPY SCREENING High-risk area
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Theory of random energy analysis for train derailment 被引量:13
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作者 向俊 曾庆元 娄平 《Journal of Central South University of Technology》 2003年第2期134-139,共6页
Three fundamental problems in the calculation of train derailment abroad and at home were pointed out and the solutions to these problems were presented. The theory of random energy analysis for train derailment was s... Three fundamental problems in the calculation of train derailment abroad and at home were pointed out and the solutions to these problems were presented. The theory of random energy analysis for train derailment was suggested. The main contents of this theory are as follows: geometric criterion of derailment; method of random energy analysis of transverse vibration of train track system; mechanism of derailment and energy increment criterion for derailment evaluation; calculation of the entire derailment course of train. This theory is used to calculate a case of freight train derailment, which corresponds to an actually occurring accident. Another derailment test, in which the train is judged not to be derailed, is calculated and the maximum vibration response is well correspond to the test results. And the effectiveness and practicability of the theory are proved by the two calculated cases. 展开更多
关键词 DERAILMENT RANDOM energy analysis theory TRAIN TRANSVERSE VIBRATION
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Analysis of the Red and the Black via Aristotle's Catharsis Theory
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作者 杨文星 《科技信息》 2010年第10期158-159,共2页
The Red and the Black,authored by French writer Stendhal,depicts the rugged short life of Julian and vividly presents to readers a picture of social life under the reign of Charles X. Being a masterpiece of critical r... The Red and the Black,authored by French writer Stendhal,depicts the rugged short life of Julian and vividly presents to readers a picture of social life under the reign of Charles X. Being a masterpiece of critical realism,its description of figures and arrangement of plot are intimately bound up with ancient Greek spirit of tragedy. The present paper aims to analysis the unity of plot as well as characters of figures in The Red and the Black via Aristotle's tragedy theory of catharsis,and to expound the tragic effect of this novel. 展开更多
关键词 英语学习 英语习语 英汉翻译 商务英语
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Risk Analysis on Groundwater Resources Carrying Capacity Based on Blind Number Theory 被引量:5
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作者 ZHANG Ji1,2,YU Sujun31. Key Laboratory of Mountain Hazards and Surface Process,Chinese Academy of Sciences/Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610041,Sichuan,China 2. Graduate University of the Chinese Academy of Sciences,Beijing 100049,China 3. School of Environmental Science and Engineering,Southwest Jiaotong University,Chengdu 610041,Sichuan,China 《Wuhan University Journal of Natural Sciences》 CAS 2007年第4期669-676,共8页
Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy the... Blind numbers of evaluation indices about groundwater resources carrying capacity are defined from the concomitancy of randomness, fuzziness, grey property and unascertainment of groundwater system. Based on fuzzy theory, a comprehensive evaluation model on groundwater resources carrying capacity is constructed with blind information. Then a risk assessment model of surcharge about groundwater resources carrying capacity is established on blind reliability theory. The probable value "*" matrix of fuzzy membership degree about carrying capacity corresponding to each judgment level can be obtained with the aid of blind algorithm as well as the subjective reliability "×" matrix. And then a graph of "groundwater carrying capacity v.s. accumulative reliability" can be gained Based on the graph, fuzzy membership degree of groundwater resources carrying capacity to each judgment level under different risk probability can be got. Thus, a comparatively reasonable judgment to groundwater resources carrying capacity might be obtained, with comprehensive analysis to the state of society, economy technology and ecology. 展开更多
关键词 blind number theory groundwater resources carrying capacity evaluation risk analysis
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Use of digital image analysis combined with fractal theory to determine particle morphology and surface texture of quartz sands 被引量:4
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作者 Georgia S.Araujo Kátia V.Bicalho Fernando A.Tristao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2017年第6期1131-1139,共9页
