Is there an overview for the nomenclature of stress results in Hyperview?

Sebastian_981 · 2025-06-23T17:42:51+00:00

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Hello everyone,

In my random response analysis I get von mieses stress outputs with the prefix (Z1) or (Z2).

What exactly does that mean? Despite spending quite some time searching the docu I wasnt able to find an definitive answer. I only found this page on processing nastran results. There it is said that Z1 and Z2 refers to the upper and lower side of a shell. Id guess its the same for my OptiStruct results, but I want to be sure.

Ideal would be a docu page explaining the complete nomenclature for OptiStruct results in HyperView. I also found this community post basically asking the same question, but unfortunately the links to the pdf files in the replys dont work anymore.

Best regards,

Sebastian

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Accepted answers

Adriano_Koga

Z1 is bottom and Z2 is top.:

https://2021.help.altair.com/2021/hwsolvers/os/topics/solvers/os/pshell_bulk_r.htm#pshell_bulk_r__pshell_bulk_r_fn_y32_pzy_k1b

https://www.eng-tips.com/threads/definition-of-various-terms-of-a-shell-element.406953/

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HK2204

Hi Sebastian_981

the von Mises stress results are commonly post-processed and displayed with statistical prefixes like Z1, Z2, etc. These represent probabilistic stress estimates derived from the RMS (Root Mean Square) stress values,

Z0 RMS Stress

Z1 RMS + 1σ (≈ 84.1% probability not exceeded)

Z2 RMS + 2σ (≈ 97.7% probability not exceeded)

Sebastian_981

Thanks for the answer. but are you really sure about that? Could you point me to the corresponding documentation?

Im very sure that OptiStruct outputs the 1sigma values for everything. Also, obtaining the 2sigma and 3sigma value is archived by just multiplying the 1sigma value with 2 or 3, why would OptiStruct have an output for such an simple operation? Additionally, there is no Z0 stress output.

I apologize if Im wrong but this really sounds like you just fed my question to an LLM.

Adriano_Koga

Z1 is bottom and Z2 is top.:

https://2021.help.altair.com/2021/hwsolvers/os/topics/solvers/os/pshell_bulk_r.htm#pshell_bulk_r__pshell_bulk_r_fn_y32_pzy_k1b

https://www.eng-tips.com/threads/definition-of-various-terms-of-a-shell-element.406953/

Sebastian_981

Thank you!

I was only searching through the sections of the documentation concerning OptiStruct outputs in HyperView, no wonder I didnt find anything.