How to evaluate the curvature continuity?

[Kuruk]

Hello,
I feel the doubt in the equation of the curvature calculation of CATIA.

The curvature calculation of CATIA is evaluated by the following formula.
|C1-C2| / ( |C1+C2| / 2 )
(

http://www.eng-tips.com/viewthread.cfm?qid=99722&page=142)

Judging from this formula, it can obtain G2 continuous easily in the portion with a large curvature, and reversely, it never achieve G2 in the portion with a small curvature. (Even if there is a difference of the curvature of same level.)

Then, how should be done the admission decision on a continuous curvature in CATIA?

~~Sorry my bad english~~

 

[itsmyjob]

in order to have continuous curvature c1 should equals c2.

This will give you a result of 0 as c1-c2=0.

now the case when c1!=c2: let say r1=20 an r2=25 => c1=1/20 c2=1/25

|1/20-1/25| / (|1/20+1/25|/2) = .222 = 22%

when you have r1=1 and r2=6 (same difference of 5):

|1/1-1/6| / (|1/1+1/6|/2) = 1.42 =142%

now if you consider r2=r1*1.1 (110% of r1):

r1=1 r2=1.1 => |C1-C2| / ( |C1+C2| / 2 ) = 9.52%
r1=100 r2 = 110 => |C1-C2| / ( |C1+C2| / 2 ) = 9.52% !!!

so the curvature continuity is proportional the ratio of r1/r2.

Does this help?

Eric N.
indocti discant et ament meminisse periti ​