Papers by Keyword: Vibration

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Authors: Bing Bai, Li Xing Zhang
Abstract: To calculate the characteristics of the lateral vibration in the main shaft system of the hydro-turbine generating set, a three-node elastic shaft element was proposed. Its dynamic equation was derived and the interpolation function, translational inertia matrix, rotational inertia matrix, gyroscopic matrix and the stiffness matrix were obtained. Based on Matlab platform, a FEM program was developed for calculation and its correctness was verified through a numerical example. The study shows that, compared with the method using two-node shaft element, the results of the three-node shaft element are closer to the theoretical solution and the accuracy is higher.
Authors: Ming Yang, Jin Yao Li, Jia Cong Chen, Shi Jia Kong
Abstract: At the development of modern printing, vibration may course some products quality problems when increases the speed. Practical experience shows that the mechanical vibration of the offset press is an important reason to affect the print quality. Therefore, improving the vibration performance of the printing press and designing the structure of anti-vibration and noise reduction to improve the quality and speed of printing presses is an important issue in the press product development. This paper proposes some reasons and solution ideas of vibration on printing parts in ordinary offset printing machines.
Authors: Hua An Ma, Jing Quan Liu, Gang Tang, Chun Sheng Yang, Yi Gui Li, Dan Nong He
Abstract: As the low-power wireless sensor components and the development of micro electromechanical systems, long-term supply of components is a major obstacle of their development. One of solutions to this problem is based on the environmental energy collection of piezoelectric vibration energy harvesting. Currently, frequency band of piezoelectric vibration energy harvester is narrow and the frequency is high, which is not fit for the vibration energy acquisition in the natural environment. A piezoelectric vibration energy harvester with lower working frequency and broader band is designed and a test system to analyze the harvester is presented in this paper. The traditional mass is replaced by a permanent magnet in this paper, While other two permanent magnets are also placed on the upper and above of the piezoelectric cantilever. Experiments showed, under the 0.5g acceleration, compared with the traditional non-magnetic piezoelectric vibration energy harvesting, a piezoelectric cantilever (length 40mm, width 8mm, thickness 0.8mm) has a peak-peak voltage of 32.4V, effectively enlarges working frequency band from 67HZ-105HZ to 63HZ-108HZ.
Authors: Octavia Borcan
Abstract: Most often observation with a thermal camera is not static; the platform on which the surveillance equipment is mounted is affected both by motor vehicle exterior vibrations and amplitudes of the movement in field. In this paper a case study is shown starting from some tests made on a moving boat and a visual method to analyze the motion is presented. Some images acquired in real time are fast and automatic analyzed using NIVision software to quantify the random and the sinusoidal motion made by the motor vibrations and the motion of the platform. Due to this phenomenon the images seems to be blurred but this blurring can be anticipated and avoided through a proper design of platform stabilisation if the motion parameters are known.
Authors: He Sheng Tang, Jie Wang, Jia Wu Shi
Abstract: A coupled finite element–thin layer element (FE-TLE) model for the prediction of subway induced vibrations was developed. With this model, the soil-tunnel system is divided into two parts, i.e., the tunnel structure and layered soil with a tunnel type hole. The tunnel structure is simulated by finite elements and the layered soils with hole by thin layer elements. The model fully accounts for the dynamic interaction between the tunnel and the soil. The numerical models for train-induced ground-borne vibrations were validated by in-situ experiments.
Authors: Yasushi Ido, Koichi Hayashi, Takahiro Kunitomo
Abstract: A coupled system of a magnet and magnetic fluid is used as a piston in a U-tube. Applying reciprocating travelling magnetic field produces reciprocating motion of the coupled system. In this study, vibration properties of the coupled system are investigated experimentally. Three types of vibration mode of the coupled system appear and the mode depends on the frequency and intensity of travelling magnetic field and the shape of the magnet. Basically the coupled system follows the travelling magnetic field in the range of low frequency, while the system cannot follow the travelling field when the frequency of the travelling magnetic field is high. However, when the magnet is sphere or short cylinder, the other type of vibration appears in the range of low frequency and the coupled system intermittently tracks the travelling magnetic field.
