AS ISO 7096:2021 – Earth-moving machinery -Laboratory evaluation of operator seat vibration
AS ISO 7096:2021 – Earth-moving machinery -Laboratory evaluation of operator seat vibration.
The seat shall be loaded with an inert mass of 75 kg and then excited by a sinusoidal vibration In the range from 0,5 to 2 times the expected resonance frequency of the suspension. The inert mass shall, if necessary, be secured to the seat in order to prevent the mass from moving on the seat or from falling off it.
Bags filled with lead shot or other material with similar density should be used as inert mass.
To determine the resonance frequency, the frequency range shall be investigated with either a linear frequency sweep or in maximum steps of 0,05 Hz. With either method, the frequency should he varied from a lower frequency (equal to 0,5 times the expected resonance of the suspension) to an upper frequency (equal to 2 times the expected resonance frequency of the suspension) and back again to the lower frequency. The frequency sweeping shall he made over a duration of at least 80 S at a constant peak to peak displacement of the platform that is equal to 40% of the total suspension travel (stroke) specified by the seat manufacturer, or 50 mm, whichever is the smaller.
The damping test and the calculation of the transmissibility II(fr) at resonance shall be performed according to ISO 10326-1:2016, 9.5. In all cases, the damping test itself at the resonance frequency shall be carried out with a peak to peak displacement of the platform of 40% of the total suspension travel even lithe 40% value exceeds 50 mm.
Only one measurement needs to be carried out at the resonance frequency of the seat’s suspension.
5.5.3 Damping test for active and semi-active suspension systems
For active and semi-active suspension systems, the simulated input vibration test shall be performed as for passive systems. The damping test shall be performed at the frequency of highest response in the range of (0,1 to 10) Hz. The frequency of highest response can be different than the suspension’s resonant frequency.
5.6 Tolerances on input vibration
See in ISO 10326-1:2016,9.3.
The input excitation for the seat as defined In 5.5.1 can only be created on a simulator in an approximate manner. In order to be valid the test input shall comply with the following requirements.
5.6.2 DistrIbution function
Under the condition that the acceleration on the platform shall be sampled at a minimum of 50 data points per second and analyzed into amplitude cells of not greater than 20 % of the total true rms acceleration, the probability density function must he within ±20 % of the ideal Gaussian function between ±200 % of the total true rms acceleration, and with no data exceeding ±350 % of the total true rms acceleration. For the purposes of this requirement, the total true rms acceleration is ap as defined in Table 4.
5.6.3 Power spectral density and rms values
The power spectral density of the acceleration measured on the platform is considered to be representative oIGpIJ) if, and only if:
7 Seat identification
The seat shall be identified by a permanent mark at a clearly visible location. The mark shall include the Following information:
— manufacturer’s name or logo-type:
— type denomination (e.g. part number):
— input spectral class (or classes) (e.g. EM 1, EM 2 etc.) Followed by the text: according to ISO 7096:2020.
8 Information for use
For information to be provided to the user, the content of this clause, together with ISO 12 100:2010. 6.4. shall apply.
8,2 Test report
The test report shall contain all the information necessary to understand. Interpret and use the results arising from the application of this document.
The results shall be compared with the acceptance criteria for a seat and recorded in the report forms given In Tables 5 and .
The test report should contain the following:
a) name and address of seat manufacturer:
b) model of seat, product and serial number;
c) date of test;
d) details of running-in:
e) type of measuring disc used: semi-rigid, rigid:
1) Input spectral vibration class:
g) vibration transmission to the persons with the simulated input vibration Lest:
— platform vibration awpl2:
— seat disk vibration a.sjz;
— test person mass, In kilograms:
— SEAT factor;
h) calculated transmissibility at the resonance and the resonance frequency;
I) the name of the person responsible for the test;
j) identification of test laboratory:
k) location of marking (see Clause 7).