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Rotordynamics analysis of a double-helical gear transmission system

MECCANICA 2016年第1期51卷 251-268页

作者： Chen, Siyu Tang, Jinyuan Li, Yuanping Hu, Zehua Cent S Univ State Key Lab High Performance Complex Mfg Changsha 410083 Hunan Peoples R China Jinan Univ Key Lab Disaster Forecast & Control Engn Minist Educ Peoples Republ China Guangzhou Guangdong Peoples R China

The rotordynamics of a double-helical gear transmission system is investigated. The equation of motion of the system with bearing and gyroscopic effect is derived by using the finite element method, in which Timoshenko beam finite element is used to represent the shaft, a rigid mass for the gear. Natural frequencies, mode shapes and Campbell diagrams are illustrated to indicate the effects of gear input speed and time varying mesh stiffness. Besides, effects of mesh stiffness on the critical speed of the gear transmission system are analyzed. The numerical results show that the axial force has significant influence on the natural frequency and the mode shape of the double-helical gear transmission system, for which the mix whirling motion dominates the natural characteristics. There are two higher critical speed curves which increase with the mesh stiffness, but one of them is related to the gyroscopic effect.

关键词： Double-helical gear Natural frequency Whirling Campbell diagram

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A consistency elasto-viscoplastic damage model for progressive failure analysis of composite laminates subjected to various strain rate loadings

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COMPOSITE STRUCTURES 2016年 148卷 224-235页

作者： Chen, Jing-Fen Morozov, Evgeny V. Jinan Univ Key Lab Disaster Forecast & Control Engn Dept Mech & Civil Engn Guangzhou Guangdong Peoples R China Univ New S Wales Sch Engn & Informat Technol Canberra ACT Australia

This paper is concerned with the development and validation of a consistency elasto-viscoplastic damage model that accounts for the strain rate-dependent plastic response and the progressive post-failure behaviour of composite materials. The model proposed is suitable for progressive failure analysis of composite materials and structures subjected to loadings at various strain rates. A strain rate-dependent yield criterion is adopted;whereas the standard Kuhn-Tucker conditions for plastic loading and unloading remain valid. Also, the plastic consistency condition for strain rate-dependent material is satisfied. The relevant strain-driven implicit numerical integration procedure for the proposed material model is developed. A tangent stiffness operator including the strain rate-dependent effects and consistent with the integration procedure developed is derived to ensure the quadratic convergence rate pertaining to the Newton-Raphson method in a finite element analysis. The implicit integration algorithm is implemented in the finite element code Abaqus through the user-defined material subroutine UMAT. The validation of the proposed model is performed on S2/8552 glass/epoxy off-axis block composite specimens subjected to compression at various strain rates. It is shown that the strain rate-dependent response of composite materials is well captured and the predicted results agree well with the experimental data reported in the literature. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Strain rate effects Strain rate-dependent yield criterion Progressive failure analysis Composite materials Return mapping algorithm

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A study on the stretch tensor of the beam end in a curved girder bridge caused by environmental temperature change 4th

A study on the stretch tensor of the beam end in a curved gi...

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4th International Conference on Civil, Architectural and Hydraulic engineering, ICCAHE 2015

作者： Liu, Jie-Shan Gao, Jing-Hong College of Science and Engineering Jinan University Guangzhou China Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of China Guangzhou China

ISBN: (纸本)9781138029163

With day turning to night and summer to winter, the girder in the bridge would be lengthened or shortened. This is a normal phenomenon in every object. However, the curved girder bridge has a dissymmetric structure, supported shearing force, bending moment and torsion in the same node, which would stretch in an abnormal way when the temperature is changed. In this paper, using Midas Civil app after the theoretical analysis of thermodynamics, the displacement of the beam end is simulated in this finite element analysis software with the altering radius of the road centerline. By comparing these data of displacement with central angle in the equal radius of the girder, which work at the same temperature condition, the result shows that the connection between the displacement and central angle becomes approximate when considering in a small angle at the center. In addition, it would be a useful reference when installing the expansion joint. © 2016 Taylor & Francis Group, London.

关键词： Finite element method

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The research on the internal force effect of different vertical curves on a curved box girder bridge 4th

The research on the internal force effect of different verti...