Authors: Xue Feng He, Yao Qing Cheng, Jun Gao, You Zhu
Abstract: To harvest ambient vibration energy of different directions, a micromachined vibration energy harvester which can harvest two-dimensional vibration energy was proposed. The harvester is composed of a curled piezoelectric cantilever, a proof mass and the substrate. One end of the cantilever is fixed onto the substrate and the other end is connected with a proof mass. It is the residual stress of micromachining processes that causes the cantilever to curl. A proof-of-concept prototype of the two-dimensional vibration energy harvester was assembled and tested to evaluate the performance. Experimental results show that the vibration direction with the highest energy scavenging efficiency changed with the frequency of the ambient vibration. The vibration energy of any direction in the neutral plane of the curled cantilever can be harvested by using the first two natural vibration modes of the prototype.
Authors: Ju Young Yun, Yong Hyeon Shin, Kwang Hwa Chung
Abstract: In examining particulate deposits in the pipes within a chemical vapor deposition (CVD) system, vibration diagnostics is compared and studied against ultrasonic diagnostics. The latter method involves pulsing the outer wall of pipes with an ultrasonic sensor and analyzing the resulting echo to observe particulate deposits inside pipes. Vibration diagnostics examines the existence of particulate deposits by analyzing the difference in the frequencies generated when a vibrator is adhered to the outer wall of pipes. With ultrasonic diagnostics, good test results were obtained only when particulate deposits were attached to the inner wall of the pipes. After some time, however, particulate deposits were not detected properly, as the ultrasonic wave failed to cross the fine gaps created between the inner wall of the pipe and the deposits. In conclusion, the vibration diagnostics is being expected as the effective method in monitoring the particulate deposits inside pipes in the CVD system where the desired behavior is reduced frequency along with the the particulate deposits in comparison to the case where the pipe is clean.
Authors: Mohd Idrus bin Mohd Masirin, Nur Farrina Johari, Noor Hafiza Nordin, Abdul Halid Abdullah, Mohd Isom Azis
Abstract: Malaysia is a fast developing country which thrives on the growth of its population and economy. Kuala Lumpur is the capital of Malaysia with an area of 243 km2 has a population of 1.4 million [1]. From the statistics, the number of passengers using intercity train services in Malaysia in was 187,345,149 in the year 2012 [2]. Comfortability of a service is a major factor that influences the public. The research will be conducted at the City of Kuala Lumpur, PUTRA LRT (Kelana Jaya Line) and MONOREL Line is selected as the main focus of the research. The data collection will be conducted in the train coaches with two parameters. The noise and vibrations in the train coaches will be taken using the Sound Level Meter (NOR118) and Vibration Meter (Movipack 01dB-Steel) respectively. The noise data were obtained from the interior of the train coaches during operation, while the vibrations were obtained from the wall surface of the coach interior. The vibration aspect for this research is more focused on three parameters which are displacement (μm), vibration velocity (mm/s) and vibration frequency (Hz)[7]. Questionnaires were given out to the train passengers in order to obtain public opinions and satisfaction feedbacks relating their experiences on the train coaches. In this paper it also discusses on the outcomes of the field research work conducted and it was found that PUTRA LRT has a lower vibration value when compared to the MONOREL. The public opinion has also showed unanimous agreement to the field observations conducted by the researchers. However, MONOREL records lower noise levels compared to PUTRA LRT which means quieter journey experience to the commuters. It is hoped that this study will enable the operators to enhance their service weaknesses with the public playing a part in improving the urban rail transit in the City of Kuala Lumpur. Keywords: Comfortability, Noise, Vibration, LRT, MONOREL,
Authors: Yu Jie Guo, Jing Yu Liu, Jie Li, Zhan Hui Liu, Wen Tao Zhang
Abstract: Envelope analysis is the popular fault diagnosis method of rolling bearing. It can diagnosis rolling bearing fault, such as inner race fault and outer race fault. The traditional envelope analysis is set up on the measured acceleration signal. It is influenced by noise seriously, especially in bearing early fault stage. Research shows that the amplitude modulation phenomenon can be enlarged if the envelope analysis is done for the auto-correlation signal. Vibration test was done for a driving motor with fault rolling bearing. Factors influencing the effect of envelope analysis were analyzed.
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