Dynamic Characteristics Study with Multidegree-of-Freedom Coupling in TBM Cutterhead System Based on Complex Factors

A multidegree-of-freedom coupling dynamic model, which contains a joint cutterhead, an inner ring gear, a support shield body, and pinions, is established, considering the external stochastic excitations, time-varying meshing stiffness, transmission errors, clearance, and so forth. Based on the parameters of an actual project and the strong impact of external excitations, the modal properties and dynamic responses are analyzed, and the cutterhead joint surface loads are obtained and treated by rain flow count. Numerical results indicate that the low natural frequencies are 57 Hz and 61 Hz, and natural vibration modes are pinions-motors rotational mode and translational-overturning coupled mode of cutterhead with inner ring gear correspondingly. Besides, the axial and radial amplitude of dynamic responses are 0.55 mm and 0.25 mm, respectively. The frequencies of radial, torsional, and overturning vibrations are predominantly concentrated in 112 Hz and 120 Hz, which indicates that the vibration responses of cutterhead are mainly affected by the external excitations. Finally, as the rain-flow counting results have shown, the standard deviation of the cutterhead joint surface loads in each direction increases by 12–15 times, compared with that of the external excitations; therefore inertia effect should be considered in cutterhead design. The proposed research lays a foundation for dynamic performance optimization and fatigue crack growth life assessment of cutterhead structure.

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Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.3822 ◽

2011 ◽

Vol 250-253 ◽

pp. 3822-3826 ◽

Cited By ~ 1

Author(s):

Xian Mai Chen ◽

Xia Xin Tao ◽

Gao Hang Cui ◽

Fu Tong Wang

Keyword(s):

Dynamic Performance ◽

Dynamic Responses ◽

Wave Band ◽

Wheel Load ◽

Railway Line ◽

Acceleration Rate ◽

Time Histories ◽

Railway System ◽

Dynamic Performances ◽

Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

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Structure Sensitivity Analysis and Dynamic Performance Optimization of Marine Gearbox

Volume 10: 2017 ASME International Power Transmission and Gearing Conference ◽

10.1115/detc2017-67072 ◽

2017 ◽

Author(s):

Tengjiao Lin ◽

Daokun Xie ◽

Ziran Tan ◽

Bo Liu

Keyword(s):

Sensitivity Analysis ◽

Performance Optimization ◽

Optimization Design ◽

Dynamic Performance ◽

Structure Sensitivity ◽

Superposition Method ◽

Structure Parameters ◽

Analysis Model ◽

Vibration Acceleration ◽

Response Optimization

The aim of this paper is to investigate the influence of structure parameters on the vibration characteristics and improve the dynamic performance of marine gearbox. A finite element model was established to solve the dynamic response by using modal superposition method. Based on the theory of multi-objective optimization design, the structure sensitivity analysis model of marine gearbox was established, which takes the structure parameters of the housing as design variables. The modal and response sensitivity was obtained by using the optimal gradient method. According to the results of sensitivity analysis, a modal and response optimization model of marine gearbox was established. The objective was to avoid natural frequencies from the excitation frequencies and minimize the root mean square of vibration acceleration of the evaluating points on the surface of housing. Then the modal optimization and response optimization of gearbox were carried out by using zero-order and first-order optimization method. The results indicate that the dynamic optimization of the gearbox can be achieved. After optimization, the amplitude of vibration acceleration of the evaluating points on the housing surface has been reduced and the resonance of marine gearbox can be avoided.

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Dynamic Performance Optimization Research of Impeller-Baffle Compound Structure Under Water

2021 IEEE 12th International Conference on Mechanical and Intelligent Manufacturing Technologies (ICMIMT) ◽

10.1109/icmimt52186.2021.9476180 ◽

2021 ◽

Author(s):

Xianghua Bai ◽

Chunlin Chen ◽

Jiangang Lv ◽

Fei Gao ◽

Qijin Zhao

Keyword(s):

Performance Optimization ◽

Dynamic Performance ◽

Compound Structure

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Dynamic performance optimization of an arctic semi-submersible production system

Ocean Engineering ◽

10.1016/j.oceaneng.2021.110353 ◽

2022 ◽

Vol 244 ◽

pp. 110353

Author(s):

Aobo Zhang ◽

Zhenju Chuang ◽

Shewen Liu ◽

Li Zhou ◽

Yan Qu ◽

...

Keyword(s):

Performance Optimization ◽

Production System ◽

Dynamic Performance

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Dynamic Study of a Rooftop Vertical Axis Wind Turbine Tower Based on an Automated Vibration Data Processing Algorithm

Energies ◽

10.3390/en11113135 ◽

2018 ◽

Vol 11 (11) ◽

pp. 3135 ◽

Cited By ~ 5

Author(s):

Ying Wang ◽

Wensheng Lu ◽

Kaoshan Dai ◽

Miaomiao Yuan ◽

Shen-En Chen

Keyword(s):

Wind Turbine ◽

Vertical Axis ◽

Dynamic Responses ◽

Ambient Vibration ◽

Structural Vibration ◽

Vertical Axis Wind Turbine ◽

Mode Identification ◽

Stochastic Subspace Identification ◽

Vibration Data ◽

Vibration Responses

When constructed on tall building rooftops, the vertical axis wind turbine (VAWT) has the potential of power generation in highly urbanized areas. In this paper, the ambient dynamic responses of a rooftop VAWT were investigated. The dynamic analysis was based on ambient measurements of the structural vibration of the VAWT (including the supporting structure), which resides on the top of a 24-story building. To help process the ambient vibration data, an automated algorithm based on stochastic subspace identification (SSI) with a fast clustering procedure was developed. The algorithm was applied to the vibration data for mode identification, and the results indicate interesting modal responses that may be affected by the building vibration, which have significant implications for the condition monitoring strategy for the VAWT. The environmental effects on the ambient vibration data were also investigated. It was found that the blade rotation speed contributes the most to the vibration responses.

