ISO 5982:2001 Historical

This International Standard describes the range of idealized values of the driving-point mechanical impedance, apparent mass and seat-to-head transmissibility modulus and phase applicable to seated individuals subjected to z-axis sinusoidal or broad-band random vibration under specific experimental conditions. Additionally, a human body model is provided to satisfy the range of idealized values defined for driving-point mechanical impedance/apparent mass and seat-to-head transmissibility. This model is further used to compute values of driving-point mechanical impedance and apparent mass for fixed body masses which are recommended to be used as test loads in current standards defining laboratory seat testing methodologies. Alternatively, mathematical expressions in the form of transfer functions are provided to approximate the weighted mean (target) values defined for all three biodynamic response functions.

The ranges of idealized values defined in this International Standard are considered to be valid for seated subjects supported on a rigid platform, with feet supported and vibrated, and maintaining an erect seated posture without backrest support. Provisionally, the range of idealized seat-to-head transmissiblity values is considered to be applicable also to the condition with the feet hanging freely. The values are defined over the frequency range 0,5 Hz to 20 Hz for subjects within the 49 kg to 93 kg mass range, subjected to sinusoidal or broad-band random vibration of unweighted r.m.s. amplitude lower than or equal to 5 m/s². The frequency and amplitude characteristics of the vibration fall within the range for which most vibration exposure is likely to predominate while driving vehicles such as agricultural tractors, earth-moving machinery and fork-lift trucks. Application to automobiles is at present not covered by this International Standard in view of the lack of a meaningful data base for conditions involving posture and vibration excitation levels most likely associated with car driving.

The upper and lower values of modulus and phase defined at each frequency for each of the three biodynamic response functions considered represent the range of most probable or idealized values. The middle values represent overall weighted means of the human data, and define the target values for general applications. Such applications may involve the development of mechanical analogues for laboratory seat testing, or of functions to correct for the human interface when representing the body as a rigid mass, or the development of analytical human body models to be used for whole-body vibration exposure estimations or for seat and cushion design optimization.

A mathematical representation of the seated human body that falls within the upper and lower limit envelope curves defined for driving-point mechanical impedance/apparent mass and seat-to-head transmissibility is also provided in annex B, while mathematical expressions approximating the weighted mean (target) values for these functions are given in annex C. Model values of driving-point mechanical impedance and apparent mass computed for fixed body masses equal or close to those recommended in specific laboratory seat testing standards are also provided in annex D.