Conveyor belt restraining in natural hazardous wind events

In preparation for the natural hazardous wind events such as tornados and tropical cyclones, open-air conveyor belts used by Australian mining industry for overland bulk materials transportation are physically restrained by tying them to their structural frames with rigid steel tie-downs over set regular intervals. This study examined a restrained section of a commercial type of conveyor belt focussing on discerning the most accurate approach for optimising the belt restraint interval value. Structural integrity of the belt was analysed with strength of materials, numerical modelling, and aerodynamic methods for a range of airflow angles and for airflow velocities of up to and including category 5 cyclonic events. It was found that strength of materials approach could be used as a rough approximation only, with somewhat fine-tuned results provided by the numerical methods and the conventional aerodynamic techniques. The most accurate results were obtained from introducing dynamic component of the conveyor belt's elasticity into the aerodynamic flexural-torsional flutter treatment of the belt, with this approach delivering an over 30% higher minimal value of the length of the restrained section of the belt at design safety factor of 1.5. This larger restrained section length will lead to a corresponding reduction of the number of belt tie-downs and this, in turn, will translate into strong operational efficiencies while also delivering significant improvements of personnel safety. Additionally, the results of our work improve understanding of the behavior of open-air overland conveyor belts under the irregular aerodynamic loading conditions of natural hazardous wind events.