# Elvis

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Beginner

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• Are you University user?
Yes
1. ## SPCF-Problem

Hi Prakash, ok thanks. I am looking forward to your information.
2. ## SPCF-Problem

I did a simulation with a displacement of 100m also and compared the graphs in one plot. As you can see, the graph history is almost the same, but with different values. Why is the SPC-Force dependent to the total displacement? Does that make sense?
3. ## SPCF-Problem

Hey, I try to simulate a large displacement movement and have a problem. I got two simulations and want to evaluate the SPC-Forces, which are completely different, although the model is the same. The constraint is placed in the middle of the green component and connected to it, with rigids (see Figure). In the first simulation, the total displacement of the green component is 350mm (due to constraint) in x-direction. In the second simulation the total displacement is 50mm. When I evaluate the force-displacement plots and compare them, the results are completely different, which makes no sense. For example, in the first model the force at 50mm displacement is 6,7e+05 N. But for the second model, the force at 50mm is only 8,19e+04 N. But they should be totally the same to my opinion. Somebody any hints? Greets Elvis
4. ## four-point bending test

Hey Prakash, I sent you the informations again. Thanks.
5. ## four-point bending test

Hey Prakash, I sent you the model file and the data sheets a few days ago. Did you check it already?
6. ## four-point bending test

Hey Prakash, yes the force is applied in Newtons (450N in total), the engineering constants in MPa.
7. ## four-point bending test

Hallo, for the validation of my model I tried to simulate a four-point bending test with a sandwich panel. The layers are modeled with MAT1-Material and the core with MAT9ORT. Somehow, the results are not matching to the one on the testing machine of the sandwich part, which I got from a data sheet. The displacement should be about 1,5mm, but I got 18mm. I attached my matieral card and a screenshot of the model. The engineering constants were provided from the supplier. They should be right because he sent me screenshots of his simulation, where he has a displacement of about 1mm.
8. ## Contact Penetration

Ok thanks Prakash. Another issue. I want to determine the reaction forces at the constraint which is performing the displacement, but it somehow don't show me any results. I activated the GPFORCE button and then tried to show the reaction forces in Hyperview with the option "derived results", that's how I did it in previous tasks. But I do not get any result with this. The model which you sent me ("PinLug.fem") has the same problem. Any hints?
9. ## Contact Penetration

No I did not change anything. There were no convergence issues. When I change the animation button to "transient animation" I get the right deformation as well.
10. ## Contact Penetration

Prakash, I found the mistake. I did not use NLOUT, and when I started the animation I saw this result which I sent you above. Using NLOUT and then switching from Load factor to Load factor in Hyperview is showing me the right deformation, without seperating of the components. This result is satisfying, but I don't understand it. Why is the result dependent of the animation option?
11. ## Contact Penetration

Done . And no, there are no shell elements in the model.
12. ## Contact Penetration

It's similar to the previous one. I activated Large Displacements as well.
13. ## Contact Penetration

Hey Prakash, thanks, you really helped me a lot. I didn't know that the function LGDisp is existing. I am working on a updated model which is not so stiff and where the calculation is executed much faster. I used the same settings like you, but i got some strange deformations here. As you can see, the contact is working very well at the beginning, but in the middle of the motion the components are seperating, which should not happen. Do you know what could be wrong?
14. ## Contact Penetration

Thank you Prakash, you helped me a lot. But what is the problem with the above mentioned model? The contact is failing here at the beginning already. The deformation is totally unrealistic.
15. ## Contact Penetration

Hey Prakash, yes I know, I have the same problem too. I updated the model, because I thought it was to stiff maybe, but the contact is working incorrect from the beginning now. I tried to change the SRCHDIS and CLEARANCE Parameters, but don't get good results either. I just want to understand the contact behaviour in Optistruct, but it's totally confusing to me now. Maybe you know what the problem with this model is? I attached the .hm and the .h3d files for you. pin_lug_update.hm pin_lug_update.h3d
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