Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

How to convert Abaqus logarithmic strains to deformation gradient in global/local axis?

Status
Not open for further replies.

Waqas Rashid

Mechanical
Oct 13, 2022
2
Hi everyone,
If I have material orientation in global axis (i.e. X,Y,Z) and I apply biaxial stretch in Abaqus using single element, I get same deformation gradient analytically and Abaqus (transformed logarithmic strains into stretches etc.). Attached in case 1.
If material orientation of X-Y makes 30 degrees with global axis (i.e. X,Y ) and I apply biaxial stretch in Abaqus using single element, I get different deformation gradients analytically and Abaqus (although I am using all the necessary transformations). Attached in case 2.
The idea behind was to make sure that strains from Abaqus are either in global axis or local axis (in the direction of material orientation).
If someone knows where I am making mistake let me know. Thanks.
 
 https://files.engineering.com/getfile.aspx?folder=d9d3bd7c-7332-4fda-9f18-92314e17ce0d&file=analytical_vs_abaqus.docx
Replies continue below

Recommended for you

Which material model are you using in Abaqus ? Maybe you will find the source of this difference by requesting more output from Abaqus. It offers output variables even for quantities such as principal stretches and deformation gradient. And you could transform the results to a different coordinate system to make comparisons easier.
 
I am using Fung model in which I also wrote script. This method looked simple for me because I conpared both results when both orientations were same and results matched.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor