OrlandoTaddeo87
Civil/Environmental
- Jan 28, 2015
- 24
Hi Guys!
I'm trying to model the contact between 2 surfaces using a cohesive layer with a traction-separation law.
I want to use a bi-linear constitutive behaviour, like the one reported in the image I attached; that bi-linear diagram is completely known to me. The behaviuor is the same in every direction (isotropic behaviour).
The program asks me to insert the following values to define the behaviour of the cohesive layer:
E/Enn
G1/Ess
G2/Ett
(or Knn, Kss and Ktt in the previous versions of Abaqus).
If I'm not wrong, E, G1 and G2 are the energies of fracture in the 3 directions of deformations, and I can determine them because they represent the area under the bi-linear curve (the area in grey in the image I attached).
Enn, Ess and Ett are the "elastic" stiffnesses of the cohesive element, and I can determine them because they represent the slope of the first branch of my bi-linear diagram.
The 1st question is: am I wrong? Can I use this method to insert that numerical values in Abaqus?
Moreover, to define the damaging behaviuor of the cohesive material, I'm asked to insert the subsequent quantities:
Nominal stress, Normal-Only mode
Nominal stress, First direction
Nominal stress, Second direction
I don't know what they are.
Thank you very much for your help!
Orlando
I'm trying to model the contact between 2 surfaces using a cohesive layer with a traction-separation law.
I want to use a bi-linear constitutive behaviour, like the one reported in the image I attached; that bi-linear diagram is completely known to me. The behaviuor is the same in every direction (isotropic behaviour).
The program asks me to insert the following values to define the behaviour of the cohesive layer:
E/Enn
G1/Ess
G2/Ett
(or Knn, Kss and Ktt in the previous versions of Abaqus).
If I'm not wrong, E, G1 and G2 are the energies of fracture in the 3 directions of deformations, and I can determine them because they represent the area under the bi-linear curve (the area in grey in the image I attached).
Enn, Ess and Ett are the "elastic" stiffnesses of the cohesive element, and I can determine them because they represent the slope of the first branch of my bi-linear diagram.
The 1st question is: am I wrong? Can I use this method to insert that numerical values in Abaqus?
Moreover, to define the damaging behaviuor of the cohesive material, I'm asked to insert the subsequent quantities:
Nominal stress, Normal-Only mode
Nominal stress, First direction
Nominal stress, Second direction
I don't know what they are.
Thank you very much for your help!
Orlando