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Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 465-469 doi: 10.1007/s11465-010-0115-9

摘要: A single wheelset drive model and 2-DOFs torsional vibration model were established to investigate the self-excited torsional vibration of a locomotive driving system. The simulation results indicate that the self-excited torsional vibration occurs when the steady slip velocity is located at the descending slope of the adhesion coefficient curve. The principle of energy conservation was used to analyze the mechanism of the self-excited vibration. The factors affecting on the amplitude of the self-excited vibration are studied.

关键词: locomotive     driving system     self-excited torsional vibration     mechanism     influence factor    

Hole quality in longitudinal–torsional coupled ultrasonic vibration assisted drilling of carbon fiber

Guofeng MA, Renke KANG, Zhigang DONG, Sen YIN, Yan BAO, Dongming GUO

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 538-546 doi: 10.1007/s11465-020-0598-y

摘要: Carbon fiber reinforced plastic (CFRP) composites are extremely attractive in the manufacturing of structural and functional components in the aircraft manufacturing field due to their outstanding properties, such as good fatigue resistance, high specific stiffness/strength, and good shock absorption. However, because of their inherent anisotropy, low interlamination strength, and abrasive characteristics, CFRP composites are considered difficult-to-cut materials and are prone to generating serious hole defects, such as delamination, tearing, and burrs. The advanced longitudinal–torsional coupled ultrasonic vibration assisted drilling (LTC-UAD) method has a potential application for drilling CFRP composites. At present, LTC-UAD is mainly adopted for drilling metal materials and rarely for CFRP. Therefore, this study analyzes the kinematic characteristics and the influence of feed rate on the drilling performance of LTC-UAD. Experimental results indicate that LTC-UAD can reduce the thrust force by 39% compared to conventional drilling. Furthermore, LTC-UAD can decrease the delamination and burr factors and improve the surface quality of the hole wall. Thus, LTC-UAD is an applicable process method for drilling components made with CFRP composites.

关键词: longitudinal–torsional coupled     ultrasonically drilling     CFRP     thrust force     hole quality    

Control of wind-induced vibration of long-span bridges and tall buildings

GU Ming

《结构与土木工程前沿(英文)》 2007年 第1卷 第1期   页码 51-62 doi: 10.1007/s11709-007-0005-3

摘要: With the rapid increase in scales of structures, research on controlling wind-induced vibration of large-scale structures, such as long-span bridges and super-tall buildings, has been an issue of great concern. For wind-induced vibration of large-scale structures, vibration frequencies and damping modes vary with wind speed. Passive, semiactive, and active control strategies are developed to improve the wind-resistance performance of the structures in this paper. The multiple tuned mass damper (MTMD) system is applied to control vertical bending buffeting response. A new semiactive lever-type tuned mass damper (TMD) with an adjustable frequency is proposed to control vertical bending buffeting and torsional buffeting and flutter in the whole velocity range of bridge decks. A control strategy named sinusoidal reference strategy is developed for adaptive control of wind-induced vibration of super-tall buildings. Multiple degrees of freedom general building aeroelastic model with a square cross-section is tested in a wind tunnel. The results demonstrate that the proposed strategies can reduce vibration effectively, and can adapt to wind-induced vibration control of large-scale structures in the uncertain dynamic circumstance.

关键词: torsional buffeting     large-scale     semiactive     adjustable frequency     building aeroelastic    

Sensitivity analysis of torsional vibration behavior of the shafting of a turbo generator set to changes

XIE Danmei, ZHANG Hengliang, DONG Chuan, LIU Zhanhui, YANG Changzhu

《能源前沿(英文)》 2007年 第1卷 第4期   页码 483-486 doi: 10.1007/s11708-007-0072-4

摘要: Aiming at a 300 MW turbo-generator model, the sensitivity of natural torsional frequencies and modes of torsional vibration (TV) to the rotational inertia and stiffness of the turbo-generator were analyzed. Calculation results show

