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Difference between revisions of "Human Vibration"
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→Practical information about measurements
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This section will provide you with some practical informations about Human Vibration evaluations. | This section will provide you with some practical informations about Human Vibration evaluations. | ||
Human vibrations are | Human vibrations are transmitted to the human body over a reasonable amount of time. This transmission mainly happened in vehicle during transportation, in buildings, and when using vibrating equipments and tools, such as electric drills, blowers... are manipulated. Since the last century, quantities of studies showed that vibrations can have many affect on the human body, from discomfort and transport sickness to serious health issues, including blood flow disorder to muscular and rheumatisms.<br> | ||
Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm.<br><br> | Therefore, methods of measurement and evaluation of these vibrations have been developed over the year, and translated into several standards for mechanical appliances to prevent discomfort and harm.<br><br> | ||
===Type of measurement=== | ===Type of measurement=== | ||
====Whole-Body Measurement==== | |||
Measurement procedures for whole-body vibration evaluation are describe in the ISO2631. That type of vibration will mainly occur in transportations and in the workplace when working with big machinery. Therefore, the evaluation of the vibration will be carried on the part supporting the human body, like backside and feet for a seated person and feet for a standing person. Sensors must be placed to assess vibration to these specific points. Measurement must be carried on the complete system. Meaning the user must be present during the measurement and operate the machine/vehicle as usual. The following picture, exctracted from the standard, give indication over the orientation of the sensors : <br> | |||
[[Image:Axis_WholeBody.png]] | |||
For each point, the vibration must be measured in the three direction X, Y and Z. AS different weighting will be used for each direction, it is really important that each sensors are oriented according to the same directions. The Z direction must always used in the direction of the human spine.<br> | |||
Specific sensors must be used in order to detect vibration at the transmission point. For a seated person, [[https://www.dytran.com/Search/?searchText=seat+pad|Seat Pad accelerometer]] allow to acquire vibrations at the buttock of the seated person. If necessary, same kind of sensors can by used under the feet of a standing person. These sensor must be fixed to hold in place when the subject move. For vibration transmitted to feet, standard accelerometers can also be placed on the floor.<br> | |||
There is no precise rules about the lenght of the measurement. However, the ISO 2631 specify that measurement must be taken for at least 20 minutes, | |||