The particle morphology and surface texture play a major role in influencing mechanical and hydraulic behaviors of sandy soils. This paper presents the use of digital image analysis combined with fractal theory as a t... The particle morphology and surface texture play a major role in influencing mechanical and hydraulic behaviors of sandy soils. This paper presents the use of digital image analysis combined with fractal theory as a tool to quantify the particle morphology and surface texture of two types of quartz sands widely used in the region of Vitória, Espírito Santo, southeast of Brazil. The two investigated sands are sampled from different locations. The purpose of this paper is to present a simple, straightforward,reliable and reproducible methodology that can identify representative sandy soil texture parameters.The test results of the soil samples of the two sands separated by sieving into six size fractions are presented and discussed. The main advantages of the adopted methodology are its simplicity, reliability of the results, and relatively low cost. The results show that sands from the coastal spit(BS) have a greater degree of roundness and a smoother surface texture than river sands(RS). The values obtained in the test are statistically analyzed, and again it is confirmed that the BS sand has a slightly greater degree of sphericity than that of the RS sand. Moreover, the RS sand with rough surface texture has larger specific surface area values than the similar BS sand, which agree with the obtained roughness fractal dimensions. The consistent experimental results demonstrate that image analysis combined with fractal theory is an accurate and efficient method to quantify the differences in particle morphology and surface texture of quartz sands. 展开更多
关键词 Quartz sands Particle morphology and surface texture Image analysis Fractal theory
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Stability analysis of underground surrounding rock mass based on block theory 被引量:8
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作者 LIN Jian-yun ZUO Yu-jun +4 位作者 WANG Jian ZHENG Lu-jing CHEN Bin SUN Wen-ji-bin LIU Hao 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第10期3040-3052,共13页
Evaluation of the performance of existing support in underground tunnels is of great importance for production and interests.Based on field investigation,the shape and number of joints and fractures were investigated ... Evaluation of the performance of existing support in underground tunnels is of great importance for production and interests.Based on field investigation,the shape and number of joints and fractures were investigated in the mining area.Then,the stability of each structural blocks is analyzed by 3D wedge stability analysis software(Unwedge).Moreover,a new analysis method based on critical block theory is applied to analyze the stability of excavated laneways in continuous and discontinuous rock and monitor the stress changes in a fractured tunnel rock mass.The test results indicate that the 3D wedge stability analysis software for underground excavation can evaluate deep tunnel support.Besides,there is no direct relation between the size of the block and the instability of the tunnel.The support method,on large and thick key blocks,needs to be improved.In a broken tunnel section,U-shaped steel support can effectively promote the stress state of the surrounding rock.By monitoring the surrounding rock,it is proven that the vibrating string anchor stress monitoring system is an efficient and real-time method for tunnel stability evaluation. 展开更多
关键词 block theory Unwedge analysis software stress monitoring system support evaluation
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Application of periodic orbit theory in chaos-based security analysis 被引量:3
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作者 龙敏 丘水生 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第8期2254-2258,共5页
Chaos-based encryption schemes have been studied extensively, while the security analysis methods for them are still problems to be resolved. Based on the periodic orbit theory, this paper proposes a novel security an... Chaos-based encryption schemes have been studied extensively, while the security analysis methods for them are still problems to be resolved. Based on the periodic orbit theory, this paper proposes a novel security analysis method. The periodic orbits theory indicates that the fundamental frequency of the spiraling orbits is the natural frequency of associated linearized system, which is decided by the parameters of the chaotic system. Thus, it is possible to recover the plaintext of secure communication systems based on chaotic shift keying by getting the average time on the spiraling orbits. Analysis and simulation results show that the security analysis method can break chaos shift keying secure communication systems, which use the parameters as keys. 展开更多
关键词 periodic orbit theory secure communication chaos-based security analysis
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Analysis on the Application of Schema Theory to Improve English Listening Teaching Effectiveness
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作者 黄莹 《海外英语》 2013年第3X期36-37,39,共3页
Based on the schema theory,the paper analyzes the psychological cognitive process of listening comprehension.Schema theory provides a good theoretical basis to improve the English listening teaching effectiveness.Prac... Based on the schema theory,the paper analyzes the psychological cognitive process of listening comprehension.Schema theory provides a good theoretical basis to improve the English listening teaching effectiveness.Practice shows that the schema theory application to guide teaching practice can achieve great progress in an English listening classroom. 展开更多
关键词 SCHEMA theory LISTENING COMPREHENSION COGNITIVE an
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Safe range analysis of clear distance of twin shallow tunnels based on limit analysis and reliability theory 被引量:8
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作者 ZHANG Biao WANG Xuan +2 位作者 ZHANG Jia-sheng ZHANG Jia-hua CHENG Hao 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期196-207,共12页