关键词: Calculation     MW turbo-generator     sensitivity     stiffness    

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 194-202 doi: 10.1007/s11709-015-0292-z

摘要: Considering the interactions between an embedded foundation and saturated soil, the torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic medium are analyzed in this paper. Both a rigid foundation and an elastic foundation are considered. Assuming both the side surface and the bottom surface of the foundation are perfectly bonded to soil, the reaction torques that the side soil and bottom soil acting on the foundation can be gained from basic dynamic equations of the poroelastic medium. According to the dynamic equilibrium equations of a foundation under harmonic torque, the torsional vibrations of an embedded cylindrical foundation are presented. Besides, the angular amplitude of the foundation, the equivalent stiffness and damping coefficients of the soil are expressed explicitly. Selected examples are presented to investigate the influence of relevant parameters on the torsional vibrations.

关键词: embedded foundation     saturated soil     rigid foundation     elastic foundation     torsional vibration    

Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

《机械工程前沿(英文)》 2020年 第15卷 第3期   页码 374-389 doi: 10.1007/s11465-019-0580-8

摘要: In the existing literature, most studies investigated the free vibrations of a rotating pre-twisted cantilever beam; however, few considered the effect of the elastic-support boundary and the quantification of modal coupling degree among different vibration directions. In addition, Coriolis, spin softening, and centrifugal stiffening effects are not fully included in the derived equations of motion of a rotating beam in most literature, especially the centrifugal stiffening effect in torsional direction. Considering these deficiencies, this study established a coupled flapwise–chordwise–axial–torsional dynamic model of a rotating double-tapered, pre-twisted, and inclined Timoshenko beam with elastic supports based on the semi-analytic method. Then, the proposed model was verified with experiments and ANSYS models using Beam188 and Shell181 elements. Finally, the effects of setting and pre-twisted angles on the degree of coupling among flapwise, chordwise, and torsional directions were quantified via modal strain energy ratios. Results showed that 1) the appearance of torsional vibration originates from the combined effect of flapwise–torsional and chordwise–torsional couplings dependent on the Coriolis effect, and that 2) the flapwise–chordwise coupling caused by the pure pre-twisted angle is stronger than that caused by the pure setting angle.

关键词: elastic-support boundary     pre-twisted beam     semi-analytic method     modal strain energy ratio     torsional vibration    

Flexural-torsional buckling behavior of aluminum alloy beams

Xiaonong GUO,Zhe XIONG,Zuyan SHEN

《结构与土木工程前沿(英文)》 2015年 第9卷 第2期   页码 163-175 doi: 10.1007/s11709-014-0272-8

摘要: This paper presents an investigation on the flexural-torsional buckling behavior of aluminum alloy beams (AAB). First, based on the tests of 14 aluminum alloy beams under concentrated loads, the failure pattern, load-deformation curves, bearing capacity and flexural-torsional buckling factor are studied. It is found that all the beam specimens collapsed in the flexural-torsional buckling with excessive deformation pattern. Moreover, the span, loading location and slenderness ratio influence the flexural-torsional buckling capacity of beams significantly. Secondly, besides the experiments, a finite element method (FEM) analysis on the flexural-torsional buckling behavior of AAB is also conducted. The main parameters in the FEM analysis are initial imperfection, material property, cross-section and loading scheme. According to the analytical results, it is indicated that the FEM is reasonable to capture mechanical behavior of AAB. Finally, on the basis of the experimental and analytical results, theoretical formulae to estimate the flexural-torsional buckling capacity of AAB are proposed, which could improve the application of present codes for AAB.

