Question about strain of triaxial compression simulation
Hi,
I got a question about the engineering strain and logarithmic strain in triaxial compression test.
For example, for one model I have (in which the axial loading is along y-axis.), I got:
Before deviatoric loading, the position of top wall and bottom wall is (0.035,0.14,0.035) and (0.035,0,0.035) respectively (i.e., height of 0.14), and the triax.strain=
The final position of top wall and bottom wall is (0.035,0.12,0.035) and (0.035,0,0.035) respectively. The -triax.
So the engineering strain is (0.14-0.
However, since triax.strain returns the logarithmic strain, it means that the logarithmic strain is 0.15 in axial direction (y direction). And from [1], the corresponding engineering strain is exp(0.15)-1=0.16
My question is why the engineering strain obtained from the two ways are different from each other. Do I misunderstand something?
Thanks
Leonard
[1]https:/
Question information
- Language:
- English Edit question
- Status:
- Solved
- For:
- Yade Edit question
- Assignee:
- No assignee Edit question
- Solved by:
- Leonard
- Solved:
- 2020-08-01
- Last query:
- 2020-08-01
- Last reply:
- 2020-08-01
Jan Stránský (honzik) said : | #1 |
Hello,
> Do I misunderstand something?
yes, the signs :-)
###
from math import log,exp
L = 0.14
l = 0.12
eEng = (l-L)/L
eLog = log(1+eEng)
eEng2 = exp(eLog) - 1
eEng2wrong = exp(-eLog) - 1
print("eEng",eEng) # -0.143
print("eLog",eLog) # -0.154
print("
print("
###
cheers
Jan
Leonard (z2521899293) said : | #2 |
Thanks Jan,
haha, what a stupid mistake :(
cheers
Leonard