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4th International Conference on Civil, Architectural and Hydraulic engineering, ICCAHE 2015

作者： Liao, Yu-Xiao Gao, Jing-Hong Department of Mechanics and Civil Engineering Jinan University Guangzhou China Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of China Guangzhou China

ISBN: (纸本)9781138029163

Using the stimulated structure MIDAS Civil to conduct the calculation with REM modeling, this paper analyzes the internal force of the curved girder bridge whose radius of curvature is R = 200 m. Under the condition of the unaltered span and radius of curvature, this paper investigates the effect of the internal force variation of the continuous curved box girder bridge that is influenced by permanent load and moving load with different vertical curves. © 2016 Taylor & Francis Group, London.

关键词： Box girder bridges

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Research on gas diffusion model and experimental diffusion characteristic of cylindrical coal

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Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology 2017年第5期46卷 1033-1040页

作者： Li, Zhiqiang Cheng, Qiang Liu, Yanwei Duan, Zhengpeng Song, Dangyu State Key Laboratory of Coal mine Disaster Dynamics and Control Chongqing University Chongqing400030 China Henan Polytechnic University JiaozuoHenan454000 China MOE Engineering Center of Mine Disaster Prevention and Rescue Henan Polytechnic University JiaozuoHenan454000 China Henan Provincial Key Lab of Gas Geology and Control-Cultivation Base of Provincial and Ministry Joint State Key Henan Polytechnic University JiaozuoHenan454000 China

Under various temperatures and pressures, the gas diffusion experiments were carried out with Φ50 mm×100 mm standard cylindrical coal samples. At the same time, a gas diffusion experiment was carried out by use of the particles of the same coal as comparative experiment. To describe the gas diffusion in cylindrical coal samples, the cylindrical diffusion model was established and the analytical solution of diffusion rate was derived. The results show that the gas diffusion in cylindrical raw coal is slower than that in coal particles. And the cumulative diffusion quantity and diffusivity in cylindrical raw coal is far less than those in coal particles under the same time. The diffusion coefficient of cylindrical raw coal is 11.72 times as much as that of coal particles. This is because that the cylindrical row coal contains a larger pore and fissure diamaters. But the effective diffusion coefficient of cylindrical raw coal is 1.82% of which in coal particles. That results from the extension of the diffusion path and the increase of the tortuosity. These lead the cylindrical coal core to contain a smaller capacity of release gas. © 2017, Editorial Board of Journal of CUMT. All right reserved.

关键词： Coal

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A novel PSO-based algorithm for structural damage detection using Bayesian multi-sample objective function

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STRUCTURAL engineering AND MECHANICS 2017年第6期63卷 825-835页

作者： Chen, Ze-peng Yu, Ling Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China China Three Gorges Univ Coll Civil Engn & Architecture Yichang 443002 Peoples R China

Significant improvements to methodologies on structural damage detection (SDD) have emerged in recent years. However, many methods are related to inversion computation which is prone to be ill-posed or ill-conditioning, leading to low-computing efficiency or inaccurate results. To explore a more accurate solution with satisfactory efficiency, a PSO-INM algorithm, combining particle swarm optimization (PSO) algorithm and an improved Nelder-Mead method (INM), is proposed to solve multi-sample objective function defined based on Bayesian inference in this study. The PSO-based algorithm, as a heuristic algorithm, is reliable to explore solution to SDD problem converted into a constrained optimization problem in mathematics. And the multi-sample objective function provides a stable pattern under different level of noise. Advantages of multi-sample objective function and its superior over traditional objective function are studied. Numerical simulation results of a two-storey frame structure show that the proposed method is sensitive to multi-damage cases. For further confirming accuracy of the proposed method, the ASCE 4-storey benchmark frame structure subjected to single and multiple damage cases is employed. Different kinds of modal identification methods are utilized to extract structural modal data from noise-contaminating acceleration responses. The illustrated results show that the proposed method is efficient to exact locations and extents of induced damages in structures.

关键词： structural damage detection PSO-INM multi-sample objective function benchmark model

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Thermal-Structural Coupling Analysis of PCBA System

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IOP Conference Series: Materials Science and engineering 2018年第2期452卷

作者： Wei Su Junhua Zhu Renhuai Liu Zhiyuan He Scienceand Technology on Reliability Physics and Application Technology of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou China MOE Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou China Department of Mechanics and Civil Engineering Jinan University Guangzhou China

In this paper, the thermal and structural analysis of the PCBA system is provided by using the 3-D ANSYS package. The results of thermal and structural analysis for complex and simple model are compared. The paper also describes the deformation analysis of the PCBA system components, and the weak components sensitive to thermal stress are determined though thermal-structual analysis. The results of thermal analysis are helpful to the optimizing overall arrangement design of PCBA system.

