The Mohr-Coulomb plasticity model in Abaqus need cohesion yield stress as function of plastic strain to model the hardening behavior of the material. Please help by explaining the procedure to generate the function. The abaqus manual explains only the theoretical part, as per the description, from the experimental data of triaxial test, I am not able to generate the required function. Is it possible to develop the function with the help of triaxial test data? Any alternate methods are there to find the same?
Hi Balaji,
Thanks for your response. The note contains the material properties of elastic and plastic behavior of steel. In my case its Mohr-Coulomb plasticity model which needs the input data as Cohesive yield stress and Equivalent plastic strain. I wish to know how this parameters are calculated for a material from a triaxial test data.
With Regards,
Nithin S
Hello Nithin,
Have you managed to solve this problem? I have the same problem and am unable to figure it out.
With regards,
Tim
This paper can help you: CHINESE JOURNAL OF GEOPHYSICS Vol.55, No.6, 2012, pp: 733∼741 MOHR-COULOMB YIELD CRITERION IN ROCK PLASTIC MECHANICS
Hello Nithin Sudersanan
The Mohr-Coulomb yield or failure criterion states that
τf = c + σ*tan ϕ
Generally, for a specified soil c and ϕ do not change with plastic strain provided the soil remains in the same state. Thus, for a normally consolidated soil c will be almost zero and ϕ will be about 30 deg.
However, c and ϕ will change if the soil becomes overconsolidated. Thus, c and ϕ will be functions of overconslidation ratio and not necessarily functions of plastic strain. You may derive this functional relations using a series of triaxial tests.
With respect to hardening. A material like soil hardens if its shear strength increases. Thus, for an M-C material the hardening parameter may be taken to be the normal stress σ because as it increases τf increases also.
A purely cohesive soil with ϕ = 0 cannot harden.
Dear nithin sunderson
Your issue is very complicated and detailed problem. I can't answer this question in one comment because it may go up to 3-4 pages. I recommend you to know more about the behavior of soil constitutive models. For the above purpose it is better to start with some books in order to read precise description. I attach the part of the book written by chen, named "Plasticity for structural engineers".
Good Luck
- Badges
- Science topic