Low Frequency Vibration Data Analysis via Digital Image Data of High Speed Camera

2010 ◽  
Author(s):  
Yih-Nen Jeng ◽  
Chia-Hung Wu ◽  
Chi-Hung Chang ◽  
Tzung-Ming Yang ◽  
Hau-Chang Hung
Keyword(s):  
Data Analysis ◽  
Digital Image ◽  
High Speed ◽  
Low Frequency ◽  
Image Data ◽  
High Speed Camera ◽  
Vibration Data ◽  
Low Frequency Vibration

scholarly journals Automated processing of railway track deflection signals obtained from velocity and acceleration measurements

2018 ◽  
Vol 232 (8) ◽  
pp. 2097-2110 ◽  
Author(s):  
David Milne ◽  
Louis L Pen ◽  
David Thompson ◽  
William Powrie
Keyword(s):  
Performance Monitoring ◽  
Low Frequency ◽  
Cumulative Distribution ◽  
Railway Track ◽  
Statistical Process ◽  
Vibration Data ◽  
Rest Position ◽  
Low Frequency Vibration ◽  
Automated Processing ◽  
And Performance

Measurements of low-frequency vibration are increasingly being used to assess the condition and performance of railway tracks. Displacements used to characterise the track movement under train loads are commonly obtained from velocity or acceleration signals. Artefacts from signal processing, which lead to a shift in the datum associated with the at-rest position, as well as variability between successive wheels, mean that interpreting measurements is non-trivial. As a result, deflections are often interpreted by inspection rather than following an algorithmic or statistical process. This can limit the amount of data that can be usefully analysed in practice, militating against widespread or long-term use of track vibration measurements for condition or performance monitoring purposes. This paper shows how the cumulative distribution function of the track deflection can be used to identify the at-rest position and to interpret the typical range of track movement from displacement data. This process can be used to correct the shift in the at-rest position in velocity or acceleration data, to determine the proportion of upward and downward movement and to align data from multiple transducers to a common datum for visualising deflection as a function of distance along the track. The technique provides a means of characterising track displacement automatically, which can be used as a measure of system performance. This enables large volumes of track vibration data to be used for condition monitoring.

Development of Small-Sized Motor-Driven Gyroscopic Power Generator Works Under Low-Frequency Vibration

2019 ◽  
Author(s):  
Akio Toyoshima ◽  
Hiroshi Hosaka ◽  
Akira Yamashita
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Spindle Motor ◽  
Inertia Force ◽  
Power Generator ◽  
Power Generators ◽  
Mechanical Parts ◽  
Low Frequency Vibration ◽  
Generator Type ◽  
Design Freedom

Abstract In order to realize a small-sized energy harvester with high output, this study prototypes a small motor-driven gyroscopic power generator. Supplying energy to sensors and devices is the biggest problem for Internet of Things (IoT) systems. One solution is gyroscopic power generators, which are a type of vibrational generator that amplify the inertia force of weights by rotating them at high speed, and in doing so can obtain greater output than conventional generators that use simple vibration for the same mass weight. This paper reports on a motor-driven type gyroscopic generator in which the flywheel is spun with an embedded motor, and which is superior in applicability to random vibration generators. The generators of this type that have been studied thus far are very large and have been primarily used for wave power generation in the ocean. However, when the shape of this gyroscopic power generator type is miniaturized proportionally, the output per volume decreases in proportion to the fifth power of the dimension. This makes it difficult to maintain the power output while miniaturizing the generator size. In this research, the structure of the gyroscopic power generator is thoroughly refined and miniaturization is realized by making full use of the available space. By using a motor with high design freedom, the spindle motor and flywheel are unified. From this accomplishment, not only is the required space reduced, the number of mechanical parts and the friction loss are decreased as well. The prototype generator has a size of about 150 mm on its long side. When a swinging vibration of 50 degrees in amplitude and 2 Hz in frequency is applied, a net output of 0.104 W is obtained. This output power is sufficient to drive sensors and low power wide area (LPWA) radio circuits.

Fundamental Study on Friction-Driven Gyroscopic Power Generator Works Under Arbitrary Vibration

2019 ◽  
Author(s):  
Aya Watanabe ◽  
Ryousuke Yuyama ◽  
Hiroshi Hosaka ◽  
Akira Yamashita
Keyword(s):  
Power Generation ◽  
High Speed ◽  
Electrical Power ◽  
Low Frequency ◽  
Inertial Force ◽  
Fundamental Study ◽  
Power Generator ◽  
Energy Harvesters ◽  
Low Frequency Vibration ◽  
Circular Track