A method of analyzing the stability of twin shallow tunnels was presented using both limit analysis with nonlinear failure criterion and reliability theory.In the condition of nonlinear failure criterion,the critical ... A method of analyzing the stability of twin shallow tunnels was presented using both limit analysis with nonlinear failure criterion and reliability theory.In the condition of nonlinear failure criterion,the critical clear distancesof twin shallow tunnels were obtained by analyzing the change of surrounding pressure.A reliability model was established based on limit state equation,and the failure probability was solved by virtue of Monte Carlo method.Safety factor and corresponding clear distance of different safety levels were obtained by introducing a target reliability index.The scope of clear distance for different safety levels is described,which can be used as a supplement and improvement to the design codes of tunnels. 展开更多
关键词 twin shallow tunnels limit analysis nonlinear failure criterion reliability theory clear distance
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Size dependent free vibration analysis of functionally graded piezoelectric micro/nano shell based on modified couple stress theory with considering thickness stretching effect 被引量:5
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作者 Maryam Lori Dehsaraji Mohammad Arefi Abbas Loghman 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第1期119-134,共16页
Higher-order shear and normal deformation theory is used in this paper to account thickness stretching effect for free vibration analysis of the cylindrical micro/nano shell subjected to an applied voltage and uniform... Higher-order shear and normal deformation theory is used in this paper to account thickness stretching effect for free vibration analysis of the cylindrical micro/nano shell subjected to an applied voltage and uniform temperature rising.Size dependency is included in governing equations based on the modified couple stress theory.Hamilton’s principle is used to derive governing equations of the cylindrical micro/nano shell.Solution procedure is developed using Navier technique for simply-supported boundary conditions.The numerical results are presented to investigate the effect of significant parameters such as some dimensionless geometric parameters,material properties,applied voltages and temperature rising on the free vibration responses. 展开更多
关键词 Thickness stretching effect Shear and normal deformation theory Vibration analysis Length scale parameter Modified couple stress theory
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Design and dynamic analysis of a scissors hoop-rib truss deployable antenna mechanism
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作者 Bo Han Xiangkun Li +3 位作者 Jian Sun Yundou Xu Jiantao Yao Yongsheng Zhao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期399-413,共15页
As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general par... As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel mechanism.In this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the ULSM.Kinematic analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one DOF.Velocity and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation transformation.Based on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB software.In addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole mechanism.The mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas. 展开更多
关键词 Scissors mechanism Deployable antenna Screw theory Kinematic analysis Dynamic analysis
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Vibration and wave propagation analysis of twisted micro-beam using strain gradient theory 被引量:3
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作者 M.MOHAMMADIMEHR M.J.FARAHI S.ALIMIRZAEI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第10期1375-1392,共18页
In this research, vibration and wave propagation analysis of a twisted micro- beam on Pasternak foundation is investigated. The strain-displacement relations (kine-matic equations) are calculated by the displacement... In this research, vibration and wave propagation analysis of a twisted micro- beam on Pasternak foundation is investigated. The strain-displacement relations (kine-matic equations) are calculated by the displacement fields of the twisted micro-beam. The strain gradient theory (SGT) is used to implement the size dependent effect at micro-scale. Finally, using an energy method and Hamilton's principle, the governing equations of motion for the twisted micro-beam are derived. Natural frequencies and the wave prop- agation speed of the twisted micro-beam are calculated with an analytical method. Also, the natural frequency, the phase speed, the cut-off frequency, and the wave number of the twisted micro-beam are obtained by considering three material length scale parameters, the rate of twist angle, the thickness, the length of twisted micro-beam, and the elastic medium. The results of this work indicate that the phase speed in a twisted micro-beam increases with an increase in the rate of twist angle. Moreover, the wave number is in- versely related with the thickness of micro-beam. Meanwhile, it is directly related to the wave propagation frequency. Increasing the rate of twist angle causes the increase in the natural frequency especially with higher thickness. The effect of the twist angle rate on the group velocity is observed at a lower wave propagation frequency. 展开更多
关键词 vibration and wave propagation analysis twisted micro-beam strain gradient theory (SGT) rate of twist angle
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