Large deformation: ABAQUS Standard or Explicit?
Large deformation: ABAQUS Standard or Explicit?
(OP)
I am trying to simulate the effect of gravity on an object (breast). The breast under-goes large deformations because of gravity, the pendulum length of breast almost doubles between the positions am interested in.
Initially I used static, general analysis and I got error "Error in job Job-1: Time increment required is less than the minimum specified".
Then I used to explicit analysis and I got result i.e. deformed breast which looks sensible. But it leaves me with a question whether my analysis is valid or not. Attached is plot for IE and KE, the KE/IE is not in the recommended range of 1-5% for most part of the analysis. In this curve I dont understand is why is the energy profile oscillating.
To understand the difference between standard and explicit, I drew and meshed a hemisphere and assigned it properties of breast tissue and applied gravity to it using standard and explicit analysis separately. Between the two analysis, I found that the deformation are quite similar though there is difference in the magnitude of deformation by about 5-20%. In explicit analysis again KE & IE had oscillating profile and the KE was not in the 1-5% of IE.
Any comments and guidance would be very helpful.
Thanks
Prab
Initially I used static, general analysis and I got error "Error in job Job-1: Time increment required is less than the minimum specified".
Then I used to explicit analysis and I got result i.e. deformed breast which looks sensible. But it leaves me with a question whether my analysis is valid or not. Attached is plot for IE and KE, the KE/IE is not in the recommended range of 1-5% for most part of the analysis. In this curve I dont understand is why is the energy profile oscillating.
To understand the difference between standard and explicit, I drew and meshed a hemisphere and assigned it properties of breast tissue and applied gravity to it using standard and explicit analysis separately. Between the two analysis, I found that the deformation are quite similar though there is difference in the magnitude of deformation by about 5-20%. In explicit analysis again KE & IE had oscillating profile and the KE was not in the 1-5% of IE.
Any comments and guidance would be very helpful.
Thanks
Prab





RE: Large deformation: ABAQUS Standard or Explicit?
RE: Large deformation: ABAQUS Standard or Explicit?
That is a symptom; not the cause. You must find out the reason behind non-convergence.
Not a good reason to use explicit analysis. I believe static or visco should be sufficient for this problem (unless impacts of some sort are involved.) In explicit, equilibrium is not enforced, which may explain the difference in displacements.
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Large deformation: ABAQUS Standard or Explicit?
RE: Large deformation: ABAQUS Standard or Explicit?
Attach is inp file for the standard analysis.
RE: Large deformation: ABAQUS Standard or Explicit?
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Large deformation: ABAQUS Standard or Explicit?
RE: Large deformation: ABAQUS Standard or Explicit?
And also, you might want to consider viscoelastic properties and the visco step for this problem, unless final equilibrium states are of interest to you.
http://www.eng-tips.com/faqs.cfm?fid=376
http://www.eng-tips.com/faqs.cfm?fid=1083
RE: Large deformation: ABAQUS Standard or Explicit?
I am interested in the final equlibrium state only.
Thank you again!