关键词: flexural-torsional buckling     aluminum alloy beams (AAB)     finite element method (FEM)     theoretical formula    

A novel structural modification to eliminate the early coupling between bending and torsional mode shapes

Nazim Abdul NARIMAN

《结构与土木工程前沿(英文)》 2017年 第11卷 第2期   页码 131-142 doi: 10.1007/s11709-016-0376-4

摘要: In this paper, a novel structural modification approach has been adopted to eliminate the early coupling between the bending and torsional mode shapes of vibrations for a cable stayed bridge model generated using ABAQUS software. Two lateral steel beams are added to the middle span of the structure. Frequency analysis is dedicated to obtain the natural frequencies of the first eight mode shapes of vibrations before and after the structural modification approach. Numerical simulations of wind excitations are conducted for the 3D model of the cable stayed bridge with duration of 30 s supporting on real data of a strong wind from the literature. Both vertical and torsional displacements are calculated at the mid span of the deck to analyze both the bending and the torsional stiffness of the system before and after the structural modification. The results of the frequency analysis after applying lateral steel beams declared a safer structure against vertical and torsional vibrations and rarely expected flutter wind speed. Furthermore, the coupling between the vertical and torsional mode shapes has been removed to larger natural frequencies magnitudes with a high factor of safety. The novel structural approach manifested great efficiency in increasing vertical and torsional stiffness of the structure.

关键词: aeroelastic instability     structural damping     flutter wind speed     bending stiffness     torsional stiffness    

An analytical method for calculating torsional constants for arbitrary complicated thin-walled cross-sections

DU Baisong, GE Yaojun, ZHOU Zheng

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 293-297 doi: 10.1007/s11709-007-0038-7

摘要: In this paper, an analytical method is proposed for calculating torsional constants for complicated thin-walled cross-sections with arbitrary closed or open rib stiffeners. This method uses the free torsional theory and the principle of virtual work to build governing equilibrium equations involving unknown shear flows and twisting rate. After changing the form of the equations and combining these two unknowns into one, torsional function, which is a function of shear flow, shear modulus, and twisting rate, is included in the governing equations as only one of the unknowns. All the torsional functions can be easily obtained from these homogeneous linear equations, and torsional constants can be easily obtained from the torsional functions. The advantage of this method is that we can easily and directly obtain torsional constants from the torsional functions, rather than the more sophisticated shear flow and twisting rate calculations. Finally, a complicated thin-walled cross-section is given as a valid numerical example to verify the analytical method, which is much more accurate and simpler than the traditional finite element method.

关键词: homogeneous     complicated thin-walled     numerical example     advantage     torsional function    

Lateral-torsional buckling capacity assessment of web opening steel girders by artificial neural networks

Yasser SHARIFI,Sajjad TOHIDI

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 167-177 doi: 10.1007/s11709-014-0236-z

摘要: Bridge girders exposed to aggressive environmental conditions are subject to time-variant changes in resistance. There is therefore a need for evaluation procedures that produce accurate predictions of the load-carrying capacity and reliability of bridge structures to allow rational decisions to be made about repair, rehabilitation and expected life-cycle costs. This study deals with the stability of damaged steel I-beams with web opening subjected to bending loads. A three-dimensional (3D) finite element (FE) model using ABAQUS for the elastic flexural torsional analysis of I-beams has been used to assess the effect of web opening on the lateral buckling moment capacity. Artificial neural network (ANN) approach has been also employed to derive empirical formulae for predicting the lateral-torsional buckling moment capacity of deteriorated steel I-beams with different sizes of rectangular web opening using obtained FE results. It is found out that the proposed formulae can accurately predict residual lateral buckling capacities of doubly-symmetric steel I-beams with rectangular web opening. Hence, the results of this study can be used for better prediction of buckling life of web opening of steel beams by practice engineers.

