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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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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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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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General Kinetostatic Modeling and Deformation Analysis of a Two-Module Rod-Driven Continuum Robot with Friction Considered 被引量:1
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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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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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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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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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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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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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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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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:3
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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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Failure Statistics Analysis Based on Bayesian Theory: A Study of FPSO Internal Turret Leakage 被引量:1
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作者 KANG Ji-chuan WANG Lang +2 位作者 LI Ming-xin SUN Li-ping JIN Peng 《China Ocean Engineering》 SCIE EI CSCD 2019年第1期14-25,共12页
The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure mode... The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure models are difficult to establish through traditional statistical methods. Hence, the calculation of the occurrence probability of small sample events is often met with great uncertainty. In this study, the Bayesian statistical method is implemented to analyze the oil and gas leakages of FPSO internal turret, which is a typical small sample risk but could lead to severe losses.According to the corresponding failure mechanism, two Bayesian statistical models using the Weibull distribution and logarithmic normal distribution as the population distribution are established, and the posterior distribution of the corresponding parameters is calculated. The optimal Bayesian statistical model is determined according to the Bayesian information criterion and Akaike criterion. On the basis of the determined optimal model, the corresponding reliability index is solved to provide basic data for the subsequent risk assessments of FPSO systems. 展开更多
关键词 risk analysis Bayesian theory FPSO INTERNAL TURRET system MARKOV chain Monte Carlo
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Mathematical concepts and their physical foundation in the nonstandard analysis theory of turbulence 被引量:1
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作者 吴峰 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第5期1186-1196,共11页
Main mathematical concepts and their physical foundation in the nonstandard analysis theory of turbulence are presented and discussed. The underlying fact is that there does not exist the absolute zero fluid-volume. T... Main mathematical concepts and their physical foundation in the nonstandard analysis theory of turbulence are presented and discussed. The underlying fact is that there does not exist the absolute zero fluid-volume. Therefore, the physical object corresponding to the absolute point is just the uniform fluid-particle. The fluid-particle, in general, corresponds to the monad. The uniform fluid-particle corresponds to the uniform monad, while the nonuniform fluid-particle to the nonuniform monad. There are two kinds of the differentiations, one is based on the absolute point, and the other based on the monad. The former is adopted in the Navier-Stokes equations, and the latter in the fundamental equations presented in this paper for the nonstandard analysis theory of turbulence. The continuity of fluid is elucidated by virtue of the concepts of the fluid-particle and fluid-particle at a lower level. Furthermore, the characters of the continuity in two cases, i.e. in the standard and nonstandard analyses, are presented in this paper. And the difference in discretization between the Navier-Stokes equations and the fundamental equations given herein is also pointed out. 展开更多
关键词 TURBULENCE MONAD fluid-particle at a lower level nonstandard analysis theory of turbulence
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Generalized Kinematics Analysis of Hybrid Mechanisms Based on Screw Theory and Lie Groups Lie Algebras 被引量:2
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作者 Peng Sun Yanbiao Li +3 位作者 Ke Chen Wentao Zhu Qi Zhong Bo Chen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第5期171-184,共14页
Advanced mathematical tools are used to conduct research on the kinematics analysis of hybrid mechanisms,and the generalized analysis method and concise kinematics transfer matrix are obtained.In this study,first,acco... Advanced mathematical tools are used to conduct research on the kinematics analysis of hybrid mechanisms,and the generalized analysis method and concise kinematics transfer matrix are obtained.In this study,first,according to the kinematics analysis of serial mechanisms,the basic principles of Lie groups and Lie algebras are briefly explained in dealing with the spatial switching and differential operations of screw vectors.Then,based on the standard ideas of Lie operations,the method for kinematics analysis of parallel mechanisms is derived,and Jacobian matrix and Hessian matrix are formulated recursively and in a closed form.Then,according to the mapping relationship between the parallel joints and corresponding equivalent series joints,a forward kinematics analysis method and two inverse kinematics analysis methods of hybrid mechanisms are examined.A case study is performed to verify the calculated matrices wherein a humanoid hybrid robotic arm with a parallel-series-parallel configuration is considered as an example.The results of a simulation experiment indicate that the obtained formulas are exact and the proposed method for kinematics analysis of hybrid mechanisms is practically feasible. 展开更多
关键词 Hybrid mechanism Screw theory Lie groups Lie algebras Kinematics analysis Humanoid robotic arm
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Size-dependent effect on biaxial and shear nonlinear buckling analysis of nonlocal isotropic and orthotropic micro-plate based on surface stress and modified couple stress theories using differential quadrature method 被引量:2
