Why von-Mises will exceed stress constraint

Altair Forum User

I am doing the example of stress constraint of Hook

 

like this link : https://connect.altair.com/CP/SA/training/self_paced/optimization/content/opt3/pdf/ex1b.pdf

 

I want to konw why I set the stress is 120MPa

 

at the result stress will exceed at the design region but when I pick all region (contain non-design region) it will not exceed like this photo

 

<?xml version="1.0" encoding="UTF-8"?>

 

and I want to know the stress constraint is constraint the von-Mises stress? 

 

 

Altair Forum User

Hi,

 

The stress target in topology optimization is applied globally to the model (including non-design space). Please refer to the online help for the DTPL card (especially comment #1). It is through the DTPL card and not a DCONSTR
From FAQ section of help:
The stress constraint definition in a topology optimization is a global constraint and does not target local stress concentrations. These areas can be addressed subsequently through size, shape, and free shape optimization or a combination thereof. Artificial stress concentrations are filtered out during topology optimization with stress constraints.