关键词: steel I-beams     lateral-torsional buckling     finite element (FE) method     artificial neural network (ANN) approach    

Proposing two new methods to decrease lateral-torsional buckling in reduced beam section connections

Samira EBRAHIMI; Nasrin BAKHSHAYESH EGHBALI; Mohammad Mehdi AHMADI

《结构与土木工程前沿(英文)》 2022年 第16卷 第12期   页码 1581-1598 doi: 10.1007/s11709-022-0886-1

摘要: Reduced web section (RWS) connections can prevent lateral-torsional buckling and web local buckling experienced by reduced beam section (RBS) connections. In RWS connections, removing a large portion of web can result in shear demand intolerance induced to plastic hinge region. The present study aims to resolve the problems of RBS and RWS connections by proposing two new connections: (1) RBS with stiffener (RBS-ST) and (2) RBS with reduced web (RW-RBS) connections. In the first connection (RBS-ST), a series of stiffeners is connected to the beam in the reduced flange region, while the second connection (RW-RBS) considers both a reduction in flanges and a reduction in web. Five beam-to-column joints with three different connections, including RBS, RBS-ST, and RW-RBS connections were considered and simulated in ABAQUS. According to the results, RBS-ST and RW-RBS connections can decrease or even eliminate lateral-torsional buckling and web local buckling in RBS connection. It is important to note that RW-RBS connection is more effective in long beams with smaller shear demands in the plastic hinge region. Moreover, results showed that RBS and RW-RBS connections experienced strength degradation at 4% to 5% drift, while no strength degradation was observed in RBS-ST connection until 8% drift.

关键词: RBS     RBS-ST     RW-RBS     lateral-torsional buckling     cyclic performance    

Vibration characteristics and machining performance of a novel perforated ultrasonic vibration platform

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0730-2

摘要: Ultrasonic vibration-assisted grinding (UVAG) is an advanced hybrid process for the precision machining of difficult-to-cut materials. The resonator is a critical part of the UVAG system. Its performance considerably influences the vibration amplitude and resonant frequency. In this work, a novel perforated ultrasonic vibration platform resonator was developed for UVAG. The holes were evenly arranged at the top and side surfaces of the vibration platform to improve the vibration characteristics. A modified apparent elasticity method (AEM) was proposed to reveal the influence of holes on the vibration mode. The performance of the vibration platform was evaluated by the vibration tests and UVAG experiments of particulate-reinforced titanium matrix composites. Results indicate that the reasonable distribution of holes helps improve the resonant frequency and vibration mode. The modified AEM, the finite element method, and the vibration tests show a high degree of consistency for developing the perforated ultrasonic vibration platform with a maximum frequency error of 3%. The employment of ultrasonic vibration reduces the grinding force by 36% at most, thereby decreasing the machined surface defects, such as voids, cracks, and burnout.

关键词: ultrasonic vibration-assisted grinding     perforated ultrasonic vibration platform     vibration characteristics     apparent elasticity method     grinding force     surface integrity    

Recent development of vibration utilization engineering

WEN Bangchun

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 1-9 doi: 10.1007/s11465-008-0017-2

摘要: The utilization of vibration and wave, which was developed during the latter half of the 20th century, is one of the most valueable technology applications and has been rapidly developing recently . Because the technique is closely associated with industry and agriculture, it can create huge social and economical benefits and provide excellent services for society. Thus, due to its necessity in industry and daily life, extensive research has been devoted to vibration utillization engineering. In this paper, vibration utilization is classified into linear or non-linear vibrations, waves, and electric-magnetic oscillations. Their phenomena, patterns, and applications in nature and society are introduced. Some research results about vibration utilization engineering are described.

关键词: utilization engineering     non-linear     vibration     vibration utillization     utillization engineering    

Application of python-based Abaqus preprocess and postprocess technique in analysis of gearbox vibration

Guilian YI, Yunkang SUI, Jiazheng DU

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 229-234 doi: 10.1007/s11465-011-0128-z

摘要:

To reduce vibration and noise, a damping layer and constraint layer are usually pasted on the inner surface of a gearbox thin shell, and their thicknesses are the main parameters in the vibration and noise reduction design. The normal acceleration of the point on the gearbox surface is the main index that can reflect the vibration and noise of that point, and the normal accelerations of different points can reflect the degree of the vibration and noise of the whole structure. The K-S function is adopted to process many points’ normal accelerations as the comprehensive index of the vibration characteristics of the whole structure, and the vibration acceleration level is adopted to measure the degree of the vibration and noise. Secondary development of the Abaqus preprocess and postprocess on the basis of the Python scripting programming automatically modifies the model parameters, submits the job, and restarts the analysis totally, which avoids the tedious work of returning to the Abaqus/CAE for modifying and resubmitting and improves the speed of the preprocess and postprocess and the computational efficiency.

