Stiffness matrix

[lucile_riedinger]

Hello, 

I am currently working on a comparision between two floors modelize as shells. For one of them, I create a new thickness with my own stiffness matrix. I would like to compare my matrix with the one Robot make on its own.

Do anyone of you know where I can find the stiffness matrix used by Robot for calculation when you don't create one ?

Thank you very much.

[Rafacascudo]

you can use "orthotropic" type (material orthotropy) , set the thickness , change nothing and then click "display" to show the stiffness matrix.

[lucile_riedinger]

Thank you for your response. But then I do not understand how Robot calculates the coefficient in the stiffness matrix.

For example, I have h = 1.8cm and G = 1080 MPa, Dxyxy = h * G = 19 440 kN but it is not the case : figure attached.

Could you help me to find the formula Robot is using ? The help page named :"Formulas of matrix elements (material orthoropy)" does not explain it for the selection material orthtropy.