Cable's fatigue

[mosab2]

Dear all,

How can i calculate the fatigue of a cable (a lot of fibres) of composite material?

Is it possible to simulate it by Abaqus?

Thank you

 

[Twoballcane]

Do you know how to do a fatigue analysis? If you do all you need is the stress (or reversal stress)from FEM.

Tobalcane
"If you avoid failure, you also avoid success."

 

[mosab2]

Dear Twoballcane:

I know how to do the fatigue analysis in metal material using the Goodman diagram, but I don´t know do it in metal material cable.
I don´t know how to do the fatigue analysis in composite material, so please if you know how, can you send me something like a note explianing me how I can do it?

Thank you.

 

[rb1957]

do you have an s/n curve for your material ?

 

[ESPcomposites]

Mosab,

I think what is trying to be said here is that you may approach the problem as if it were metallic. In other words, you would get the loads from the FEM and do a fatigue analysis via classical solution (outside of the FEM). In that sense, what you do in the FEM does not change just because the material did.

Now, on the other hand, if you asking the seemingly more important question of how to do fatigue analysis of a composite, you would not want to ask that in the finite element forum.

Brian

http://www.espcomposites.com

 

[rb1957]

does the goodman diagram apply to composites ?

what composite ? graphite, glass, rope ?

 

[mosab2]

Dear rb1957:

I have the S/N curve, my material is: Kevlar.

to analysis this problem by FEM:
1- I have to simulate the cable as a rod with a lot of wire beside? or just a rod with the Kevlar property?
2- I have to simulate the contact between the wires?

When I have the stress by FEM, I have to estimate the material life as the classical way?

Thank you.

 

[rb1957]

i'd model as a rod, but i think there's a 2ndry effect if the fibers are twisted together ?

contact ? aren't the fiber cured in a matrix of resin ? the resin will shear the load into the fibers, no?

sure, miner's rule is probably as good as any. remember there's probably be a static tension in the cable.

 

[GregLocock]

Can I ask roughly how many cycles you are expecting?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[rb1957]

and what'd be driving the fatigue (what's the cyclic load) ?

 

[btrueblood]

The working life of cable is not driven solely by fatigue, but also by the fretting/scuffing damage due to motion of the strands against one another during flexure and axial cyclic loads, and due to the radial distortions when wound over pulleys.

 

[mosab2]

Dear rb1957,
The cyclic load here is the weight (0 to weight).
But as btrueblood said, there is a fretting damage.
I think that i will simulate 3D rod and i will have the stress by abaqus, after that i will try to calculate the life.

I hope that i can do it.

Thank you