ISO 10056:2001 pdf download

ISO 10056:2001 pdf download.Mechanical vibration一Measurement and
analysis of whole-body vibration to which passengers and crew are exposed in railway vehicles.
4.1.2 Contact between wheel and rail
Excitation of a rail vehicle is particularly localized at the wheel-to-rail contact. The rail-wheel contact forces aw iunlinear functions of displacement and velocity and produce vibration in the railway vehicle.
4.1.3 Vehicle
The body of a railway vehicle is a flexible complex structure whose natural vibration can at times be important. Moreover, its behaviour is influenced by its load, by the relative position of the bogies, by the various suspension parts (such as springs, dampers, etc.) and by adjacent vehicles in a train.
Defects in the running surfaces of the wheels (such as flats), and out-of-balance or eccentric wheolsets are sources of periodic vibration, the amplitude and frequency of which are a function of the speed.
Rotating machinery (such as motor compressor sets, diesel engines and air-conditioning equipment) can also create vibration which often also is periodic. Furthermore, acceleration and deceleration (e.g. braking) can excite both periodic and non-periodic vibration.
The non-linear behaviour of certain components (e.g. special dampers, buffers, transverse stops, etc.) can produce transient vibration.
The seat can amplify the vibration and can sometimes add some non-linearities, especially at its resonant frequencies. The response of the seat depends among other things on the way it is fixed, the mass and posture of the occupant of the seat, and the shape and material of the seat itself.
4.2 Nature of vibration Railway vibration signals
are of a random nature, can include periodic features and can cover a wide range of frequencies, but their energy level inside the vehicle is relatively low,
have certain well-defined resonances (e.g. in the vertical direction the vehicle body has a natural frequency on the secondary suspension of about 1 Hz and a natural frequency of bending generally between 8 Hz and 15 Hz),
are not stationary but may be considered as partially stationary, and
– can be permanent (e.g. vibration caused by track irregularities), temporary (e.g. vibration caused by air-
conditioning units) or occasional (e.g. vibration caused by level crossings or turnout).
4.3 Direction of vibration
Generally speaking, at any point of the vehicle, the vibration accelerations are characterized by six components:
three translational components and three rotational components along and around the x-, y- and z-axes, respectively. However, it is assumed that for rotational vibration the distance to the centre of rotation is large enough to consider this vibration as translational.
For more details of measurement of rotational vibration, see ISO 263 1-4.
5 Method of measurement
5.1 General
The physical parameters to be measured are the translational accelerations on the floor and, depending on the aim of the test, at the man-seat interface (and optionally at the man-back interface).
The term “measuring equipment’ used hereafter refers to a set of devices which makes it possible to measure and to record the signals. The signals (whether recorded or In real time) may be subject to further processing which Is described in clause 6.
NOTE In many applications, part of the signal analysis is carried out during the measurement, before the measured signals are recorded. This activity Is called “pre-processing.
In this International Standard “method of measurement” refers to the ways in which the measuring equipment is applied in order to collect the data which are the subject of the tests to be carried out.
5.2 Measuring equipment
5.2.1 General
The measuring equipment normally consists of transducers (accelerometers) and some conditioning amplifiers, filters (band limitation and frequency weighting) and measuring amplifiers, and recorders.
This set of equipment forms a measuring chain.
The characteristics of the equipment should be consistent. The accuracy of the measuring chain is defined by the
characteristics of the individual components as well as by certain characteristics of the complete measuring chain.
5.2.2 Transducers and conditioning amplifiers
Since in many cases it is not possible to separate the transducer and conditioning amplifier, these two devices should be treated together and should meet the following conditions:
minimum measuring range: floor: 0 to 50 ml/s2
man-seat and man-back Interface: 0 to 20 ml/s2
minimum frequency range: 0,4 Hz to 100 Hz (flat to within 0,5 dB);
non-linearity plus hysteresis: 1 % of the measured value;
cross axis sensitivity:
effect of temperature: on zero: 3 % of the measuring range,
on sensitivity: 0,05 % per degree Celsius.
5.2.3 Band-limiting and frequency-weighting filters
To eliminate very-low-frequency as well as too-high-frequency components which are not in the range of vibration relevant to this International Standard, and also to improve the measuring signal-to-noise ratio, band-pass filters should be used.
Lower and upper frequency band limitation shall be achieved by at least two-pole high-pass and low-pass filters, respectively, with Butterworth characteristics, having therefore an asymptotic slope of at least 12 dB per octave. The corner frequencies of the band-limiting filters are one-third octave outside the nominal frequency band.