关键词: Abaqus secondary development     Python language     vibration and noise reduction     K-S function     vibration acceleration level    

Similitude design for the vibration problems of plates and shells: A review

Yunpeng ZHU, You WANG, Zhong LUO, Qingkai HAN, Deyou WANG

《机械工程前沿(英文)》 2017年 第12卷 第2期   页码 253-264 doi: 10.1007/s11465-017-0418-1

摘要:

Similitude design plays a vital role in the analysis of vibration and shock problems encountered in large engineering equipment. Similitude design, including dimensional analysis and governing equation method, is founded on the dynamic similitude theory. This study reviews the application of similitude design methods in engineering practice and summarizes the major achievements of the dynamic similitude theory in structural vibration and shock problems in different fields, including marine structures, civil engineering structures, and large power equipment. This study also reviews the dynamic similitude design methods for thin-walled and composite material plates and shells, including the most recent work published by the authors. Structure sensitivity analysis is used to evaluate the scaling factors to attain accurate distorted scaling laws. Finally, this study discusses the existing problems and the potential of the dynamic similitude theory for the analysis of vibration and shock problems of structures.

关键词: review     dynamic     similitude     vibration     model test    

标题 作者 时间 类型 操作

Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

期刊论文

Hole quality in longitudinal–torsional coupled ultrasonic vibration assisted drilling of carbon fiber

Guofeng MA, Renke KANG, Zhigang DONG, Sen YIN, Yan BAO, Dongming GUO

期刊论文

Control of wind-induced vibration of long-span bridges and tall buildings

GU Ming

期刊论文

Sensitivity analysis of torsional vibration behavior of the shafting of a turbo generator set to changes

XIE Danmei, ZHANG Hengliang, DONG Chuan, LIU Zhanhui, YANG Changzhu

期刊论文

Torsional vibrations of a cylindrical foundation embedded in a saturated poroelastic half-space

Dazhi WU,Lu YU

期刊论文

Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

Jin ZENG, Chenguang ZHAO, Hui MA, Bangchun WEN

期刊论文

Flexural-torsional buckling behavior of aluminum alloy beams

Xiaonong GUO,Zhe XIONG,Zuyan SHEN

期刊论文

A novel structural modification to eliminate the early coupling between bending and torsional mode shapes

Nazim Abdul NARIMAN

期刊论文

An analytical method for calculating torsional constants for arbitrary complicated thin-walled cross-sections

DU Baisong, GE Yaojun, ZHOU Zheng

期刊论文

Lateral-torsional buckling capacity assessment of web opening steel girders by artificial neural networks

Yasser SHARIFI,Sajjad TOHIDI

期刊论文

Proposing two new methods to decrease lateral-torsional buckling in reduced beam section connections

Samira EBRAHIMI; Nasrin BAKHSHAYESH EGHBALI; Mohammad Mehdi AHMADI

期刊论文

Vibration characteristics and machining performance of a novel perforated ultrasonic vibration platform

期刊论文

Recent development of vibration utilization engineering

WEN Bangchun

期刊论文

Application of python-based Abaqus preprocess and postprocess technique in analysis of gearbox vibration

Guilian YI, Yunkang SUI, Jiazheng DU

期刊论文

Similitude design for the vibration problems of plates and shells: A review

Yunpeng ZHU, You WANG, Zhong LUO, Qingkai HAN, Deyou WANG

期刊论文