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Multi-Objective Topology Optimization of a Compliant Parallel Planar Mechanism under Combined Load Cases and Constraints

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MICROMACHINES 2017年第9期8卷 279-279页

作者： Wang, Gao Zhu, Dachang Liu, Ning Zhao, Wei Jinan Univ Sch Informat Sci & Technol Guangzhou 510632 Guangdong Peoples R China Guangzhou Univ Sch Mech & Elect Engn Guangzhou 510006 Guangdong Peoples R China Jinan Univ Minist Educ China Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

This paper focuses on a new type of configuration design of a compliant parallel mechanism (CPM) planar continuum structure and its characteristic analysis of vibration-inherent frequency for planar motion, which can suppress the impact of random vibration in ultra-precision positioning and manufacturing equipment and improve the inherent frequency response of the mechanism. Firstly, a vector-mapping isomorphism between the fully CPM and conventional isomorphic parallel mechanism was constructed with a kinematic differential Jacobian matrix. Then, the mathematical model of topology optimization was put forward considering the compromise programming on the static stiffness and mean vibration-inherent frequency of the mechanism as the design variable and the minimization of compliance as the objective function. A constraint of volume fraction was considered and multi-objective micro displacement mechanism topology optimization based on a prismatic-revolute-revolute (3-PRR) planar nano-positioning continuum structure was performed using the solid isotropic material with penalization (SIMP) technique, which combines the criteria of the optimization algorithm and the vector isomorphic mapping method. Multi-objective topology optimization of the continuum structure micro displacement mechanism was investigated and presented by optimizations with different initial rejection rates. The simulation results show that the stiffness and vibration suppression performance of the continuum structure were improved, whereas the positioning of differential kinematics characteristics of the 3-PRR micro displacement planar fully CPM and isomorphic prototype mechanism retain the same. The modal analysis also provides a rational configuration for the micro displacement mechanism dimensional design and its optimal modal parameters. The crossover oscillation in frequency response of the continuum structure was reduced and quickly converged in the optimization iterations. The performance of

关键词： multi-objective topological optimization differential vector isomorphic mapping 3-PRR planar micro displacement SIMP

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Research on the performance-based parameter of horizontal visor of certain wall relative to the sun zenith angle

International Journal of Multimedia and Ubiquitous Engineeri...

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International Journal of Multimedia and Ubiquitous engineering 2016年第4期11卷 267-276页

作者： Gao, Jian Tang, Jian Key Lab of Disaster Forecast and Control in Engineering Ministry of Education of the People’s Republic of China Jinan University China

The horizontal shading is one part of the buildings, outside shading systems. Relative sun elevation angle to the wall, and relative sun azimuthal angle to the wall γ are introduced. The optimum width for the southern shading of local buildings can be calculated according to the law of solar altitude change over time. In this research, relative sun elevation angle to the wallis key for design parameters determination of horizontal shading component. The present study optimized the design of the horizontal shading on the basis of the traditional design. The new design of the visor could still shade the exceeding sunlight in summer, but at the same time allow enough sunshine in winter. This design is environmental-friendly, energy and material-saving. © 2016 SERSC.

关键词： Walls (structural partitions)

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Periodic solution and bifurcation of a suspension vibration system by incremental harmonic balance and continuation method

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NONLINEAR DYNAMICS 2016年第1-2期83卷 941-950页

作者： Li Yuanping Chen Siyu Jinan Univ Minist Educ Peoples Republ China Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ Dept Mech & Civil Engn Guangzhou 510632 Guangdong Peoples R China Cent S Univ State Key Lab High Performance Complex Mfg Changsha 410083 Hunan Peoples R China

A compressed air generator hang under vehicle is simplified as a suspension mass connected to a vertical spring and two horizontal springs. It is configured generally as a geometrical negative stiffness to reduce dynamic stiffness. The periodic motion, chaotic motion and bifurcation of the compressed air generator model are investigated using the incremental harmonic balance method in combination with arc length continuation technique. The stability and bifurcation route are also distinguished with Floquet theory. The system exhibits a period doubling bifurcation route to chaos in different regions of excitation frequency. The stiffness ratio of the vertical spring and the horizontal spring has a significant influence on the dynamic response. When the vertical stiffness is close to the stiffness at horizontal direction, resonance occurs with the emergence of the chaotic motion. The dynamic response of the vibration system can be improved by reducing the stiffness in the horizontal direction to increase the stiffness ratio.

关键词： Nonlinear vibration Suspension Bifurcation Continuation Stability

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