×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Preload change with temp help

Preload change with temp help

Preload change with temp help

(OP)
This seems like an easy problem but for some reason I have a mental block.

I am trying to model the change in a preloaded assembly as a function of temperature.

The basic situation is this:
A threaded retaining ring is torqued down to get a predefined preload, at room temperature. Then the temperature of the assembly is changed. I want to see how that temperature change affects the preload. What I am struggling with is how to lock the retainer to a reference point or surface. If I don't do that Abaqus will just keep the original load value. I've confirmed this by looking at the reaction force vs. temp and that is a constant value. I don't believe this is what is happening in reality so I am trying to 'fix' it

A simplified problem is this (see image below of axisymmetric case):
I have a fixed housing with a ball bearing placed in it. The ball is held in place using a threaded retainer that contacts the spherical surface. I want to look at how the initial preload changes as a function of temperature.

What I've tried and thought about trying so far:
I have a static step that applies the preload from the retainer then another step that applies the temperature.

What is happening is that when the temperature is changing, and the components are expanding/contracting, Abq is adjusting the retainer position to keep the original preload. That isn't what I want, and doesn't seem realistic. What I'd like is to link the position of the retainer to a point on the housing that in the real part will be part of the thread that the retainer is using. The retainer then would move with that point as the length of the housing is changing.

My first thought was to do a coupling but you can't activate/deactivate for specific steps, the same thing goes for a tie constraint. It doesn't seem like connectors is the right way to go but maybe that is because I just don't have any experience with them.

Any suggestions?

Thanks,
Dan


RE: Preload change with temp help

Is preload deactivated in the second step (the one in which temperature is applied) ?

In order to link movement of the retainer to the selected point you could use equation constraint. Connectors could work too.

RE: Preload change with temp help

(OP)
Yes, the preload is deactivated before the temperature step. I've considered equations too but I need to brush up on them before I can think of how it will be done.

RE: Preload change with temp help

Activate a contact in the second step, that has properties 'No Separation' and Friction=Rough. Make sure that the part is then moved a little bit sideways, so the contact is really closed. Now the part is glued at the contact location.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. Download Now
White Paper - Using Virtualization for IVI and AUTOSAR Consolidation on an ECU
Current approaches used to tackle the complexities of a vehicle’s electrical and electronics (E/E) architecture are both cost prohibitive and lacking in performance. Utilizing virtualization in automotive software architecture provides a better approach. This can be achieved by encapsulating different heterogeneous automotive platforms inside virtual machines running on the same hardware. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close