Simulation of load-unload test in Abaqus

  • #1
Faezeh
1
0
Hello,

I am trying to simulate the load-unload test in Abaqus under the following loading schedule using my UMAT (which has already been validated).
Picture1.jpg

As you see, the load-unload test is pure tensile with positive displacements; however as I modelled it in Abaqus the force-displacement curve as well as the stress-strain curves give me some negative forces (stresses), while theoretically all the stresses and strains should be positive. Here is the numerical load-displacement curve which is obtained from Abaqus:
View attachment 343408
This is the experimental result (Stress-strain):

Picture5.jpg

As you see there shouldn't be any negative forces (stresses) in the model. I don't know what is the problem with the model. it should be noted that I tried the model which is in this YouTube video ()
 

Attachments

  • Picture4.jpg
    Picture4.jpg
    38.8 KB · Views: 5
Engineering news on Phys.org
  • #2
Hi,

I have encountered this issue in my cyclic loading tensile test simulation but only my stresses were negative. This usually occurs when you have defined a displacement boundary condition using amplitude to replicate the loading. Since we implement a defined displacement at a defined time step/increment, the stress tends to "overshoot" into the negative region to compensate for this definition as well as calculations done for the material by Abaqus.

I fixed it by increasing the resolution of the amplitude of loading i.e., more points in the amplitude (increasing increment from 0.001 to 0.0001 for example)

Also, I am unable to see your Abaqus result.

Hope this helps. Good luck.
 
  • #3
  • Like
Likes MMTUser1

Similar threads

  • Mechanical Engineering
Replies
14
Views
567
  • Mechanical Engineering
Replies
1
Views
1K
Replies
1
Views
2K
  • Mechanical Engineering
Replies
3
Views
341
  • Mechanical Engineering
Replies
5
Views
1K
Replies
5
Views
796
Replies
4
Views
195
  • Mechanical Engineering
Replies
1
Views
946
  • Mechanical Engineering
Replies
2
Views
836
  • Mechanical Engineering
Replies
6
Views
2K
Back
Top