Temperature Load on Shell

Grasshopper Karamba3D
1

Hi, I am applying a temperature load to a concrete shell element in addition to a vertical point load in the middle of the element. The shell has four supports on two opposite sides which are restrained in translation in both X, Y and Z. If the support conditions are changed to a simply supported shell element, the deflections remain unchanged despite being free to deform horizontally. Can you provide insight on this behavior?

Thank you,

Mathieu

Karamba 1.3.1
Rhinoceros 6

2

Hi Mathieu,
could you upload the definition or a simplified version?
Best,
Clemens

3

Hi Clemens,
I realized that the maximum displacement from the OptiCroSec component is in the Z direction only as opposed to the maximum displacement from the Analyze component. Also, the fact that the temperature load acts on the entire cross-section of the shell, and thus, at the neutral axis, there will be no added vertical displacement. Those two facts explain why changing the support condition does not influence the displayed displacement. However, when looking at nodal displacements, displacements in both X and Y directions are influenced according to the sign of the temperature differential as expected.

This topic could be deleted, it was just a misunderstanding of component output.

Best,
Mathieu

4

Hi Mathieu,
thanks for your explanation! I think the topic should not be deleted since it can be helpful for others.
Best,
Clemens

5

Hi, I have a question following this problem I don’t quite understand how the thermal load works, In the attached image as you see there is no thermal coefficient attached t the material properties, isn’t this necessary for the analysis?
Also, does the thermal load only affects the geometry cross-section? is it only seen under the shell view displacement results?
Also regarding the shell view result how to spot the following

  • principal forces
  • principal moment
  • shear force in X
  • Shear force in Y
    As I only see principal stress 1 and 2, and Van Mises is not useful with materials like concrete, I was wondering about how to get these results?
    temperature_load.gh (75.6 KB)

image
image1920×1080 263 KB

image
image1920×1080 265 KB

6

Hi,
there are default values entered in the Material Properties so that you can calculate a model even if you do not enter a specific value. If you hover your mouse over you will see that this value is 0.0001.

I do not understand what you mean by the thermal load only affecting the cross section. It affects the entire geometry that you input. You can refer to 3.2.1: General Loads - Karamba3D 2.2.0

You can use the ShellForces component to retrieve all the forces that you require.

7

Thanks Matthew as I understand the thermal load formula Ft = AEa*ΔT Where, we have Cross-Sectional Area, Elastic Modulus, Coefficient of Thermal Expansion, Stress Inducing Temperature, how does this reflect on the thermal load?

8

Hello @lucianatenorio ,
thermal loads induce strains. Corresponding stresses occur only in case the corresponding movements are constrained.
– Clemens