Force Output from enforced Displacement

Timo Ksr

Hi, 

 

I ran a model with enforced displacement with SPCD, as explained here: 

https://altairuniversity.com/learning-library/how-to-apply-enforced-displacements-correctly/

 

Then I requested the force as ouput via Global Output Request --> SPCF

The model was just a regular beam and from beam theory the cumulative sum of the force should be around 824.99 N.

 

In my .out file the force is extremely low and I cannot find the mistake?

 

The model is in tons, mm, second, so the output should be Newtons. 

 

Thanks for your help everyone. 

 

 

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KemalDemir

Can you share please hand. calc. method ? Because you're using enforced disp. I mean your define directly deflect quantity. You have to go backwards and find the strength. Am I wrong ?

Adriano A. Koga

in the .out file you will find only the summation of the SPCF and as you don't have a 'load' it will be zero.

 

Request SPCF in H3D and OPTI formats, and you will be able to check the values in each node.

It would be easier to check if you use a RBE2 for apllying the enforced displacement, and then get a single SPCD reaction value to compare with your expected value.

Timo Ksr

Hi, 

I get better results in a .spcf file now. Thank you. 

 

However, the sum must be close to zero, when only applying an displacement? 

 

For another model, this are the results. I guess the first line is my Loadmatrix at the node? The sum does noe come to zero, is that an indicator for any mistake?

 

 

@KemalDemir I used Bernoulli Beam theory for one fixed end and one free end:   6*E*I*w(x) = F*x^2*(3L-x)

tinh

SPCF are reaction forces, why do you think sum of them is zero?

tinh

Enforced dislpacement equivalences to a set of apply forces NOT only at enforced nodes.

Check .out file for force equilibrium.

Timo Ksr

Now I got it! Thanks