Hi, I have a simple model under a l

[mnm8020]

Hi, I have a simple model under a load. I want to find the load in which the von mises stress in one point in my model reaches a critical value. My model is a single pipe and the loading is internal gas pressure. I didn't find any tools in ABAQUS to define this criterion. How can I find this load? Should I employ a specific type of step or defining a damage? I have tried these methods but still I had no success.

 

[corus]

In the elastic region, stress is proportionate to load (assuming small deflection and no other non-linear effects). Use a unit load and then ratio the von Mises stress to yield to calculate the required load. Simples.

 

[mnm8020]

Thank you corus. No, My material and geomery are nonlinear. My material has hardening effects and I have introduced its stress-strain curve in plastic behavior in the program. what's your suggestion?

 

[burningDiesel]

Easiest:
Put a load larger than the one u expect, let abq write out a lot of timepoints, and just read it from the output (at time < 1).
If the material is not yet at yield, repeat with a higher load.

Pro:
use *EXTREME VALUE with HALT=YES

 

[burningDiesel]

Forgot to mention that option 2 is only for Abq/Explicit.
I don't know if there's something similar for standard.

 

[mnm8020]

Thanks sdebock. Can you explain the first option. you know I've already use it. But when I checked the reports I saw that the biggest mises stress is lower then the ultimate stress that I introduced by the stress-strain curve of my material. Another question: What does it mean? when I was checking mises stresses in rpt file it was mentioned that: "Loc 1 : Integration point values from source 1" and all numbers under the "Int Pt" were equal to 1?