Material forces & Implications

Having generated a design for the crane, the issue of material is now at its most relevant as seen above.

I will soon upload the material properties of common materials such as aluminium and steel.

Also the type of rope or line material used is of importance as this ideal needs to be able to withstand over 1000kg whilst in tension. I have done some research on the steel cable design and properties utlising : www.s3i.co.uk.

With varying levels of diameter of cable:

Elastic Stretch = (W x L) / (E x A)

W = Applied Load ( kN )
L = Cable length ( mm )
E = Strand Modulus ( kN/mm2)
A = Area of Cable = (D2 x pi) / 4 (where D= Dia of cable mm)

Typical values for E are:
1x19 = 107.5 kN / mm 2
7x7 = 57.3 kN / mm 2
7x19 = 47.5 kN / mm 2

1x19 Stainless Steel Wire Rope Stronger, with less stretch but also less flexibility than many types of cable. Often used in standing rigging, architectural structural rigging and balustrading. Does not allow for kinks or bends. 7x7 Stainless Steel Wire Rope Less strong but more flexible than 1x19. Used in rigging, balustrade infill and catenary systems. The graph shows typical breaking loads for our hardware compared against conventional 1x19 and Dyform 316 stainless steel cables. It should be noted that stainless steel wire rope and strand will start to distort at around 50% of its breaking load. It is therefore advisable not to load cables to more than 50% of their breaking loads. This is just for steel cables but there are alot more options available for wiring such as aluminium or rope itself eventhough in order to hold the weight, quite a thick rope would have to be used and this may not be suitable for our design as it does need to be able to be transported via range rover! The graph is in the next post.