Bolt modelling 2

[opethian]

Hi to all,
Nowadays we are trying to model bolts by using beams instead of solid modelling them. My question is how can i apply pretension force to the beam element in abaqus or in hypermesh ? do you have any opinions about bolt modeling with beam elements and pre tension. I wanna to find an easy way to model bolts with pretension cause ? have a lot of bolts in my assemblies all the time. So it will be time saving and reduces the cost of the simulation.

 

[gurmeet2003]

opethian,

I tried to apply a bolt load on a 1_D beam or truss. I could not find a way to do the same. It appears that the bolt load can only be applied to a 3D bolt, at least in Abaqus CAE module.

Gurmeet

 

[jamedorr]

Define a coefficent of thermal expansion for the material of the fastener beam.

Then define an initial temperature that is greater than the temperature you apply in the first step.

I usually apply loads / additional boundary conditions in a second step.

You can use the first step to see the actual clampup values, which will require some tuning by varing your temperature, because the stiffness of the your stack being clamped can only be estimated.

I used this method for solid 3-d bolt modeling, and it should work (much more efficently) with a beam element.

 

[opethian]

Thanks for your valuable ideas about bolt modeling. I keep trying those modeling ways. so it seems that the only way to model the bolt is 3-D modeling. If there is a way to model the bolts with beam elements can you send me details about it.

 

[gurmeet2003]

I think there may not be too much advantage in using a beam. If you are interested in only simulating stiffness of the bolts. You could simplify the shape to cylinderical and use a course mesh. Also if you have a large number of bolts in your model. You could omit some and model bolts in your specific area of interest.

Gurmeet

 

[MrMyers]

I remember making a model a few years back using beam elements as bolts in 3D space.

Make a partition half way along your beam element bolt and use the *Pre-tension section, keyword (probably can use CAE for this too).

Any luck?