scholarly journals Study on applicability of a contactless measurement method for vibration stress using laser displacement sensors

2015 ◽  
Vol 81 (831) ◽  
pp. 15-00195-15-00195 ◽  
Author(s):  
Akira MAEKAWA ◽  
Michiyasu NODA ◽  
Masanori SHINTANI ◽  
Michiaki SUZUKI
Author(s):  
Akira Maekawa ◽  
Takashi Tsuji ◽  
Tsuneo Takahashi

Abstract The present paper proposes an improved contactless measurement method for vibration stress of piping systems, by which the measurement time is shorter and the measuring works are more simple. The proposed method includes two processes, in which the bending mode shape of piping vibration is identified by a transmission-type light emitting diode (LED) displacement sensor and the vibration stress is calculated based on beam theory using the approximated curve of the bending mode shape. The proposed method uses one advanced LED displacement sensor to measure the vibration stress though multiple conventional LED sensors must be used in the previous method developed by the authors. Therefore, the measuring system could be reduced in size and a light-weight and portable measurement instrument was developed. The measurement accuracy and reliability of the new method were validated by the vibration experiment using a mock-up piping system.


Author(s):  
Akira Maekawa ◽  
Tsuneo Takahashi ◽  
Takashi Tsuji ◽  
Michiyasu Noda

In nuclear power plants, vibration stress of piping is frequently measured to prevent the occurrence of fatigue failure. A simpler and more efficient measurement method is desired for rapid integrity evaluation of piping. In this study, a method to measure vibration stress in a noncontact manner using optical displacement sensors is presented and validated. The proposed method estimates vibration-induced stress of small-bore piping directly using noncontact sensors based on a light-emission diode. First, the noncontact measurement method was proposed, and the measurement instrument based on the proposed method was developed for the validation. Next, vibration measurement experiments using the instrument were conducted for a mock-up piping system and an actual piping system. The measurement results were compared with the values measured by the conventional method of known accuracy using strain gauges. From this comparison, the proposed noncontact measurement method was demonstrated to be able to provide sufficient accuracy for practical use.


Author(s):  
Akira Maekawa ◽  
Takashi Tsuji ◽  
Tsuneo Takahashi

The present paper proposes an efficient contactless measurement method for vibration stress of piping systems, by which the measurement tasks are performed within an extremely short time and the measured stress can be evaluated immediately after the measurement. The proposed method includes two processes, in which the bending shape of a pipe induced by vibration response is identified by a transmission-type optical displacement sensor and the vibration stress is calculated based on beam theory using the curvature radius estimated by approximating the bending shape. The proposed method uses only one LED-optical sensor to measure the vibration stress though multiple sensors must be used in the previous method developed by the authors. Therefore, the measuring system could be reduced in size and a light-weight and portable measurement instrument was developed. The measurement accuracy and reliability of the new method were verified by the vibration experiment using a mock-up piping system.


2018 ◽  
Vol 157 ◽  
pp. 05023
Author(s):  
Martyna Zowade ◽  
Maciej Bodnicki

The aim of the work was to design a special system for measurements of elements with repetitive geometry or assemblies with repeating components, set in a linear patterns. The main focus was based on developing a computer program for signal analysis from variable number of miniature displacement sensors. It was set that the response for displacement of measuring tip from each sensor was a 0-5 V voltage signal with possibility of using different type of sensors. Requirements were determined based on projected measurement method. A special design of sensor was made for testing the computer program. If the characteristics of the sensor is known, it is possible to compute the type A evaluation of uncertainty. The results are presented in XY chart on computer screen. The program allows the user to choose any number of the sensors and determine the distance between them. Also, the possibility of calibration of sensors’ set was provided. The test were conducted on a prototype handle for sensors, made on a 3D printer.


2006 ◽  
Vol 505-507 ◽  
pp. 349-354
Author(s):  
Yeh Fen Fu ◽  
Lih Horng Shyu ◽  
Y.T. Chen ◽  
Wen Yuh Jywe ◽  
C.H. Liu

A new optical encoder system is presented for displacement measurement by the curve fitting method. In this paper, another pondering model is based on the previous development. That is the new measurement method using a homemade periodical gray level code, which can be used to replace the traditional doublet grating. A high precision is achieved by a fitting method with one single-frequency harmonic function. The experiment result shows that the concept is feasible.


1986 ◽  
Vol 108 (3) ◽  
pp. 176-182 ◽  
Author(s):  
H. Tanaka ◽  
H. Sato

Characteristics of errors which might occur in the straightness measurement method due to sequential-two-points were investigated. The investigation made it clear that the slight discrepancies of alignment at the tip between two displacement sensors would be accumulated onto the portion of linear increment generally observed when the straightness is measured; the method of compensation is analytically shown. It is theoretically proposed that the error which might be introduced by the yaw of the tool post and is neglected by the present system can be evaluated by the measurement using sequential-three-points. It is also shown that the measurement system due to the sequential-two-points works stably even for the case when the work on the lathe is rotated. The cylindricity obtained by the measurement during the work rotation agrees well with that obtained by static measurements.


2013 ◽  
Vol 373-375 ◽  
pp. 790-794 ◽  
Author(s):  
Rong Sheng Qiu ◽  
Xiao Lin Wang ◽  
Yong Ming Pan

A new flatness error measurement method was proposed for large quantities of E-type AC relay, which was consisted of three discontinuous plane. The research object of this thesis is on both sides of the work piece plane. The relay was measured by utilizing multiple laser displacement sensors, and used the development of PC software to extract the measurement key points and process the collected data, which was used the method of least squares to calculate more accurate flatness error value. This method can achieve substandard work-piece fast sorting and rapid online measure.


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