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MPC in Abaqus  


ichigo53
Posts: 3
(@ichigo53)
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Joined: 12 years ago

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.

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Jorgen
Posts: 3874
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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

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jmaikos
Posts: 36
(@jmaikos)
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Joined: 12 years ago

Please give me an advise

Hi there,

Im 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 dont understand clearly and have questions asking any guru as following,

- Whats 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?.

Thanks in advance.

KMM.

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Jorgen
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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

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jmaikos
Posts: 36
(@jmaikos)
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Joined: 12 years ago

Thanks a lot.

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kmmusi
Posts: 3
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Joined: 5 months ago

Dr.Jorgen,

As I understood, 1=JTYPE, 301 = dependent node, 300 = independent node. Why do the first nodes (301,302, ...) appear twice in JTYPE 1?

Thanks.

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