ISO 13753 pdf download.Mechanical vibration and shock — Hand-arm vibration — Method for measuring the vibration transmissibility of resilient materials when loaded by the hand-arm system
1 Scope
This International Standard specifies a procedure to determine the vibration transmissibility of a resilient material when loaded by the hand-arm system. The method is applicable to all materials which behave in a linear way. It is expected that this is realized in most elastic foam and rubber materials and, provisionally, in woven cloths. The method can be applied to mixed systems, e.g. a cloth material attached to a foam or rubber base. It is expected that the results of this laboratory test will be used in screening materials used for vibration attenuation on the handles of tools and for gloves. This will enable rank ordering of materials for gloves, but will not necessarily predict the transmissibility of the gloves fabricated from these materials (for this purpose, see ISO 1 081 9).
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 2041 :1 990, Vibration and shock — Vocabulary . ISO 5349:1 986, Mechanical vibration — Guidelines for the measurement and the assessment of human exposure to hand-transmitted vibration. ISO 5805:1 997, Mechanical vibration and shock — Human exposure — Vocabulary . ISO 1 0068:— 1 ) , Mechanical vibration and shock — Free, mechanical impedance of the human hand-arm system at the driving point .
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 2041 , ISO 5349 and ISO 5805 apply. NOTE For hand-transmitted vibration, see ISO 5805. For transmissibility, see ISO 2041 .
5 Principle
The method uses a vibration excitation system (shaker) on which the resilient material is placed with the loading mass m on the top. Accelerometers measure the vibration on the shaker, a 1 , and the vibration of the mass m, a 2 . The shaker may be driven by a wide-band random signal or a sinusoidal signal.
6 Measuring equipment
6.1 General requirements A frequency analyser (preferably twin-channel), two transducers and two channels of measuring equipment are required. The measuring setup is shown in figure 1 . 6.2 Acceleration transducers and preamplifiers The transducers (accelerometers) and preamplifiers chosen shall be suitable for the frequency range 5 Hz to 1 000 Hz. An overload indication shall be provided. 6.3 Transducer mounting The two transducers shall be rigidly mounted to flat surfaces on the shaker and the loading mass m. The mounting may be achieved using a screw, glue or beeswax. The mounting shall be such that the transfer function between the two transducers is unity up to at least 1 000 Hz without the material sample.
8 Measurement procedure
8.1 Measure simultaneously the accelerations a 1 and a 2 , measured on the shaker and on top of the mass m. 8.2 The shaker may be excited using a wide-band random signal. The power spectral density should be constant within ±1 0 % between 1 0 Hz and 500 Hz with a magnitude of at least 2,5 ¥ 1 0 -2 (m/s 2 ) 2 /Hz. 8.3 Alternatively, the shaker may be excited by sinusoidal signals. The excitation magnitude a 1 should be at least 1 m/s 2 . NOTE The coherence function of the two signals should be measured at each frequency and should be greater than 0,95, although it may fall lower than this value at the resonance frequency. 8.4 Measurement of the ratio A 1 /A 2 shall be performed (in terms of both modulus and phase or in terms of real and imaginary parts) at each frequency. This ratio is a complex function. 8.5 For the purpose of the test report, measurement of transmissibility should be made at the one-third-octave band centre frequencies between 50 Hz and 500 Hz. It is recommended to measure at lower frequencies, down to 1 0 Hz, if possible.