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Dynamic optimization method with applications for machine tools based on approximation model

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406217711728 ◽

2017 ◽

Vol 232 (11) ◽

pp. 2009-2022 ◽

Cited By ~ 3

Author(s):

TJ Li ◽

XH Ding ◽

K Cheng ◽

T Wu

Keyword(s):

Machine Tool ◽

Performance Optimization ◽

Machine Tools ◽

Optimization Design ◽

Natural Frequencies ◽

Dynamic Performance ◽

Machining Process ◽

Machining Accuracy ◽

Approximation Model ◽

Dynamic Behaviors

Natural frequencies and modal shapes of machine tools have position-dependent characteristics owing to their dynamic behaviors changing with the positions of moving parts. It is time-consuming and difficult to evaluate the dynamic behaviors of machine tools and their machining accuracy at different positions. In this paper, a Kriging approximation model coupled with finite element method is proposed to substitute the dynamic equations for obtaining the position-dependent natural frequencies of a machine tool, as well as relative positions between the tool and the workpiece during the machining process. Based on the proposed method, dynamic performance optimization design of the machine tool is conducted under the condition of minimum relative positions. Three case studies are illustrated to demonstrate the implementation of the proposed method.

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Dynamic Performance Optimization of Electromagnetic Levitation System Considering Sensor Position

IEEE Access ◽

10.1109/access.2020.2972341 ◽

2020 ◽

Vol 8 ◽

pp. 29446-29455 ◽

Cited By ~ 1

Author(s):

Yajian Li ◽

Danfeng Zhou ◽

Peng Cui ◽

Peichang Yu ◽

Qiang Chen ◽

...

Keyword(s):

Performance Optimization ◽

Dynamic Performance ◽

Electromagnetic Levitation ◽

Sensor Position ◽

Levitation System

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Quasi-Static Characteristics and Vibration Responses Analysis of Helical Geared Rotor System with Random Cumulative Pitch Deviations

Applied Sciences ◽

10.3390/app10124403 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4403

Author(s):

Bing Yuan ◽

Geng Liu ◽

Lan Liu

Keyword(s):

Degrees Of Freedom ◽

Transmission Error ◽

Rotor System ◽

Dynamic Responses ◽

Contact Ratio ◽

Tooth Contact Analysis ◽

Long Period ◽

Light Load ◽

Vibration Responses ◽

Loaded Tooth Contact Analysis

As one of the long period gear errors, the effects of random cumulative pitch deviations on mesh excitations and vibration responses of a helical geared rotor system (HGRS) are investigated. The long-period mesh stiffness (LPMS), static transmission error (STE), as well as composite mesh error (CMS), and load distributions of helical gears are calculated using an enhanced loaded tooth contact analysis (LTCA) model. A dynamic model with multi degrees of freedom (DOF) is employed to predict the vibration responses of HGRS. Mesh excitations and vibration responses analysis of unmodified HGRS are conducted in consideration of random cumulative pitch deviations. The results indicate that random cumulative pitch deviations have significant effects on mesh excitations and vibration responses of HGRS. The curve shapes of STE and CMS become irregular when the random characteristic of cumulative pitch deviations is considered, and the appearance of partial contact loss in some mesh cycles leads to decreased LPMS when load torque is relatively low. Vibration modulation phenomenon can be observed in dynamic responses of HGRS. In relatively light load conditions, the amplitudes of sideband frequencies become larger than that of mesh frequency and its harmonics (MFIHs) because of relatively high contact ratio. The influences of random cumulative pitch deviations on the vibration responses of modified HGRS are also discussed.

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Dynamic response mitigation of floating wind turbine platforms using tuned liquid column dampers

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0079 ◽

2015 ◽

Vol 373 (2035) ◽

pp. 20140079 ◽

Cited By ~ 23

Author(s):

V. Jaksic ◽

C. S. Wright ◽

J. Murphy ◽

C. Afeef ◽

S. F. Ali ◽

...

Keyword(s):

Renewable Energy ◽

Dynamic Performance ◽

Weather Conditions ◽

Liquid Column ◽

Dynamic Responses ◽

Floating Structure ◽

Energy Devices ◽

Wave Basin ◽

Liquid Column Dampers ◽

Output Only

In this paper, we experimentally study and compare the effects of three combinations of multiple tuned liquid column dampers (MTLCDs) on the dynamic performance of a model floating tension-leg platform (TLP) structure in a wave basin. The structural stability and safety of the floating structure during operation and maintenance is of concern for the performance of a renewable energy device that it might be supporting. The dynamic responses of the structure should thus be limited for these renewable energy devices to perform as intended. This issue is particularly important during the operation of a TLP in extreme weather conditions. Tuned liquid column dampers (TLCDs) can use the power of sloshing water to reduce surge motions of a floating TLP exposed to wind and waves. This paper demonstrates the potential of MTLCDs in reducing dynamic responses of a scaled TLP model through an experimental study. The potential of using output-only statistical markers for monitoring changes in structural conditions is also investigated through the application of a delay vector variance (DVV) marker for different conditions of control for the experiments.

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