Learning Forum

[Paul_Loeps]

Hello reader,

as written in the header, I want to use a custom formulation to determine the equivalent SIF and the crack-growth direction for a 2D mixed mode. Is it possible to change the formulations which are used by ANSYS?

Thanks in advance.

[Daniel Shaw]

No. MAPDL uses the integration integral method to calculate the SIFs. You cannot specify a different method. See Section 2.4.2.4 in the MAPDL Fracture Analysis Guide.
You can create a user defined crack-growth law. See Section 3.1.3.4 in the MAPDL Fracture Analysis Guide.

[Paul_Loeps]

Thanks for the fast answer Daniel.
I don't want to change the method each SIF is calculated but the method how ANSYS calculates the averaged SIF. As much as I know, in the current version ANSYS calculates the equivalent SIF with the following equation:
An determines the angle of the crack growth by:
I want to change these two to the criterion formulated by Richard:
I don't know whether it is possible to change it in an easy way or find the formulation in the related file.