Abstract This paper describes a friction-driven gyro generator that works under arbitrary vibrations and generates more than 1 W of power. Vibrational generators are energy harvesters that convert environmental vibrations into electrical power via the inertial force of pendulums. In conventional generators that use simple vibration, the power is less than 10 mW for a wearable size because vibrations in the natural environment are as low as 1 Hz. Gyroscopic generators increase the inertial force by rotating a pendulum at high speed and creating a gyro effect. In this generator, a palm-size product that generates 0.1 W and weighs 280 g has already been commercialized, but this device operates only under a particular vibration that synchronizes rotor precession and stalls under random vibration. To solve this problem, in this research, two gimbals and a precession spring are introduced to support the rotor. We developed a prototype generator with straight tracks measuring 16 cm × 11 cm × 12 cm with a mass of 980 g. Under a vibration of 4 Hz and ±20 degrees, power generation of 1.6 W was confirmed. Next, a prototype circular track was made. Power generation of 0.2 W with a vibration of 1 Hz and ±90 degrees was confirmed. Finally, a simple formula to estimate the upper limit of the generation power is derived. It is suggested that the circular-type generator is suitable for low-frequency vibration and can generate twice the power of a straight-type generator.

scholarly journals Dynamic Characteristics of Gear Coupling and Rotor System in Transmission Process Considering Misalignment and Tooth Contact Analysis

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1336
Author(s):  
Wei Fan ◽  
Hong Lu ◽  
Yongquan Zhang ◽  
Xiangang Su
Keyword(s):  
Finite Element ◽  
Dynamic Model ◽  
Calculation Method ◽  
High Speed ◽  
Low Frequency ◽  
Rotor System ◽  
Integral Approach ◽  
Time Frequency ◽  
Low Frequency Vibration ◽  
Mass Eccentricity

The dynamic vibration of the gear coupling-rotor system (GCRS) caused by misalignment is an important factor of low frequency vibration and noise radiation of the naval marine. The axial misalignment of gear coupling is inevitable owing to mass eccentricity, and is unconstrained in axial direction at high-speed operation. Therefore, the dynamic model of GCRS is proposed, considering gear-coupling misalignment and contact force in this paper. The whole motion differential equation of GCRS is established based on the finite element method. Moreover, the numerical calculation method of meshing force, considering the uniform distribution load on contact surface, is presented, and the mathematical predictive time–frequency characteristics are analyzed by the Newmark stepwise integral approach. Finally, a reduced-scale application of the propulsion shaft system is utilized to validate the effectiveness of the proposed dynamic model. For the sensibility to low-frequency vibration, the natural frequencies and vibration modes of GCRS are analyzed through the processing and analysis of acceleration signal. The experimental dynamic response and main components of vibration are respectively consistent with mathematical results, which demonstrate the effectiveness of the proposed dynamic model of GCRS with misalignment. Furthermore, it also shows that the proposed finite element analysis and calculation method are suitable for complex shafting, providing a novel thought for dynamic analysis of the propeller–shaft–hull coupled system of marine.

Wireless impedance device for electromechanical impedance sensing and low-frequency vibration data acquisition

2009 ◽  
Author(s):  
Stuart G. Taylor ◽  
Kevin M. Farinholt ◽  
Gyuhae Park ◽  
Charles R. Farrar ◽  
Eric B. Flynn ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Low Frequency ◽  
Impedance Sensing ◽  
Electromechanical Impedance ◽  
Vibration Data ◽  
Low Frequency Vibration

scholarly journals Application of Digital Image Correlation to Measurement of Packaging Material Mechanical Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jian-Wei Zhou ◽  
Dong-Hong Liu ◽  
Lan-Yuan Shao ◽  
Zhen-Lin Wang
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Poisson Ratio ◽  
Low Frequency ◽  
Measurement Range ◽  
Image Correlation ◽  
Packaging Materials ◽  
Entire Area ◽  
Low Frequency Vibration

Among various packaging materials, papers and polymer plastics are the most common due to their light weights, low costs, and other advantages. However, their mechanical properties are difficult to measure precisely because of their softness. To overcome the difficulty, a new measure instrument prototype is proposed based on an optical method known as the digital image correlation (DIC). Experiments are designed to apply the DIC to measure mechanical properties of flexible packaging materials, including the stress-strain relationship, the Poisson ratio, the coefficient of heat expansion, the creep deformation, and the top-pressure deformation of corrugated box. In addition, the low frequency vibration of package is simulated, and the vibration frequencies are measured by DIC. Results obtained in the experiments illustrate the advantages of the DIC over traditional methods: noncontact, no reinforced effect, high precision over entire area, wide measurement range, and good measurement stability.

Stress and Strain Analysis of SRM Based on Monitored Shipboard Service Environment

2013 ◽  
Vol 275-277 ◽  
pp. 731-735
Author(s):  
Wei Dong Huang ◽  
Li Ping Zhang
Keyword(s):  
Low Frequency ◽  
Strain Analysis ◽  
Stress And Strain ◽  
Solid Rocket Motor ◽  
Vibration Load ◽  
Service Environment ◽  
Vibration Data ◽  
Low Frequency Vibration ◽  
Effects Of Temperature ◽  
Solid Rocket

Shipboard service environment of solid rocket motor (SRM) was monitored. Based on the monitored temperature and vibration data, the effects of temperature and low frequency vibration load on the stress and strain of SRM were analyzed by ABAQUS. It was shown by the results that the stress and strain of gain fluctuated near the initial thermal stress and strain with the low frequency vibration load. It was also found that the variations in stress and strain of the bonding interface were larger than that of the slot.

Sign in / Sign up

Export Citation Format

Share Document