ISO 16333 pdf download – Heavy commercial vehicles and buses —Steady-state rollover threshold- Tilt-table test method

ISO 16333 pdf download – Heavy commercial vehicles and buses —Steady-state rollover threshold- Tilt-table test method.
3.3
roll unit
essentially self-supporting combination of roll-coupled vehicle units, the combnation being free to roll independentty of other units
NOTE Typcally. vehicle siits joined by IWth-wheel coiclings (which provide roll coupling) belong 10 the same roll unit. while vehide units joined by pintie hitches (which do not provide roll coupling) belong to different roll units. Roe units including converter dollies codd require minor vertical support at the drewter pintle hitch.
3.4
steady-state rollover threshold
maximum magnitude of lateral acceleration that a vehicle can sustain dunng steady-state cornering on a flat surface without rolling over
3.5
tilt angle
#1
angle between the horizontal and a vector that is in the plane of the tilt-table surface and Is perpendicular to the tilt axis
3.6
tilt-table
apparatus for supporting a vehicle on its tyres on a nominally planar surface and for tilling the vehicle in roll by tilting that surface about an axis nominally parallel to the X-axis of the vehIcle
NOTE A tilt-table can be composed either of a single structure supporting all tyree of the vehicle on a contiguous surface or 01 mufliple structures supporting one or more axles on separate, but nominally coplanar, surfaces.
3.7
tilt-table ratio
lan (#y3. i.e. tan($), at the occurrence of critical wheel lift
3.8
trip rail
rail or kerb fixed to the tilt-table surface and oriented longitudinally beside the low-side lyre(s) in order to prevent the tyre(s) from sliding sideways
3.9
wheel lift of the P1 axle
‘WI
condition in which either all left or all right tyres of the e axle are out of contact with the surface of the tilt-table NOTE It Is a logical variable with values of 1 (true) or 0 (false).
4 Principle
The tilt-table test is a physical simulation of the roll-plane behaviour of a vehicle In a quasi-steady-stale tum of gradually inceasAng severity. In this test, the vehicle is mounted on a tilt-table with the vehicle’s longitudinal axis located parallel to an axis about which the table can be tilted. The tilt-table is then gradualy tilted up to the point at which the vehicle becomes unstable in rot Safely restraints are used to prevent the actual rollover of the vehicle.
When the table is at a non-zero tilt angle. the test simulates a non-vibratory steady tum. As shown in Figure 1. the component of gravitational forces parallel to the table surface provides a simulation of the centrifugal forces experienced by a vehicle in turning manoeuvres. The progressive application of these forces by slowly tilting the table serves to simulate the effects of Quasi-statically increasing Lateral acceleration in steady turning manoeuvres.
The tilt-table test is a quasi-static test so that data pmcessing concerns relating the natural frequencies of vehicle responses and the frequency response of the wistrument system do not apply in the usual manner However, the banctwidths of the analog data systems and the sampling rates of digitising systems, in relationship to the maximum tilt rate of the table and the rnaxwnurn ml rates of the velucle and its components. influence the overal accvacy ci the measurement system. Specthcations should be in accordance with ISO 15037-2. In any case, the time response and latenoes of all analog and digital elements of the measurement system shall be property considered in evaluating measureinent accuracy.
7 Test conditions
7.1 General
Limits and specificalions for the tilt-table, embient conditions and vohiclo lost conditions indicated below shall
be maintained during the test. Any deviations shall be reported In the test report
7.2 Tilt-table properties
The tilt-table facility shall have the properties given in Table 2. In addition, the tilt-table facility shall provxte lateral constraint of the vetiide through adequate surface friction or, optionally, through the use of a trip rail, as specified in 8.1.2.