1. Junior Member
Join Date
2008-08
Posts
3

## MPC in Abaqus

Hi,

Does anybody have any experience with modeling crack propagation using MPC in abaqus??
I am using MPC to release nodes along my crackpath (which happens to be along the line of symmetry). I wanted to know as to how the MPC is defined in terms of dependent and independent nodes. I have written a USDFLD for damage criteria, which if becomes =1 then the node is meant to be released. I have also written a MPC subroutine but I am not seeing any node release in spite of Damage=1.

I would be glad if anyone could tell me how the nodes are defined / connected in the subroutine or share their valuable experiences.

2. I have not used MPC for failure. I typically use the "fail" flag in a VUMAT instead.
Another option might be to use cohesive elements.

- Jorgen

3. KMM
Member
Join Date
2008-10
Posts
36

Hi there,

I'm an Abaqus beginner focusing on MPC user-subroutine for my research. I started learning from its manul, example "4.10.8 3DNLG-8: Collapse of a straight pipe segment under pure bending" from Abaqus Benchmarks Manual. From mpc part of that example,
*MPC,USER, MODE=NODE
1,301,301,300
1,302,302,300
1,303,303,300
1,304,304,300
1,305,305,300
1,306,306,300
1,307,307,300
1,308,308,300
1,309,309,300
1,310,310,300
1,311,311,300
1,312,312,300
1,313,313,300
2,301,302,303,304,305,306,307,308,309,310,311,312, 313,300

I don't understand clearly and have questions asking any guru as following;

- What's meaning of 1 and 2 in front of each line?. As I understand, 1 stands for depentdent nodes group and 2 for independent nodes group.

-Why it has to repeat node twice in 1?.

KMM.

4. The first number on each line is an integer key to be used in user subroutine MPC to distinguish between different constraint types. This all depends on the actual MPC subroutine.

-Jorgen

5. KMM
Member
Join Date
2008-10
Posts
36
Thanks a lot.