Snap fit hook optimization

[ghorvath]

Hi fellows,

I want to make a structural analysis for the snap fit hooks. I found a very useful video on the ptc page:

http://learningexchange.ptc.com/tutorial/3547/defining-contact-faces-with-finite-friction

Could anybody share with me this files? The video doesn't contain detailed description...

Regards: Gyorgy

[DenisJaunin]

Hello, Gyorgy,

This example is very interesting and I would be interested to share these files.

Best regards.

Denis.

[TomD.inPDX]

You could try contacting customer support to see if they can hook you up. I suspect these are in the PTC university collection.

[ghorvath]

Thanks guys, I will send to PTC an e-mail about this. I hope they will share with me this fine analysis.

Regards: Gyorgy

[mfischer]

Hi Gyorgy,

Thanks for your interest in this new capability in Creo 3.0. Sadly the model I used is a customer model and I cannot share it. However, I am currently creating a new sample model which I would be happy to provide.

Still wrapping it up and running a test.....should be available shortly.

Please send me an email (-) and I can send you the files.

Thanks,

Mark

[mfischer]

Hi Gyorgy,

I have attached a sample model you can test.

Note: It was created in Creo 3.0 with the result files.

Give it a try and let me know your thoughts.

Video Link : 5207

Thanks,

Mark

[346gnu]

Mark,

A couple a questions.

What was the state of the 'press fit' (initial interpenetration)' check box in the defnition dialogue?

How did you choose your time step?

Thanks

Charles

[mfischer]

Hi Charles,

I have created a series of contact interfaces with finite friction in the assembly to control how the parts interact with one another. Once you assign a contact interface, the Press Fit check box will be automatically checked. I kept the default value of 0 mm for the initial interpenetration.

I ran the analysis at a variety of steps to: 11, 21, 31, 61. The higher the step number will reduce the size of each step when spaced equally. The smaller time step will help provide a more accurate convergence of the nonlinear solution. However this will yield longer solving time.

Thanks,

Mark

[346gnu]

Mark,

The reason for the question re steps is that poor selection can cause the parts to miss each other as the actual point contact occurs can lie between time steps.

Combining this 'missing' of the contact with the initial interference check box state has caused me some counter intuitive experiences,

Next time I have one I'll pass it across if I can.

Thanks

Charles

[mfischer]

Hi Charles,

Good point and I have seen that as well from time to time. I tend to run a number of tests with different steps to determine the best method. In fact the analysis will give you a reminder to reduce the step time to gain improved accuracy.

If you come across example on counter intuitive experience....would like to see it.

Thanks

Mark

[DenisJaunin]

Hello, Mark,

Thank you for your.

This seems quite complex to me.

I just followed a Webinar PTC:

Using PTC Creo to Optimize Product Designs -.

It is a demonstration of the closure of the box or the battery is housed for the helicopter.

It is a system with a clip, very interesting but far too fast, can not see how it's done.

Would you have the opportunity to get this demonstration.

Best regards.

Denis

[mfischer]

Hi Denis,

To assist you with the setup process, I have created a walk through video tutorial. I have also attached a sample model used in the video which you can go through. The zip file contains the final model and the start assembly.

Video Link : 5213

Thanks,

Mark

[DenisJaunin]

Hello, Mark,

Thank you for sending this message.

It's just that I will look carefully at this demonstration.

Best regards.

Denis.

[DenisJaunin]

Hello, Mark,

Again thank you for your demonstration.

I want to say that I am very fond of PTC since version 13 and Rasna DOS.

Is there an automatic way to detect contacts on the same part and set once the coefficient of friction?

The selection of faces that will be in contact is not easy, it seems that some may not match required. (B3)?

Why there are no restrictions on geometry when you cut the part, it's because of the "Solidify" function?.

The computing time should be about 2 hours long?.

I looked at some other software, but I do not know exactly how it defines their implementation.

Best regards.

Denis.

http://www.comsol.com/search/?s=hook&subset=model_gallery

[mfischer]

Hi Denis.

I Suggest we get on a call next week to discuss. Please send me an email at -.

We can work through your questions. It would be easier to share my screen and go through the process.

Thanks,

mark

[346gnu]

Mark,

The other question I meant to ask is methods of managing the 'falling off the edge' when the clip snaps into place. Three things noted from previous work we've done, time steps need to be very fine here, all the contacts change around, best have rounded corners so that changes are gradual not abrupt.

Any thoughts?

(as a slight hijack of the thread, can we have optional automatically created contact force components? In WCS would do. If we have 200 contacts then it is a tedious error prone measure creation exercise. Contact components help us QA).

Thanks

Charles

[mfischer]

Hi Charles,

Drop me an email at - and we can setup a time to talk live.

Thanks,

Mark

[mfischer · Accepted solution]

Hi all,

Here is another example of the new Contact Interface with Finite Friction in Creo Simulate 3.0. Thank you Urs Simmler for creating this example.

Video Link : 5231

Regards,

Mark

[DenisJaunin]

Hello, Mark, Urs,

Meri you for this very interesting example.

Best regards.

Denis.

http://www.amazon.fr/Caract%C3%A9ristiques-m%C3%A9caniques-clips-CETIM/dp/2854008286

[DenisJaunin]

Hello Mark,

Is it possible to output a HTML report with the full simulation.

Best regards.

Denis.

[mfischer]

Hi Denis,

Creo Simulate Results offers the ability to output report to HTML. You can include a source of information, including: animation, images, measures, etc.

Attached is a sample HTML report.

Thanks,

Mark

[DenisJaunin]

Hello, Mark,

Thank you for that very comprehensive feedback.

I would not abuse your kindness, but on the video we see at the same time a graph of the change in force, this little graphic to be directly visible at the same time as the web feed, or if it is a video editing.

With thanks.

Denis.

[mfischer]

Hi Denis,

Sadly, the syncing of the simulation was done post video output from Creo Simulate.

The output points for the graph can easily be outputted from the results.

After a little editing we put the two together and provided the final video.

I am looking to improve the graphing in a future release to help product similar video our of Simulate.

Thanks,

Mark

[gkoch]

I set this post as Correct Answer to mark the Thread as Answered, although the thread contains quite some more interesting posts and different questions.