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Composite Damage Modelling Femap / User-defined material

Composite Damage Modelling Femap / User-defined material

Composite Damage Modelling Femap / User-defined material

Dear all,

I hope you are keeping safe and well.

Does anyone know how can I implement a user-defined material law using Femap ?
The material law deals with the intralaminar damage modelling of UD composite at the mesoscale level.
I did a similar work involving UMAT/VUMAT subroutines to implement a damage model into Abaqus.

Please another question, does the CZM (Cohesive Zone Model)available in Femap ?
Thank you for any help you can provide.

RE: Composite Damage Modelling Femap / User-defined material

SOL 401 and 402 both support Cohesive elements to model adhesively bonded interfaces. These are solid elements that can reference the MATCZ card. Unfortunately I don't have much experience with these so I am taking some information from the Nastran Multi-Step Nonlinear Guide listed below. Is this what you are looking for?

Nastran Multi-Step Nonlinear Guide:
You use the MATCZ bulk entry when you want to obtain material damage estimates. To activate
damage estimation, include PARAM,MATNL,1 in your input file. On the MATCZ bulk entry, specify the
damage estimation model. You can choose from the following options:
• In the polynomial model (the default), the Mode I, Mode II, and Mode III damage variables are
taken to be equal, and the damage is modeled as a function of thermodynamic force. An
evolution equation is used to estimate the damage.
• In the bi-triangular model, for Mode I, Mode II, and Mode III, the relationship between stress and
displacement is modeled as bilinear.
• In the exponential model,for Mode I, Mode II, and Mode III, the relationship between stress
and displacement is modeled as exponential.

RE: Composite Damage Modelling Femap / User-defined material

Hi TG_eng,

Thank you for your feedback.

It sounds that the Cohesive element property cards exist. The idea is to represent the interface between 2 plies with a cohesive layer and check if the applied load induces delamination.

However, I would like also to include a bilinear material model dealing with the intralaminar damage including the damage onset based on failure criteria and the damage softening based on continuum damage mechanics theory. Do you know what's the appropriate tool to do it in Femap? is it API or DMAP(Direct Matrix Abstraction Program)?
On Abaqus UMAT or VUMAT subroutines are used to implement a material model (implicit or explicit).

Thank you for any information you can provide.

Graduate Stress Engineer

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