1D mesh stresses

Altair Forum User

Hello,

 

I would like to mesh lines with 1D elements, with a tubular cross section. I used a CROD element, so I could define the cross section, but after calculation the displacement seem too small, and the stresses are not displayed.

Can you please suggest me an element type that is proper for tube meshing?

 

Thanks:

Sanyo

Altair Forum User

HI Sanyo,

 

Since you said you are having a tubular section, use CBAR or CBEAM, instead.

Altair Forum User

To output the stress for the beam elements we need to need to specify the Stress Recovery Coefficients C1, C2, D1, D2, E1, E2, F1, F2 (4 points on the X-section) on the beam property card. 

C1, C2 (or D1, D2 ...) are the y and z coordinates in the BEAM element co-ordinate system of a point at which stresses are calculated. See the attached powerpoint for the visualization of this. For e.g if you need to calculate the stresses on the surface for the tubular x-section you could use the following values based on the outer diameter of the tube you are using: 

C1, C2 = 0.025, 0.000 
D1, D2 = 0.000, 0.025 
E1, E2 = -0.025, 0.000 
F1, F2 = 0.000, -0.025 

This is just an example, you can use any other coordinates. 

Now moving to HyperView post-processing the stresses you can contour are the following: 

CBAR/CBEAM Long. Stress SAC - The longitudnal (extensional) stress at end A for point C. positive values means tension, negative values means compression. 
CBAR/CBEAM Long. Stress SAD - The longitudnal (extensional) stress at end A for point D. 
CBAR/CBEAM Long. Stress SAE - The longitudnal (extensional) stress at end A for point E. 
CBAR/CBEAM Long. Stress SAF - The longitudnal (extensional) stress at end A for point F. 

CBAR/CBEAM Long. Stress SBC - The longitudnal (extensional) stress at end B for point C. 
CBAR/CBEAM Long. Stress SBD - The longitudnal (extensional) stress at end B for point D. 
CBAR/CBEAM Long. Stress SBE - The longitudnal (extensional) stress at end B for point E. 
CBAR/CBEAM Long. Stress SBF - The longitudnal (extensional) stress at end B for point F. 

CBAR/CBEAM Long. Stress SAMIN - Minimum value of longitudnal stress over points C, D, E and F at end A. 
CBAR/CBEAM Long. Stress SAMAX - Maximum value of longitudnal stress over points C, D, E and F at end A. 

CBAR/CBEAM Long. Stress SBMIN - Minimum value of longitudnal stress over points C, D, E and F at end B. 
CBAR/CBEAM Long. Stress SBMAX - Maximum value of longitudnal stress over points C, D, E and F at end B. 

Altair Forum User

Thank you very much Prakash!

Altair Forum User

Altair Forum User said:

Mr Prakash Pagadala,
I do not find attached powerpoint file, can you upload again？
thank you very much

 

Altair Forum User

Altair Forum User said:

To output the stress for the beam elements we need to need to specify the Stress Recovery Coefficients C1, C2, D1, D2, E1, E2, F1, F2 (4 points on the X-section) on the beam property card. 

C1, C2 (or D1, D2 ...) are the y and z coordinates in the BEAM element co-ordinate system of a point at which stresses are calculated. See the attached powerpoint for the visualization of this. For e.g if you need to calculate the stresses on the surface for the tubular x-section you could use the following values based on the outer diameter of the tube you are using: 

C1, C2 = 0.025, 0.000 
D1, D2 = 0.000, 0.025 
E1, E2 = -0.025, 0.000 
F1, F2 = 0.000, -0.025 

This is just an example, you can use any other coordinates. 

Now moving to HyperView post-processing the stresses you can contour are the following: 

CBAR/CBEAM Long. Stress SAC - The longitudnal (extensional) stress at end A for point C. positive values means tension, negative values means compression. 
CBAR/CBEAM Long. Stress SAD - The longitudnal (extensional) stress at end A for point D. 
CBAR/CBEAM Long. Stress SAE - The longitudnal (extensional) stress at end A for point E. 
CBAR/CBEAM Long. Stress SAF - The longitudnal (extensional) stress at end A for point F. 

CBAR/CBEAM Long. Stress SBC - The longitudnal (extensional) stress at end B for point C. 
CBAR/CBEAM Long. Stress SBD - The longitudnal (extensional) stress at end B for point D. 
CBAR/CBEAM Long. Stress SBE - The longitudnal (extensional) stress at end B for point E. 
CBAR/CBEAM Long. Stress SBF - The longitudnal (extensional) stress at end B for point F. 

CBAR/CBEAM Long. Stress SAMIN - Minimum value of longitudnal stress over points C, D, E and F at end A. 
CBAR/CBEAM Long. Stress SAMAX - Maximum value of longitudnal stress over points C, D, E and F at end A. 

CBAR/CBEAM Long. Stress SBMIN - Minimum value of longitudnal stress over points C, D, E and F at end B. 
CBAR/CBEAM Long. Stress SBMAX - Maximum value of longitudnal stress over points C, D, E and F at end B. 

What does mean the points A and B?

 

Thanks

Altair Forum User

Hi,

A and B are two end points of bar / beam elements and each end has four stress recovery points (C,D,E and F).

Vinicius

Hello everyone. I believe the answer to the problem is found in the following link 

https://community.altair.com/community?id=community_question&sys_id=5046c8761b2bd0908017dc61ec4bcb3a

 

 

best regards

Adriano A. Koga

By the way, if you use PBEAML or PBARL properties, the stress recovery points are automatically assigned, and it is much easier.

The only issue is for non-standard sections, then regular PBAR/PBEAM are needed.