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[Ken Ng]

Hi,

I am trying to implement the hashin failure criteria into APDL command of the geometry, but I found I am confused with the DMGI input, I wonder what is the damage variable in the viscous dampinf coefficients stand for?

And whether the data in my hand is sufficient to get the energy dissipated and the viscous damping coefficient in DMGI:

Failure criteria:
Parallel tension = 108 MPa
Parallel compression = 29.8 MPa
Matrix tension = 2.3 MPa
Matrix compression = 5.5 MPa
Longitudinal shear = 7.8 MPa
Transverse shear = 7.8 MPa
Fracture energy 
Longitudinal tension = 1.6 N/mm
Longitudinal compression = 60 N/mm
Transverse tension = 0.06 N/mm
Transverse compression = 0.2 N/mm

[Saumadeep Choudhury]

 

Hi Ken Ng,

Implementing the Hashin failure criteria in ANSYS APDL requires understanding various inputs, including the damage variable in the viscous damping coefficients. The damage variable, typically denoted by ‘PDMG’ when using the ‘PLNSOL’ command, represents the state of damage in the material. It ranges from 0 (no damage) to 1 (total failure), but due to numerical considerations, it may not reach an exact value of 1, instead, it may approach 0.99999 to prevent the material stiffness from becoming zero and the matrix from becoming unsolvable. Refer to: /forum/forums/topic/hashin-failure-results/

The viscous damping coefficients, are specified for the different damage modes and are part of the damage evolution law, which regularizes the damage evolution. The coefficients are used in the constitutive equations that define the behavior of the material post-damage. It’s important to also specify a compatible material damage initiation criterion (TB, DMGI) to ensure that the damage evolution law affects the material as intended. Refer to: https://ansyshelp.ansys.com/Views/Secured/corp/v232/en/ans_mat/mat_damageall.html

 

Regards,

Saumadeep Choudhury

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