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作者 M.MOHAMMADIMEHR M.A.MOHAMMADIMEHR P.DASHTI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第4期529-554,共26页
The size-dependent effect on the biaxial and shear nonlinear buckling analysis of an isotropic and orthotropic micro-plate based on the surface stress, the modified couple stress theory (MCST), and the nonlocal elas... The size-dependent effect on the biaxial and shear nonlinear buckling analysis of an isotropic and orthotropic micro-plate based on the surface stress, the modified couple stress theory (MCST), and the nonlocal elasticity theories using the differential quadrature method (DQM) is presented. Main advantages of the MCST over the classical theory (CT) are the inclusion of the asymmetric couple stress tensor and the consideration of only one material length scale parameter. Based on the nonlinear von Karman assumption, the governing equations of equilibrium for the micro-classical plate consid- ering midplane displacements are derived based on the minimum principle of potential energy. Using the DQM, the biaxial and shear critical buckling loads of the micro-plate for various boundary conditions are obtained. Accuracy of the obtained results is validated by comparing the solutions with those reported in the literature. A parametric study is conducted to show the effects of the aspect ratio, the side-to-thickness ratio, Eringen's nonlocal parameter, the material length scale parameter, Young's modulus of the surface layer, the surface residual stress, the polymer matrix coefficients, and various boundary conditions on the dimensionless uniaxial, biaxial, and shear critical buckling loads. The results indicate that the critical buckling loads are strongly sensitive to Eringen's nonlocal parameter, the material length scale parameter, and the surface residual stress effects, while the effect of Young's modulus of the surface layer on the critical buckling load is negligible. Also, considering the size dependent effect causes the increase in the stiffness of the orthotropic micro-plate. The results show that the critical biaxial buckling load increases with an increase in G12/E2 and vice versa for E1/E2. It is shown that the nonlinear biaxial buckling ratio decreases as the aspect ratio increases and vice versa for the buckling amplitude. Because of the most lightweight micro-composite materials with high strength/weight and stiffness/weight ratios, it is anticipated that the results of the present work are useful in experimental characterization of the mechanical properties of micro-composite plates in the aircraft industry and other engineering applications. 展开更多
关键词 biaxial and shear nonlinear buckling analysis nonlocal isotropic and orthotropic micro-plate modified couple stress theory (MCST) surface stress effect differential quadrature method (DQM)
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Nonlinearity analysis of piezoelectric micromachined ultrasonic transducers based on couple stress theory 被引量:4
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作者 Xin Kang Fu-Jun Yang Xiao-Yuan He 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2012年第1期104-111,共8页
This paper studies the static deformation behavior of a piezoelectric micromachined ultrasonic transducer (PMUT) actuated by a strong external electric field. The transducer membrane consists of a piezoelectric laye... This paper studies the static deformation behavior of a piezoelectric micromachined ultrasonic transducer (PMUT) actuated by a strong external electric field. The transducer membrane consists of a piezoelectric layer, a passive layer and two electrode layers. The nonlinearities of the piezoelectric layer caused by electrostriction under a strong electric field are analyzed. Because the thickness of the transducer membrane is on the microscale, the size dependence of the deformation behavior is evaluated using the couple stress theory. The results show that the optimal ratio of the top electrode diameter and the membrane diameter is around 0.674. It is also found that this optimal value does not depend on any other parameters if the thicknesses of the two electrodes are negligible compared with those of the piezo- electric and passive layers. In addition, the nonlinearities of the piezoelectric layer will become stronger along with the increase of the electric field, which means that softening of the membrane stiffness occurs when a strong external electric field is applied. Meanwhile, the optimal thickness ratio for the passive layer and the piezoelectric layer is not equal to 1.0 which is usually adopted by previous researchers. Because there exists size dependence of membrane deforma-tion, the optimal value of this thickness ratio needs to be greater than 1.0 on the microscale. 展开更多
关键词 Piezoelectric micromachined ultrasonic trans- ducer (PMUT) Couple stress theory Static deformation - Nonlinearity analysis
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Finite element analysis of functionally graded sandwich plates with porosity via a new hyperbolic shear deformation theory 被引量:1
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作者 Pham Van Vinh Le Quang Huy 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第3期490-508,共19页
This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates wi... This study focusses on establishing the finite element model based on a new hyperbolic sheareformation theory to investigate the static bending,free vibration,and buckling of the functionally graded sandwich plates with porosity.The novel sandwich plate consists of one homogenous ceramic core and two different functionally graded face sheets which can be widely applied in many fields of engineering and defence technology.The discrete governing equations of motion are carried out via Hamilton’s principle and finite element method.The computation program is coded in MATLAB software and used to study the mechanical behavior of the functionally graded sandwich plate with porosity.The present finite element algorithm can be employed to study the plates with arbitrary shape and boundary conditions.The obtained results are compared with available results in the literature to confirm the reliability of the present algorithm.Also,a comprehensive investigation of the effects of several parameters on the bending,free vibration,and buckling response of functionally graded sandwich plates is presented.The numerical results shows that the distribution of porosity plays significant role on the mechanical behavior of the functionally graded sandwich plates。 展开更多
关键词 Functionally graded sandwich plates Porous plates Hyperbolic shear deformation theory Bending analysis Free vibration analysis Buckling analysis
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