레이블이 #vibration analysis인 게시물을 표시합니다. 모든 게시물 표시
레이블이 #vibration analysis인 게시물을 표시합니다. 모든 게시물 표시

2024년 2월 28일 수요일

BISOPE series 56 vibration and machine condition


BISOPE series 56- Vibration and machine condition

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If the body temperature measured in a person is too high or too low, everyone agrees that they are not feeling well. I think this premise is natural because we have learned it through numerous results for a long time even if we do not know science. An auditor asked a question. He appeared to be a mid-level researcher, and this was a novel idea I had never heard before. “Is high vibration a bad condition for the machine? Why do you say that premise is obvious?” All the other auditors next to him looked at him strangely, but I could only answer indirectly, “Vibration, like temperature, expresses a state.”

 

Vibration signals include the state of the machine.

This is written on the front page of the basic textbook of a renowned professional company that performs equipment diagnosis through vibration. ‘The vibration signal you are currently measuring from the machine contains all the defect signals of the machine. By analyzing these signals well, the machine can tell where the pain is.’

 Now let me say it again. ‘The state of a moving machine can be judged by vibration.

 

https://blog.naver.com/vs72

#PDM, #predictive maintenance, #equipment diagnosis, #vibration, #machine diagnosis, #vibration analysis, #vibration defect, #condition diagnosis, #CBM, #machine condition and vibration

 


2022년 11월 2일 수요일

BISOPE series 20 Why is there a difference in the speed of sound in sol...


BISOPE series 20- Why is there a difference in the speed of sound in solids and gases?

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Why is there a difference in the speed of sound in solids and gases?

 

The speed at which sound waves propagate through a medium is the definition of sound speed. The medium itself does not move, it is the propagation speed of the phase of the sound wave. When looking at the wavelength as the origin, sound waves in a narrow sense propagate through the fluid as longitudinal waves (penetrating the medium in the propagation direction), and their speed varies depending on the conditions of the medium such as temperature and humidity and the type of medium.

 

Change in momentum and rate of volume change

 

​The propagation speed of longitudinal waves is determined by the mechanical properties of the medium. Considering the change in momentum of the fluid moving in the piston (vt) with a certain cross-sectional area (A), it can be viewed as the product of the mass (ρvtA) of the fluid and the change in velocity (u). On the other hand, when the pressure increase Δp in the moving fluid is obtained, the initial volume Avt of the fluid in motion is decreased by Aut, so from the definition of the bulk modulus (;- pressure change/volume change rate)

 

Velocity of sound, modulus of elasticity - https://blog.naver.com/vs72

 

is established At this time, 'B' is the bulk modulus, and when the medium is a fluid, it corresponds to the volume modulus (volume change rate), and when the medium is a solid, it corresponds to the Young's modulus. Since it is larger than the bulk modulus of , the velocity in the medium of longitudinal waves is ultimately influenced by the difference in the velocity of sound by the difference in the volume modulus rather than the difference in the density. V solid > V liquid > V gas !

 

Difference in speed of sound - https://blog.naver.com/vs72

 

What is the difference between the speed of sound and the speed of particles?

 

As the speed at which sound waves propagate through an elastic medium, the formula is the same as above, and among them, the speed of sound in the air is expressed conveniently and c=20.06√T in relation to temperature.

On the other hand, particle velocity (v) is the vibration velocity of a medium that transmits sound waves, and when it is assumed as a plane wave, it can be expressed as v=p/ρc. (T: absolute temperature, p: pressure, ρ: density, c: speed of sound)

 

 

 

Wavelength, particle velocity - https://blog.naver.com/vs72

 

speed of sound in different media

​All copyright Korea CBM Co., Ltd. written by BISOPE

 

#vibration measurement, #vibration analysis, #frequency analysis, #resonance measurement, #resonance analysis, #3-axis vibration, #accelerometer, #fft, #bearing vibration, #vibration noise education, #equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear movement, #visope, #looseness, #environmental vibration, #rotating machine, #vibration education, #vibration monitoring, #balancing, #volume modulus, #sonic velocity, #noise and vibration

All copyright  korea CBM  written by BISOPE , vs72@naver.com, 070-4388-0415,  www.kCBM.kr



#vibration measurement, #vibration analysis, #frequency analysis, #resonance measurement, #resonance analysis, #3-axis vibration, #accelerometer, #fft, #bearing vibration, #vibration noise education, #equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear movement, #visope, #looseness, #environmental vibration, #rotating machine, #vibration education, #vibration monitoring, #balancing, #volume modulus, #sonic velocity, #noise and vibration