Spectrum Multiplication of Natural Frequency for Measuring Cable Tension by Vibration Frequency Method

2011 ◽  
Vol 9 (4) ◽  
pp. 1462-1466
Author(s):  
Lin Liu ◽  
Weimin Chen ◽  
Peng Zhang
Keyword(s):  
Natural Frequency ◽  
Vibration Frequency ◽  
Frequency Method ◽  
Cable Tension

Design and Experimental Investigations of a Vibration Based Wireless Measurement System for Bridge Cable Tension Monitoring

2014 ◽  
Vol 17 (11) ◽  
pp. 1657-1668 ◽  
Author(s):  
Yan Yu ◽  
Chunwei Zhang ◽  
Xinqun Zhu ◽  
Won Hee Kang ◽  
Xingquan Mao ◽  
...  
Keyword(s):  
Monitoring System ◽  
Measurement System ◽  
Vibration Frequency ◽  
Identification Algorithm ◽  
Frequency Method ◽  
Cable Tension ◽  
Wireless Monitoring ◽  
Cable Stayed Bridge ◽  
Wireless Measurement ◽  
Bridge Cable

Cables are important components of a cable-stayed bridge, and the cable tension is a crucial factor in determining the overall condition assessment of a cable-stayed bridge structure. Based on the vibration frequency method, a wireless monitoring system for bridge cable tension force monitoring has been investigated and experimentally validated through laboratory and field tests in this paper. The vibration frequency-based method for cable tension measurement, the design method of the wireless measurement system with embedded identification algorithm, the test procedures, and relevant results are discussed, respectively. The developed wireless monitoring system is verified by a bridge model test in the laboratory and full-scale bridge tests in the field. Field experimental results show that the relative error between this wireless monitoring system and the reference wired system values is within 0.5%. Therefore, the developed wireless measurement system can provide an estimation of cable tension with sufficient accuracy. Moreover, the developed system is highly integrated and convenient in terms of installation and dismantling, and it has potential applicability prospects in emergency for the quick detection of cable tension.

Field Measurement of Cable Tension Using Energy Method

2011 ◽  
Vol 230-232 ◽  
pp. 708-712
Author(s):  
Qi Lin Zhang ◽  
Da Lin Li ◽  
Ru Jin Ma
Keyword(s):  
Vibration Frequency ◽  
Energy Method ◽  
Vibration Mode ◽  
Tensile Force ◽  
Frequency Method ◽  
Cable Tension ◽  
Cable Structures ◽  
Simple Boundary ◽  
The Common ◽  
Energy Conservation Principle

For existing cable structures, vibration frequency method (VFM) seems to be the common way to determine the tensile force of the cables. However, the applicability of this method is limited by the specific conditions of cables. Only well tensioned slender cables with simple boundary conditions can be measured through VFM directly without causing much error. In this paper, the vibration mode of the cable is measured and then cable tension is calculated via energy conservation principle.

Cable Tension Measurement of Cable Stayed Bridge Based on Frequency Method

2013 ◽  
Vol 405-408 ◽  
pp. 1587-1592
Author(s):  
Zhi Hua Sun ◽  
Ping Yang
Keyword(s):  
Vibration Frequency ◽  
Indirect Method ◽  
Flexural Rigidity ◽  
Engineering Practice ◽  
Frequency Method ◽  
Cable Tension ◽  
String Vibration ◽  
Vibration Theory ◽  
Cable Stayed Bridge ◽  
Measured Frequency

The frequency method is an indirect method of measuring cable tension, in which using the relation between vibration frequency and cable tension, and measured frequency. It has been found wide use because of its simplicity, practicable use, higher accuracy and the instrument is easy to carry. The principle of the frequency method is based on the vibration theory of string or beam. The flexural rigidity of cable is ignored in string vibration theory, but included in beam vibration theory; therefore the latter is more approaching the engineering practice.

scholarly journals Design of Vibration Frequency Method with Fine-Tuned Factor for Fault Detection of Three Phase Induction Motor

2021 ◽  
Vol 3 (1) ◽  
pp. 52-65
Author(s):  
Thomas Amanuel ◽  
Amanuel Ghirmay ◽  
Huruy Ghebremeskel ◽  
Robel Ghebrehiwet ◽  
Weldekidan Bahlibi
Keyword(s):  
Induction Motor ◽  
Vibration Frequency ◽  
Vibration Monitoring ◽  
Slight Variation ◽  
Frequency Method ◽  
Monitoring Method ◽  
Stator Current ◽  
Research Article ◽  
Proposed Model ◽  
Fault Parameters

