## 1 Investigation of load assumptions |
[German version] |

## 1.5 Rolling factorThe rolling factor was introduced by VDI
Guideline 2700 and " The quasistatic tipping moment on a cargo
unit is calculated from the force F Dynamic tipping moments in the longitudinal or transverse directions arise from the rotational inertia of the cargo mass against the angular acceleration caused by pitching or rolling oscillations. These give rise to a "dynamic" turning moment on the cargo unit in question which is independent of the location of the tipping axis and center of gravity of the unit (Figure 7 right). The following applies to the magnitude of this additional moment: Transverse direction :
For homogeneous or hollow cubical cargo units, the moment of rotational inertia J about an axis through the center of gravity may be approximately determined by:
Figure 7: Static and dynamic tipping moment The applicable VDI Guideline 2700, Sheet 2 requires an allowance of 0.2 g for securing cargo units at risk of tipping on the assumption of sideways acceleration of 0.5 g. The rolling factor is explicitly not used for testing and dimensioning the securing against sliding of these cargo units at risk of tipping. In order to verify the reasonableness of the order of magnitude of this rolling factor, the rotational inertia of a cargo unit at risk of tipping (h ³ 2 × b) of maximum height (road transport: h = 3 m) is converted into an allowance w for transverse acceleration. Figure 8: Conversion of a rotational tipping moment into a rolling factor Tipping moment from rotational inertia: Equivalent tipping moment: Acceleration allowance, homogeneous: Acceleration allowance, hollow: The angular acceleration from rolling oscillations or pitching oscillations to be used may be estimated from the described simulation calculations. Since these simulations may all be considered borderline situations, the results are usable for the stated purpose. Full braking, cornering and lane changing
exhibit maximum angular acceleration values of 0.5 s If generous angular accelerations of up
to 1 s Figure 9: Angular acceleration values for pitching or rolling oscillations For securing unstable cargo units against tipping, the relatively recent draft of DIN EN 12195-1 (01/2009) only requires 0.6 g to be assumed as transverse acceleration, i.e. an allowance of 0.1 g. An equivalent pitching factor does not apply in the longitudinal direction of the vehicle. The conclusion which may be drawn from the above considerations is as follows: It is possible to support the assumption of 0.1 g as a reasonable acceleration allowance for securing cargo units at risk of tipping against tipping. The allowance should, however, also be used for securing such cargo units against tipping in the longitudinal direction. |

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