Cervenka Consulting Forums — Unexpected Stresses in Shell Elements

Re: Unexpected Stresses in Shell Elements

null@example.com (dpryl) — Tue, 02 Apr 2013 07:43:30 +0000

Hello, you can send us your model (without results, ZIPped) along with your ATENA User ID (WR).

Re: Unexpected Stresses in Shell Elements

null@example.com (ah) — Sat, 30 Mar 2013 03:05:37 +0000

Thank you very much for your reply.
I checked the mentioned section of Atena Troubleshooting. Unfortunately, the problem that I have was not because of extrapolation. Also, the plate is a steel plate and no reinforcement is used.
Is it possible that I send you the input file so you could have a look? I will really appreciate this.
Many thanks

Re: Unexpected Stresses in Shell Elements

null@example.com (dpryl) — Fri, 29 Mar 2013 10:33:41 +0000

Hello, please read ATENA Troubleshooting, section "2.1.21 The tensile (or compressive) stresses exceed the tensile (or compressive) strength or yield stress – what is wrong?".

Without seeing your model and a description+sketch of the experimental setup, I can only try to guess the source of the difference:
If reinforcement failure limits the capacity during the experiment, and you use an ideal-plastic working diagram for the steel, i.e., without any limit strain, the capacity can be significantly overestimated.

Unexpected Stresses in Shell Elements

null@example.com (ah) — Fri, 29 Mar 2013 06:35:53 +0000

Hi,
I am modelling a steel plate which is subjected to out of plane loading. Shell elements with 6 layers are used. The strain hardening of the steel material is defined close to zero. Hence, stresses higher than yield stress are not expected.
When comparing with experimental results, the stiffness agrees well; however, for the maximum load capacity of the plate, the FE results are as high as twice of the experimental data.
Also, normal stresses and the max principal stresses are considerably higher than what they can be in accordance to the material definition.
Could you please let me know if you have any suggestions to fix the problem?
Thank you.