This research article focuses on industrial applications to demonstrate the characterization of current and vibration analysis to diagnose the induction motor drive problems. Generally, the induction motor faults are detected by monitoring the current and proposed fine-tuned vibration frequency method. The stator short circuit fault, broken rotor bar fault, air gap eccentricity, and bearing fault are the common faults that occur in an induction motor. The detection process of the proposed method is based on sidebands around the supply frequency in the stator current signal and vibration. Moreover, it is very challenging to diagnose the problem that occur due to the complex electromagnetic and mechanical characteristics of an induction motor with vibration measures. The design of an accurate model to measure vibration and stator current is analyzed in this research article. The proposed method is showing how efficiently the root cause of the problem can be diagnosed by using the combination of current and vibration monitoring method. The proposed model is developed for induction motor and its circuit environment in MATLAB is verified to perform an accurate detection and diagnosis of motor fault parameters. All stator faults are turned to turn fault; further, the rotor-broken bar and eccentricity are structured in each test. The output response (torque and stator current) is simulated by using a modified winding procedure (MWP) approach by tuning the winding geometrical parameter. The proposed model in MATLAB Simulink environment is highly symmetrical, which can easily detect the signal component in fault frequencies that occur due to a slight variation and improper motor installation. Finally, this research article compares the other existing methods with proposed method.

Thermal Performance Improvement of a Heat Sink With Piezoelectric Vibrating Fins

2010 ◽  
Author(s):  
Hee Seung Park ◽  
Sung Jin Kim
Keyword(s):  
Natural Frequency ◽  
Performance Improvement ◽  
Thermal Performance ◽  
Vibration Frequency ◽  
Heat Sink ◽  
Vibration Amplitude ◽  
Piezoelectric Actuators ◽  
Convection Heat ◽  
Heat Transfer Characteristics ◽  
Heat Sink Temperature

A heat sink with piezoelectric vibrating fins is developed through attaching piezoelectric actuators to the fins of a heat sink, and the heat transfer characteristics of the heat sink are experimentally investigated. Thermal performance improvement of the heat sink by the vibration of the fins is observed compared to the thermal performance of a natural convection heat sink with static fins under a fixed heat sink geometry condition. The thermal performance of the heat sink changes as the vibration amplitude of the fins or the vibration frequency of the fins changes. Particularly, if the vibration frequency of the fins matches up to the natural frequency of the fins, the vibration amplitude is significantly increased by resonance and the thermal performance also increases. The natural frequency of the fins changes with the heat sink temperature because the geometry of the fins changes and the properties of the fins change due to the temperature change.

Effects of Ceramsite Concrete Strength on Natural Frequency Based on ANSYS

2012 ◽  
Vol 204-208 ◽  
pp. 4124-4127
Author(s):  
Hao Qing Wang ◽  
Qiu Kong ◽  
Zhou Ping Yu ◽  
Wei Jun Yang
Keyword(s):  
Natural Frequency ◽  
Seismic Design ◽  
Vibration Frequency ◽  
Concrete Strength ◽  
Reinforcing Steel ◽  
Material Parameters ◽  
Modeling Analysis ◽  
Steel Bar ◽  
Environmental Vibration

By separate modeling analysis based upon ANSYS, SOLID65 unit of the entity is selected to simulate ceramsite concrete, and reinforcing performance is selected to simulate the effect of reinforcing steel bar. The strength on natural frequency’s effects was studied through changing the ansys model’s material parameters of ceramsite concrete. The strength of ceramsite concrete can be determined and applied to the anti-seismic design according to the size of the environmental vibration frequency.

Effects of Fixed Versus Variable Reference Frequencies on Psychophysical Judgments of Vibration

1978 ◽  
Vol 20 (1) ◽  
pp. 97-102 ◽  
Author(s):  
B.K.N. Rao ◽  
B. Jones
Keyword(s):  
Vibration Frequency ◽  
Reference Stimulus ◽  
Reference Frequency ◽  
Matching Method ◽  
Variable Stimulus ◽  
Frequency Method ◽  
Fixed Reference ◽  
Frequency Magnitude

Equal magnitude contours for vibration were obtained by two methods from ten seated subjects exposed to sinusoidal vibrations in three axes. In the traditional “fixed reference frequency” method, subjects were asked to adjust the amplitude of vibration in order to match for equal vibratory magnitude of a variable stimulus (of from 1 to 30 Hz) to a fixed reference vibration stimulus. The reference stimulus corresponded to the ISO 1–4 min “reduced comfort boundary” level; i.e., 6 Hz at 0.9 m/s2 (rms acceleration) for vertical (±gz) axis and 1 Hz at 0.62 m/s2 rms acceleration for the lateral (±gy) and longitudinal (±gx) axes. In the modified “progressive matching” method, subjects were exposed initially to the same reference stimulus and matched the adjoining stimulus vibratory frequency magnitude to it. Then, however, the newly matched vibration frequency was used as the next reference stimulus, the subjects matched the adjoining frequency magnitude to this “new” reference stimulus, etc. over the same range of frequencies (from 1 to 30 Hz). The advantages and shortcomings of the two methods are discussed.

