To obtain a force in an element using shell-membrane force.

[smirnov.da]

Hello!

I want to get force in the part of model for carrying out tests. I want to get force in the part of model for carrying out tests. I show, how i want get force on a simple models.

In this model load is F=1000N, E=2e+5MPa, mesh - 0,01 m.

Bottom is shouwn shell-membrane fx diagram.

I can get force in the each shell-element. Method is here https://knowledge.autodesk.com/support/inventor-nastran/troubleshooting/caas/sfdcarticles/sfdcarticl....

Taking all these results together on each one gorisontal row give values to ~1000N.

Сonsider a more complex model.

The model contains 3 elements. Central element has E = 2e+5 MPa, side elements have E = 25000 Pa. Mesh - 5 mm.

Bottom is shouwn shell-membrane fx diagram.

I get the following: The sum of the series of all elements of the same level is lower than the load values.

rows of elements

Where does part of the load go?

[John_Holtz]

Hi @smirnov.da 

How did you get the values in the graph? Those values (-1, -1.5, and around -3.5) do not agree with the contour plot (-7 in the center, -2 on the side plates).

Also, the membrane results are N/mm, so you need to integrate over the width of each element to get the total force.

You might want to put the three plates into separate parts and create an assembly so that you can hide two parts while probing the results of the third part.

Let us know what you find out.

[smirnov.da]

Hello John!

Thanks for your response. 

The values ​ ​ for the central plate are different - there are -7 and -2.6 and -4.7. But this is not the main thing.

Central plate shown below.

I think that with this loading and fixing mode, the sum of all elements at one level should be approximately equal to the applied load. As I have shown before. The force in one mesh element is equal to N/mm * mesh size. The following are results by level. The sum of the force does not match the load.

Level elements shown below.

Results of level

Also, the sum of the lower level forces does not coincide with SPS Summation. Same with the top level.

Lower level.

Results of lower level.

I am interested in the followingl for multilayer assemblies : why there are differences level force,calculated using shell membrane force, and applied load? Since it is on a simple model.