AS 5714:2015 pdf free download – Load restraint for LP Gas cylinder distribution

AS 5714:2015 pdf free download – Load restraint for LP Gas cylinder distribution.
1.5.4 Cylinders being thrown vertically
Legislation in Australia allows rear overhang to be a maximum of 3.7 m or 60% of the wheel base.
When designing and specifting LP (las cylinder delivery vehicles, minimization of the rear overhang as a percentage of the wheel base shall he a primary consideration.
The two situations illustrated in Figure 1.4 show the differing effects when the front and rear axles go over a speed bump.
Where the steer axle goes over a speed bump so that the tyres and suspension are compressed, the front of the truck is driven upwards. Generally, drivers ill drive at a speed that will avoid being propelled out of their seat and in this case the upward acceleration will he less than 1.0g.
In contrast, when the rear axle goes over the same hump the Situation IS very different. In this case, the upwards acceleration of the drive axle is increased by up to 60% at the rear of the tray. The upward acceleration of 0.4g to 0.6g will become 0.4g x 160% to 0.6g x 160%, i.e. 0.64g to 0.96g. This is on the verge of propelling the cylinders at the rear into the air.
The photograph in Figure 1 .5 illustrates cylinder dislodgement where the upwards ‘g’ force at the rear has been excessive.
2.3.4 Loss of cylinders through central support failure
For the cylinder truck design concept being covered in this Clause, 50% of side forces are resisted by the central support. The maximum length of the LP Gas storage space is 8.4 m; therefore, the central support shall resist the LP Gas cylinder-related forces with a safety factor of 2.5. These forces are—
(a) a shear force of 18. 500 N; and
(b) a bending moment force of 2, 510 Nm.
2.3.5 Other detailed design considerations to minimize the risk of failure
Where there is a sudden change in shape of a structural member, stress concentration will occur. The safety factor may be increased.
A weld joint shall be designed so forces are transferred through welds in shear. It is poor welding practice and not recommended that a weld be in pure tension.
For example, using rectangular hollow section (RHS) steel tubes for the central support for the headboard uprights, butt welding these against the top of the ceaming rail and welding around the point of contact is not recommended. The minimum material that will resist the forces and provide the required safety margins is a 100 mm x 50 mm x 4 mm RHS tube with the 50 mm dimension lined up with the 50 mm width of the coaming rail.
The method in which this support is attached to the coaming rail is critical. The
100 mm x 50 mm x 4 mm REIS lube shall not be butted to the coaming rail and welded
around its circumference. Any internal weld defect may crack and fail as maximum loads
(tension plus shear plus bending moment) are applied to that weld.
Plates, angles or other devices shall be used to ensure that the welds resisting failure are not in tension.
Two possible arrangements are shown in Figure 2.2. with all edges and corners smoothed and rounded. Other detailed designs that achieve the same result may be used.