Ansys wire rope contact definition 1

[ndrssenjaya]

Hi, i'm trying to construct a model of a wire rope that consists of 6 helical strand around core strand and each strand is built from a single core wire and 6 helical wires around. So in total i'll have 49 individual wires that are built into the rope construction (7x7 wire rope). Anybody have the idea how to model the contact between each wires?
I plan to bent the rope to see the effect of the specific bending radius to the maximum breaking load of the rope.

 

[JN89]

since you are bending the wire, it needs to be modeled as a flexible body and you will have to use multibody dynamics for modeling the contacts and flexible bodies at the same time. It also depends on how much transient behavior you want to see. Maybe you can do it with FEA, but not easily. ANSYS doesn't have a good tool for this because you would only be able to look at small sections at a time.

 

[dhengr]

Ndrssenjaya:
The wire rope people have been dealing with (studying) this problem for years in an effort to improve/perfect their product. They have some handle (in good part operating history and years of running experience) on these issues. They have some idea how tight a radius a particular wire rope can tolerate, how this affects its running life, wear/abrasion, crushing, breaking strength, etc. By now, maybe/likely some of this work is FEA based, but I suspect it is a pretty difficult problem to model well. I doubt that they can tell you that wire #36 is the one more likely to fail first, under a given load condition. But, I suspect they can tell you what causes the wear and deterioration of various wires in a strand or the whole rope. I would call a few wire rope manufacturers, talk with their engineering people and see what you can learn about what they are doing. This would make one hell of a sponsored Ph.D. thesis project.

 

[chicopee]

I am not sure where you are going with your OP but I would say don't waste your time to model the contact stress between each wire. Use the recommended industry practices. For example crane and elevator manufacturers will use their appropriate ANSI standards to determine minimum diameter of sheaves in which wire ropes will be running or standing or if reverse bending is expected. ANSI standards are time tested documents which all inspectors in the USA follows plus the fact that there is a certain factor of safety with these wire ropes. Load testing of wire ropes is a better measure of safety than attempting to calculate their theoretical strengths. Furthermore there will be a further reduction in load tests wire ropes when end fittings are included