Inventor NASTRAN Analysis Problem

[LastFX]

Hello to everyone...

First of all my english is bad, sorry for that...

I'm working on Explicit analysis but having a problem. I simply want two objects to collide. But the collision is not happening they go through each other. The two objects are not touching each other.. 

what is the problem ? 

[John_Holtz]

Hi @LastFX . Your English is good! Even though English is my native language, my typing usually has some mistakes which can make it hard to understand. 😁

I do not see any contact defined in the model tree. Contact tells the software how parts are connected together, whether bonded (such as parts welded together) or separation (as in your case: there is no contact until the gap between the parts is reduced to 0. Then a compressive force is transmitted between the parts.)

Please use the "Contact > Manual" and select the faces of the two parts that will come into contact. 

After you add the contact and run the analysis, the next issue is whether the deformed view is showing the real displacement (0.066 whatever the units are), or is it exaggerating the displacement so that some deformation or motion is visible. I do not remember what the explicit analysis defaults to. You may need to edit the contour and set the "Deform Options > Scale" to "Actual" to see the real displacement without any exaggeration.

[LastFX]

I used surface contacts as you said.I chose the primary surface box. the secondary surface is aluminum.

contact type : seperated.

but the result has not changed 🙂 I don't understand what am I doing wrong 😞

Can you edit and upload if I add it here? (I attacted file)

[John_Holtz · Accepted solution]

Hi @LastFX 

Your parts are separated by 1.355 inches. With a velocity of 500 in/sec, it will take 27E-4 seconds until contact occurs. Since your analysis is only at 3E-4 seconds, you have to run the analysis for a lot longer. In other words, the parts are still far apart! (As indicated by the 0.15 inch displacement in the label in the bottom left corner if the image.)

27E-4 seconds duration to wait for the contact to occur is like an eternity in an explicit analysis. (Unless you are only interested in the rigid-body motion, your mesh will need to be much, much finer. The analysis is not going to run in seconds when you have the proper size mesh.) You should consider moving the parts closer together. You only need a few time steps before the moment of impact. Since the time step size is 1.45E-7, the separation could be as small as 1.45E-7 sec/step * 100 time steps * 500 in/sec = 0.007 inch.

[LastFX]

OMG ! 

Yes my problem is really solved. Thank you so much 🙂
I'm very new to Inventor. I never thought this was the problem.

Here is the happy ending. The collision took place. 🙂