Material Orientation in 2D shell elements: Possible to define 1-direction out of element plane?

Sigfrid

Hi everyone,

 

I need MAT8 material behavior (especially E1 & E2 important) for a curved shell structure, meshed with 2D elements.

In my special case, the material orientation (E1) has to be the direction of the Z-axis of the global coordinate system.

 

2D > composites > material orientation > by system axis > local 3-axis

 

If I define it like that and display the material orientation for the elements, however, the vectors always lie within the element plane and are not parallel to the global Z-axis. 

Is it possible to have a fixed material orientation independent of element orientation (e.g. global Z-axis) for 2D elements? This would mean that the E1 direction would be out of element plane in some cases, as shown by the orange arrows in the figure below. The pink vectors in the example image always lie within the element plane - thats not what I want.

 

Thanks for your input!   

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Rahul Rajan_21763

Refer below video from Altair Learning library for material orientation

https://altairuniversity.com/learning-library/checking-element-normals-and-assigning-material-orientation-using-hypermesh/

Jan Grasmannsdorf_20379

Hello,

as you are using shell elements, the material orientation x-axis (= E1)  is by definition always in the local XY plane of the shells. In your case, you might need to consider a Solid Element model, to have a local E1 orientation in parallel to the z-axis. The material law would then be MAT9 or MAT9ORT.

 

 Jan

Sigfrid

Altair Forum User said:

Hello,

as you are using shell elements, the material orientation x-axis (= E1)  is by definition always in the local XY plane of the shells. In your case, you might need to consider a Solid Element model, to have a local E1 orientation in parallel to the z-axis. The material law would then be MAT9 or MAT9ORT.

 

 Jan

 

Hi Jan,

that confirmes my assumption.

Thanks for the quick reply.

 

Sigfrid

Altair Forum User said:

Refer below video from Altair Learning library for material orientation

https://altairuniversity.com/learning-library/checking-element-normals-and-assigning-material-orientation-using-hypermesh/

 

Hi Rahul,

 

I know in principle how to define material orientation for shell elements and did it exactly like in the video, but E1 is always in element XY-plane (as Jan confirmed in the other reply), which is not what i want.

I will find another way to achieve the task.

 

Thanks for your reply.