Modes of vortex formation and frequency response of a freely vibrating cylinder

2000 ◽  
Vol 420 ◽  
pp. 85-130 ◽  
Author(s):  
R. GOVARDHAN ◽  
C. H. K. WILLIAMSON
Keyword(s):  
Natural Frequency ◽  
Vibration Frequency ◽  
Critical Mass ◽  
Flow Speed ◽  
Total Force ◽  
Mode Transition ◽  
Lower Branch ◽  
Lower Amplitude ◽  
Total Phase ◽  
Wake Modes

In this paper, we study the transverse vortex-induced vibrations of an elastically mounted rigid cylinder in a fluid flow. We use simultaneous force, displacement and vorticity measurements (using DPIV) for the first time in free vibrations. There exist two distinct types of response in such systems, depending on whether one has a high or low combined mass–damping parameter (m*ζ). In the classical high-(m*ζ) case, an ‘initial’ and ‘lower’ amplitude branch are separated by a discontinuous mode transition, whereas in the case of low (m*ζ), a further higher-amplitude ‘upper’ branch of response appears, and there exist two mode transitions.To understand the existence of more than one mode transition for low (m*ζ), we employ two distinct formulations of the equation of motion, one of which uses the ‘total force’, while the other uses the ‘vortex force’, which is related only to the dynamics of vorticity. The first mode transition involves a jump in ‘vortex phase’ (between vortex force and displacement), ϕvortex, at which point the frequency of oscillation (f) passes through the natural frequency of the system in the fluid, f ∼ fNwater. This transition is associated with a jump between 2S [harr ] 2P vortex wake modes, and a corresponding switch in vortex shedding timing. Across the second mode transition, there is a jump in ‘total phase’, phis;total , at which point f ∼ fNvacuum. In this case, there is no jump in ϕvortex, since both branches are associated with the 2P mode, and there is therefore no switch in timing of shedding, contrary to previous assumptions. Interestingly, for the high-(m*ζ) case, the vibration frequency jumps across both fNwater and fNvacuum, corresponding to the simultaneous jumps in ϕvortex and ϕtotal. This causes a switch in the timing of shedding, coincident with the ‘total phase’ jump, in agreement with previous assumptions.For large mass ratios, m* = O(100), the vibration frequency for synchronization lies close to the natural frequency (f* = f/fN ≈ 1.0), but as mass is reduced to m* = O(1), f* can reach remarkably large values. We deduce an expression for the frequency of the lower-branch vibration, as follows:formula herewhich agrees very well with a wide set of experimental data. This frequency equation uncovers the existence of a critical mass ratio, where the frequency f* becomes large: m*crit = 0.54. When m* < m*crit, the lower branch can never be reached and it ceases to exist. The upper-branch large-amplitude vibrations persist for all velocities, no matter how high, and the frequency increases indefinitely with flow velocity. Experiments at m* < m*crit show that the upper-branch vibrations continue to the limits (in flow speed) of our facility.

Research on Monitoring and Control for Suspender Cable Tension of Half-Through Concrete Filled Steel Tube Arch Bridge

2013 ◽  
Vol 859 ◽  
pp. 131-134
Author(s):  
Fu Li Zhao ◽  
Yi Qiang Xiang ◽  
Qiang Qiang Wu
Keyword(s):  
Steel Tube ◽  
Calculation Formula ◽  
Test Results ◽  
Monitoring And Control ◽  
Frequency Method ◽  
Cable Tension ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cable Force ◽  
Force Calculation

The measurement accuracy of the cable tensions in the hanger rods of concrete filled steel tube arch bridges is important for the correct evaluation of bridges condition. Based on Jinpan Bridge-a half through concrete filled steel tube arch bridge with 80 m span in Tiantai, it was put forward the vibration frequency method for testing and evaluate suspender tensions with the help of analysis vibration characters of the suspender. The precision of cable force calculation formula was verified after comparing the practical tension with the designed tension obtained from tension jack method. Then, according to the test results and values predicted by the presented cable force calculation formula, the cable tensions were adjusted. Cable tension test results in the finished bridge show that this method is feasible.

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