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Name: Duane
Status: student
Grade: 9-12
Location: FL 
Country: N/A
Date: 1/4/2006


Question:
A few friends and I were talking about cable length and strength. Our question is: Does the length of chain, cable or rope degrade the overall strength? Longer=stronger? or shorter=stronger? and most importantly, WHY?


Replies:
This is an engineering question.

Generally, a chain, cable, rope, or any long object under stress, will get less strong with increasing length. Not always, but usually.

For any long object under stress, there is always a "weakest link" which fails first. Once the bad link of a chain, or one bad section of rope fails, then the whole thing comes apart.

The longer an object is, the greater the chance of getting a "weak" or "bad" link present. If the factory always made chain links or rope absolutely perfectly, then there would never be any weak links, and length would not matter.

This principle can be applied to other areas as well. For example, a machine with a lot of parts is expected to be less reliable than one with few parts, because chances are that one of those many parts will have a problem.

Bob Erck


Hi Duane

Cable strength is determined by properties of the material out of which the cable is made and the cross-sectional area. Cables come in different configurations of bundles and stranding, but that is done primarily for flexibility. The overall length of a cable really has no bearing on the strength, however, it will affect how much the cable will stretch under a load. If you consider defects that may contribute to premature failure, statistically the longer the cable is, the more likely there will be something that may contribute to failure.

Hope this helps.

Bob Froehlich


As whatever tension you place upon a rope or chain is shared equally down its length, its strength should remain the same whether it is very short or very long.

In practice, it is worth noting that rope and chain both have characteristics of their own. If you suspend something from a great length of chain, the weight of all that extra chain must be added in, reducing your useful load. Also, the longer a piece of rope or chain is, the greater the chance of some imperfection reducing its strength.

Ryan Belscamper



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