BS ISO 8608:2016 pdf free
BS ISO 8608:2016 pdf free.Mechanical vibration一Road surface profiles一Reporting of measured data
The reported PSD shall be restricted between the limits allowed by the measuring equipment. For the report, the user may select any spatial frequency range appropriate to his/her particular road surface,problem and product.
The measured surface depends on the measuring equipment, which has a certain smoothing effect.This equipment is to be reported (see Note 4 and 5.3.5.2.1).
NOTE 1 Figure C.1 gives the relationship between the vehicle speed, the spatial frequency and the time frequency. Knowledge of the frequency and speed characteristics for a given class of vehicles makes it possible to choose the useful limits for that class of vehicle (e.g. on-road or off-road vehicles).
NOTE 2 For the lower limit, the spatial frequency need not in general be measured lower than 0,01 cycles/m for on-road vehicles and 0,05 cycles/m for off-road vehicles.
NOTE 3 The enveloping effect of the tyre acts as a low-pass filter for the road vibration input to the vehicle.This effect depends on the size and construction of the tyre. For general on-road measurements, this results in a recommended upper limit of 10 cycles/m. Of course for suspension vibration purposes, the interesting upper limit depends on the maximum allowed speed on the particular road. For noise purposes, the interesting upper limit may be much higher, and may go as high as 1 000 cycles/m.
NOTE 4 Due to the tyre width there is also an enveloping effect in the lateral direction. This means that for vibration purposes, the mean of the footprint is usually measured. The width depends on the problem (e.g. vibration, noise) and the product (e.g. motorcycle tyres, truck tyres). For general on-road measurements not intended for a specific product, a track of about 100 mm wide is often used for vibration purposes. For noise purposes, a point measurement is often used.
NOTE 5 For off-road measurements, care needs to be taken when interpreting the high frequencies. For soft (e.g. sandy) surfaces, short undulations could be flattened by the wheel load and filtered out. For hard (e.g. stone) surfaces, however, only the enveloping effect of the tyre acts as a filter. In this situation, the surface needs to be described accurately in the data sheet (see 5.3.5.3.2).
NOTE 6 Annex B gives recommended methods for the characterization of the road profile and for the fitting of the measured data.BS ISO 8608 pdf download.
