Formula to ignore internal cracks in Rules Based Mesher in CATIA V5-6.

 

 

Hi Everyone,

Rules Based Mesher (RBM) has the option to “ignore internal cracks” in the geometry tab of the editor box. The criteria to decide if a hole is a crack depends on two factors, Normalized Shape Factor (F) and Hole Surface Test compared to Mesh Size (S).


1.       F < 0.18, where F= 4*Pi*(Surface area of crack)/(Perimeter of crack^2) -> The hole is treated as a crack


2.       If F > 0.18, an additional test for S is performed

S < 0.005*(Mesh size^2) -> hole is treated as a crack.


 

For example, for a given crack size, RBM ignores the crack for a mesh size of 2mm, as shown in the table below.

Mesh Size

Crack length

Crack width

F

Result

S

Final result

2

0.3

0.1

2.356194

not crack

0.02

Not crack

3

0.3

0.1

2.356194

not crack

0.045

crack

 

Thanks,
Preeti