5  Summary, outlook and objectives

5.2  Rolling factor

In this context, the rolling factor of 0.2 g set out in VDI Guidelines 2700, Sheet 2 was also investigated, which has previously been intended for use as an allowance for addition to the assumed transverse acceleration of 0.5 g for securing cargo units which are not inherently stable against tipping. It is correct that such an allowance is necessary due to the rotational inertia of units, since the turning moment to be derived there from is not covered by the conventional tipping moment composed of transverse force and lever relative to tipping axis. However, at 0.2 g, the allowance is set too high. An allowance of 0.1 g, as stated in the 2009 draft standard DIN EN 12195-1, would seem entirely adequate. Moreover, a corresponding allowance should also be used for cargo units which are at risk of tipping in the longitudinal direction of the vehicle.

If, including the allowance of 0.1 g, the stableness of a cargo unit is ensured by the inherent stableness, a tipping balance need not be calculated. Further investigations should, however, be carried out to clarify the extent to which this test for inherent stableness should take the actual moment of rotational inertia of the cargo unit and the decrease in normal force into account.