Altair Hyperworks 2022.1 Linear Buckling Analysis with Optistruct (OST-1040)

[@YiğitBağcı-g7i]

Why there are differences on LF at results depends 1D-2D-3D ? What is the reason?

[@ManuelRamsaier]

The most important difference regarding bucking analysis is about the eigenmodes you can simulate. Shell buckling eigenmodes can become far more complex than with 1D elements. Take a tube for example. A tube modelled with 1 d elements can deflect and buckle this war but you will not get something like a local buckling at a joint of tubes which is very important for some structures to analyze. So it depends on what you want to get from the model.

[@_helso]

Hi there, is the linear buckling analysis also possible, if the load is applied via enforced displacements (SPC or SPCD) instread of a force?

[@nguyenminhvo8820]

hi, I noticed that when exporting hyperworks results, it gives a lot of results such as displacement, von mises, shear stress,... What is the role of the results to be evaluated? ( How To Interpret Finite Element Analysis Results )

[@ManuelRamsaier]

It depends on the method of analysis. If you are considered with buckling analysis, the load factors are the most critical output request to pay attention to. If you are considered with doing a linear static analysis, diplacements might be of interest, for sure the von Mises Stress but as you can hear Lukasz and me discuss in the video about different analysis methods, it may give ridiculous high values. Then, nonlinear analysis, you might be more interested in the strain data as the stress will top out at yield. So it really depends what you want to analyze.

[@nguyenminhvo8820]

@@ManuelRamsaier - So what does the von mises value represent? - From the displacement output in the software, how to best identify the deformation from that displacement? Thank you very much

[@ManuelRamsaier]

@@nguyenminhvo8820 You want to know how much stress your material can withstand so you do testing on uniaxial loded specimen (just tension) and you will get yielding and ultimate stress values for that. The problem is that you do not have uniaxial stress condition in your part necessarily. To be able to compare your stress tensors in real life to a single number (e.g. the yield stress) form your tests, different hypotheses exist. One of which is the one with von Mises. The von Mises is derived from the stress tensor and gives you a single number to be compared with material strengths for ductile material and is used a lot. I would suggest that you check this in the literature as it is quite important, that you have a fair understanding of this matter.

[@nguyenminhvo8820]

@@ManuelRamsaier Thank you very much, can you share any documents that can help me understand these issues?

[@ManuelRamsaier]

​@@nguyenminhvo8820 Chech the youtube channel: TheEfficientEngineer Start with the oldest videos. If you can, watch them all. They will greatly enhance your understanding of mechanics. For books... there are a lot to recommend but any intodoction to mechancis book will cover this concepts.