Iso value in Hyperview
After performing topology optimization when using Hyperview to see the results, In static analysis result page we have stress and displacement. I want to know that the demonstrated stress and displacement for las iteration are for wich iso value?
I don't understand how should I determine the value of iso value? For example 0.3 is better or 0.5 ? and the displacement and stress demonstrated are for structure with iso value of for instance 0.3 or 0.5?
Why the static analysis results (stress and displacement) is different from results of iteration 0 in optmization?
Thanks in advance for your reply
Answers
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Hi,
Iso value helps in interpreting designs and understanding load paths. During the course of Optimization the density value continuously changes from 0 to 1 (normalized value). At the end of the last iteration each element would have retained some material density and this is based on the strain energy.
Higher the strain energy density inside an element higher is the density value (say closer to 1). You can safely assume that elements with lower density values do not take much part in carrying the loads so elements with density values up to 0.3 or 0.4 can be discarded and the remaining elements with higher values carried forward for design fine tuning. To interpret designs better from a topology run you can use the DISCRETE parameter which pushes all semi dense elements closer to either 0 or 1.
This results in a discrete design and avoids the guessing of what density value should be chosen for the Iso Value plot.
A final optimization can then fine tune the design at the boundaries and hence allow local stiffening for reducing stresses.
I hope this explains.
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The iso value when you are post processing topology optimization results, represents the element density values between 0 and 1. sp when you use the value 0.3 you are specifying display of elements that have density more than 0.3 to 1.0
Use this tool to get a better look at the material layout and the load paths from OptiStruct.
This is more of a visualisation tool, the density threshold matters when you are extracting the geometry, say in OSSmooth,
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