Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

Force-displacement curve

Hello Sir,

I am working on thin-walled structure. I had got the successful run for the model but the force- displacement curve is not in a way that i wanted it to be. There should be the peak force at the starting and then gradual decrease in force. Please help me .The curve that i want it should be look like the following curve

<?xml version="1.0" encoding="UTF-8"?>

Unable to find an attachment - read this blog

Find more posts tagged with

English

Radioss

Accepted answers

All comments

gopal_rathore

Hi,

This simulation seems to be a quasistatic run which generally takes more time in actual physical condition . You can try increasing the ramp time of displacement(upto 0.2-0.3)

Altair Forum User

Hi CHirag,

It seems like the dynamic effects during the simulation causes for this type of curve. As Gopal suggested try ramping the load gradually on to the model.

Karthic_22061

seems like there are POSSIBLE INCOMPATIBLE KINEMATIC CONDITIONS BETWEEN:
BOUNDARY CONDITION
RIGID WALL

Altair Forum User

Hello Sir,

I don't understand what you want to explain. could you please explain me in details that what should i do to get proper curve?

Altair Forum User

hello Sir

Please help me out.Please explain me.

Altair Forum User

Hi Chirag,

For the imposed displacement load create a smooth and gradual load ramping so that the high dynamic effects can be reduced.

Please go through https://altairuniversity.com/learning-library/7-guidelines-to-apply-quasi-static-load-in-explicit-simulation/ which gives guidelines to quasi static loading in explicit simulations. You can also try using a filter for the curve.

Altair Forum User

Hello Sir,

I had given the imposed displacement to the rigid wall. The times for the curve are 0, 0.045,0.05 and displacements are 0, 135,130. Should i have to use the imposed displacement instead of the imposed velocity? I don't understand that ramping load. Could you explain me please how to get solve this problem?

gopal_rathore

Hi,

You can do foll. change in curve .Impose displacement is fine

0.000000000000 0.000000000000
4.5000000000000E-02 -135.0000000000
5.0000000000000E-02 -130.0000000000

Increase 0.0045 to some 0.3 Higher this lesser will be dynamic effects . Basically we would like the load to reach in slower time to achieve a quasistatic condition

Altair Forum User

hello Sir,

I have the same coordinates for the curve but in prvious run the force displacement curve is not good. Should i have to use the new coordinates as follows

0 0

0.28 -135

0.3 -130

the engine tstop time is 0.05 .Does it need to be change?

gopal_rathore

Hi,

Yes Tstop time will be 0.3 now

Run this and check the F-D curve

Altair Forum User

hello Sir,

I had made changes but this time the the crushing of the middle box did not completed. It has crushed only the starting part may be only 20% of the length.

gopal_rathore

Hi,

Is the time completed or error came?

Share the curve used for imposed displacement

Altair Forum User

Hello Sir

This is the curve that i got. The peak value at the first is nearly only 3500 but through the experimental results i had got it nearly 32000 also the wall does move only 25 mm though the curve defined had value 130. please help me ....

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Hi sir,

What's wrong in my model?

Altair Forum User

hello Sir,

could you suggest me what should i Do?

Altair Forum User

Hello Sir

<?xml version="1.0" encoding="UTF-8"?>