ANSYS stress analysis of pressure vessels
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This post was last edited by joyouscat on 2011-6-20 14:19. In the results obtained from ANSYS post-processing stress linearization: **MEMBRANE** represents membrane stress, **BENDING** represents bending stress, **MEMBRANE PLUS BENDING** represents membrane stress plus bending stress, and **PEAK** represents peak stress. What does **TOTAL** represent?
Is it combined stress? ANSYS is not very good at modeling applications
I couldn’t see clearly; I thought it was U2, ASME stress analysis design. I don’t understand this
TOTAL represents the total stress value
Reply to 4# Mixu Daxigua: I mainly want to know how this total stress value is taken into account in stress analysis evaluations. It seems that in other people’s analysis reports, such evaluations are not related to this total stress value at all. Why is that?
Because the report you are looking at is a strength analysis report; this total stress is only used in fatigue checks, and it is not necessary for strength analysis
Reply to 5# joyouscat: The stress cloud diagram is a result obtained using the finite element theory, based on elasticity mechanics (elastic-plastic mechanics); in other words, the total stress is the result derived from elasticity mechanics through the finite element method. The stress classification is based on plate-shell theory, rather than being purely derived from mechanical principles. Stress classification is informational in AMSE; this method has been widely used in pressure vessels for nearly 30 years, representing a good combination of theory and practical experience. The ANSYS software uses shell theory and various assumptions to linearize the total stress (membrane stress + bending stress + peak stress). For membrane stress, bending stress, and peak stress, refer to standards such as JB4732/ASME VIII-2; it is up to you to determine whether it is primary stress or secondary stress. There are four basic starting points for stress classification: 1. The cause of stress generation. 2. Methods for calculating stress. 3. Size of the area where stress exists. 4. Distribution characteristics of stress along the wall thickness. Different types of stress cause varying degrees of damage; it is therefore very important to understand the characteristics of stress. Total stress can be used in fatigue analysis; it is based on ASME Section VIII-2, but it is not the only method for assessing fatigue. Of course, those with a solid theoretical foundation will notice that there are certain issues with using linearized stress analysis to process FEA results; relevant literature is available for reference (if interested). In cases where the theory of complex structural plates and shells is not applicable, limit analysis is more scientific. Take a close look at the standard definition of JB4732. ANSYS is just a tool; the theoretical foundation is what truly matters.
May I ask how to display secondary stresses in ANSYS post-processing? It seems they are not available there. Please provide an explanation
Is there no stress linearization in the new version? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
Question: What do “SINT”, “SEQV”, and “TEMP” mean in the linearization results?
SINT: Stress intensity, third strength theory; equal to the first principal stress minus the third principal stress. SEQV: Equivalent stress, fourth strength theory; formula: sqrt(0.5)