The nuts, blots, pins and fixings used in this crane would not be made of aluminium as this would cause many problems. Aluminium is too expensive to make small components out of, which means that if any were lost or misplaced (which would be very likely in the chaotic environment of a disaster zone) it would be very expensive to replace them. Also there will be more shear stresses and torsion stresses on these fixings so it is better to air on the side of caution and make them of a stronger metal. Finally the weight of the fixings wouldn't matter as they are only small components, so heavier metals such as steel can be considered.
The majority of readily avalible fixings are made of stainless steel. If the crane was a permanent structure it would be important to state that stainless steel will corrode faster than aluminium alloy and will therefore need replacing frequently. However as the crane is to be put up then taken down for a job at a time, a quick inspection of the fixings before they are used to check for corrosion and spares to replace fixings that are is all that is needed.
No comments:
Post a Comment