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Does COMSOL support user-defined element like Abaqus does?

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Hi all,

Anyone knows if COMSOL support user-defined element like Abaqus does? I am now using eXtended finite element method(XFEM), in which, the elements cut by the interface are enriched, so there are generally additional terms and extra DOF in the displacement interpolation, for example, {u} = [N]{d} + [M]{a}, such that we need to define an additional shape function matrix [M] and the corresponding DOF vector {a}. Another problem comes up with numerical integrals in this enriched element, as [M] or its derivatives may discontinuous in the element, we need to further subdivide this enriched element and carry out Gauss quadrature in each of the subcells. Can COMSOL achieve this? or use Matlab m-file to write an interface subroutine to get this? Thank you very much for your answers.

Xujun

1 Reply Last Post 30 avr. 2015, 18:29 UTC−4
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Hello Xujun Zhao

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Posted: 10 years ago 30 avr. 2015, 18:29 UTC−4
Hi Xujun,

I have slmost same question about COMSOL? Did you come up with any results? Did it work for your case? Could you define your user-element for COMSOL?

This is my question asked in the discussion forum:
_______________________________________________________
I am new to COMSOL and have very basic question.
I am working of flow and stress in porous media. As part of my research, I will develop an element with specific degree of freedoms at nodes (corner and centric nodes), say fluid velocity, displacement, and fluid pressure (u-v-p formulation).

I was wondering if it is possible to write the element in the MATLAB (I'm mean K, C, and F matrix of of finite element) and use the COMSOL as preprocessor (for meshing and boundary conditions), and also solver. Something like what is done by UEL and UMAT for ABAQUS.
_______________________________________________________

Best Regards,
Sina
Hi Xujun, I have slmost same question about COMSOL? Did you come up with any results? Did it work for your case? Could you define your user-element for COMSOL? This is my question asked in the discussion forum: _______________________________________________________ I am new to COMSOL and have very basic question. I am working of flow and stress in porous media. As part of my research, I will develop an element with specific degree of freedoms at nodes (corner and centric nodes), say fluid velocity, displacement, and fluid pressure (u-v-p formulation). I was wondering if it is possible to write the element in the MATLAB (I'm mean K, C, and F matrix of of finite element) and use the COMSOL as preprocessor (for meshing and boundary conditions), and also solver. Something like what is done by UEL and UMAT for ABAQUS. _______________________________________________________ Best Regards, Sina

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