Calculate Damage parameter: Cohesive softening
Calculate Damage parameter: Cohesive softening
(OP)
Hi all,
For my research i want to model a bi-lineair softening curve of a cohesive element (see image below).
This should be able to be modelled in Abaqus CAE with a tabular damage evolution.
However the Abaqus user manual gives a formula to calculate the damage parameter for lineair softening, and another formula for exponential softening.
But not how to calculate the damage paramter for a given traction-separation diagram.
So how can i for a given set of points in the bi-linair softening curve, find the damage paramter (D)?
So that i can use these to model the damage evolution in Abaqus.

The points in this traction-separation diagram are the following:
Thanks in advance for any help.
For my research i want to model a bi-lineair softening curve of a cohesive element (see image below).
This should be able to be modelled in Abaqus CAE with a tabular damage evolution.
However the Abaqus user manual gives a formula to calculate the damage parameter for lineair softening, and another formula for exponential softening.
But not how to calculate the damage paramter for a given traction-separation diagram.
So how can i for a given set of points in the bi-linair softening curve, find the damage paramter (D)?
So that i can use these to model the damage evolution in Abaqus.

The points in this traction-separation diagram are the following:
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d e t 0.008082904 0 0 0.043118013 0.00112986 13.43787122 0.051200917 0.001996947 4.847601852 0.123627852 0.002230329 2.814681189 0.247255704 0.002463712 2.814681189
Thanks in advance for any help.





RE: Calculate Damage parameter: Cohesive softening
if you don't mind
can you share the pull out test simulation model? if possiblehttp://www.eng-tips.com/viewthread.cfm?qid=343838
many thanks
RE: Calculate Damage parameter: Cohesive softening
The pull-out data from the image above is the pull-out stress for a concrete-reinforcement interface.
I calculated the values for concrete C30/35 based on the analytical pull-out model of Den Uijl and Bigaj (1996).
Den Ujil, J. and Bigaj, A.J., (1996) A bondmodel for ribbed bars based on concrete loaded in compression. Heron nr. 41 (3), p.201–226
Hope this will help you!
However do you maybe have a suggestion how to find the damage parameters that are needed to model this softening behavior?
RE: Calculate Damage parameter: Cohesive softening
I am working on Rock samples, i have the stress-strain curve from the uni-axial compression test. the stress-strain curve for my rock sample is similar to yours.
I need to know how to calculate the damage variables, Actually i read the manual, but i did not find answer for my question. I wish you could help me.
Thank you in advance