Pair Nodes that are in contact automatically. 2

[ariyannn]

Hi,

I am predicting wear depth in Abaqus using Python scripts.

I need to find all the nodes in contact for one part, and find the closest node on the alternative part to pair them. For instance if we have node No. 100 on part 1 in contact, I want to pair that with the closest node on the other part which is in contact, say node No.200 on part 2. The out put requested should be (100, 200). Is there any way to find the nodes in contact and pair them automatically, either in Abaqus CAE or a python code?

Currently, I am working on an axisymmetric model with coarse mesh and pair them manually. I have got only 20 pair nodes right now and it is possible to pair them manually. however, for a 3D model with a refined mesh, it is difficult to find the nodes Number in contact for 2 parts and Pair them.

Any suggestions would be greatly and gratefully appreciated.

Ariyan

 

[isyhadh]

can you please contact me at
isyhadh82@gmail.com
i'm based at london, doing the same and related area like you

 

[IceBreakerSours]

Read this thesis.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[ariyannn]

Hi there (IceBreakerSours)

your attached thesis should be very useful. I've been going though that, however, could not figure it out yet.

BTW, many many thanks for your post.

 

[IceBreakerSours]

If you look up the thesis supervisor's work (thesis, papers, etc.), you will gain a better understanding. However, if you are not familiar with subroutines, beware that coding can be a non-trivial task.

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[MechIrl]

Do you need the results to be available during the analysis or just for post-processing of results? If its the latter then life will be a lot easier. You could for example create a set of nodes expected to come into contact on each part, then in the ODB loop through the nodes of one of the sets and for all nodes in contact in that set identify the closest node that is in contact in the second set. You could use CSTATUS to check if nodes are in contact.

 

[ariyannn]

What I need, is only the node numbers in contact and find the closest node to pair them.

In case, I need a Python code to:

first- extract the node numbers in contact.

Second- pair them with the closest node on the alternative part in contact.

I have written a python program to calculate wear. I provided the pair nodes manually. I am not familiar with subroutine and don't know how can I apply them. but if I can find any way even in Abaqus CAE, I will be able to develop my script to a program that can mesh the model, find the contact surfaces, find the nodes on contact surfaces and finally pair them in order to do calculation on the results of each pair nodes.

I've read in Abaqus manual about the UMESHMOTION, but I don't know how I can involve that in my Python script.

 

[MechIrl]

UMESHMOTION is for use during an analysis with ALE adaptive meshing. It isn't really of any use in a python script. I think I misunderstood what you were trying to do in my last post. It seems what you are doing is all pre-proccesing to generate a model?

In this case I guess you need some criteria for finding nodes 'in contact'. You could manually inspect the nodes and add ones you think should be in contact to a set or define a minimum normal distance between the node and an opposite face or run a dummy analysis and use the CSTATUS identifier to get contact nodes.

Pairing them with nodes on the other surface is simply a case of looping through the set of nodes in contact on one part and identifying its closest node on the other part.

 

[ariyannn]

Thanks, CSTATUS is not available as a filed output for dynamic explicit analysis and as you mentioned the UMESHMOTION is not applicable.

I found a way to do that.

First, we need to extract the total nodes from the input file for both parts. Then loop around all the nodes for a part to check weather the contact pressure is available or not. If the contact pressure is available, save the node label in a repository. Do that for the 2nd part as well and save in an alternative repository.

Afterwards, for all the nodes in contact saved in an array, we can extract the coordinates of them from input file and loop to calculate the minimum distance.

If you need to do that contact me to explain further for you.

ariyan.ashkanfar@gmail.com