Trouble with "utilization"

Hey everyone,

I have two questions about the karamba component "shell view":

First:

It gives me negative utization values. I would like to have just absolute values.

Does anyone have an idea how can I deal with that?

I thought about going over the karamba component "utilization" where I could change to the absolute vaules. That might be a solution, however it would mean to rewrite the component from shell view.

Second:

The karamba component "shell view" doesn't gives me the maximum values, but just an approximation like this:

Is it possible to change that?

All the best

Jakob

Replies to This Discussion

Permalink Reply by Karamba3D on June 27, 2016 at 12:03am

Hi Jakob,

For beams a negative utilization - calculated as yield stress divided by normal stress - indicates compression. For shells the utilization is calculated as the ratio between the yield stress and the Von Mises Stress and is always positive. Do you have beams and shells mixed in your definition?

In the ModelView-component, submenue 'Render Settings' you can set the upper and lower threshold for the results display. When '% of range' is enabled, 'Upper Result Threshold' should be '100' and 'Lower Result Threshold' shouldbe '0' to display the full range of results.

Best,

Clemens

Permalink Reply by Shasan Chokshi on March 11, 2020 at 8:52am

Hello,

I read your reply and is quiet helpful. I am working on a grid geometry as shown in the image where all the members are beams. I have applied the yield strength of material as 6KN/cm2 (because of wood material) which is 60 MPa as shown in image. when I divide the stress with yield strength, the results are little less than than the results I get from utilization output. If the component uses the axial stress/yield strength, why the values are different in both the cases? How does it the component calculates utilization output for such continuous beam structure?

Thanks,

Shasan Choksi

Permalink Reply by Karamba3D on March 11, 2020 at 2:17pm

Dear Shasan Choksi,

the utilization-component returns the utilization of the cross section as a whole according to EC3 which includes the interaction of normal forces, shear, bending, lateral torsional buckling and stability under compressive normal forces (see https://manual.karamba3d.com/3-in-depth-component-reference/3.6-res...). The ratio of the extreme value of normal stress to material strength does not take into account these effects.

Best,

Clemens

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