Gracey & Associates
Noise and Vibration
Glossary - V
GLOSSARY INDEX:
A B C
D E F
G H I
J K L
M N O
P Q R
S T U
V W X
Y Z
VDV : Vibration Dose Value .
Vector : a quantity having both magnitude and direction, especially as determining the position of one point in space relative to another.
Velocity : v : the rate of change of position and is a vector quantity as both speed and direction are required to define it. The SI units are metres per second: (m/s).
v = u + at where v = velocity, u = start velocity, a = acceleration in m/s2 and t = time.
In the field of vibration acceleration a, velocity v, displacement s and angular frequency ω are related. - for example v = a/ω, s = v/ω, where ω = 2·π·f
It follows that 10 m/s2 = 0.01 m/s = 10 μm at 159 Hz
This works for all frequencies, we just chose 159 Hz to keep the numbers simple. We also have a vibration nomogram for downloading.
See also sound particle velocity.
Velocity Level : Lv : = 20 log(v/vo) dB re 10-8 m/s = 10-6 cm/s
an increase or decrease in velocity of 20 dB = a factor of 10
a 40 dB = a factor of 100
a 60 dB = a factor of 1000 ... etc.,
See also the table of decibel reference levels.
Vibration : mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random.
Vibration is commonly expressed in terms of
acceleration, velocity, displacement and frequency which are related.
See also the table of decibel reference levels.
Vibration at Work Regulations : The Control of Vibration at Work Regulations 2005 (the Vibration Regulations), came into force on 6 July 2005 and aim to protect workers from risks to health from vibration. The regulations introduce action and limit values for hand-arm and whole-body vibration.
see also the acceleration equivalent value : Aeq and hand-arm vibration syndrome : HAVS
Vibration Dose Value : VDV : cumulative measurement of the vibration level received over an 8-hour or 16-hour period. It is the integrated fourth power vibration value with units m/s1.75 and has the advantage of sensitivity to vibration peak levels.
See also whole body vibration and see the Vibration at Work Regulations.
Vibration Weighting Networks
Vibration White Finger : VWF : see also Hand-arm Vibration Syndrome.
Volume : V : the SI unit is the cubic metre : m3
Volumetric Flow : also known as volume flow rate or rate of fluid flow is the volume of fluid which passes through a given surface per unit time, the units are - m3/s
Volumetric Power Density : volume based power density - watt/m3
VWF : Vibration White Finger : Hand-arm Vibration Syndrome.
GLOSSARY INDEX:
A B C
D E F
G H I
J K L
M N O
P Q R
S T U
V W X
Y Z
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- Gracey & Associates 01933 624212
- BSI accreditation for noise and vibration instrument hire
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