cosmoswork buckling analysis result does not match hand calculation
cosmoswork buckling analysis result does not match hand calculation
(OP)
I am trying to do a simple buckling analysis of a delrin pressure case using cosmoswork.
Case dimension:
OD: 8"
wall thickness: .4"
End cap thickness: .4"
Length: 2.625"
Material properties:
E: 2.83E+9 Pa
Yield stress: 8.9e+6 Pa
Poisson ratio: .3
Test load: 14.7 Psi
According to Roarks's Formulas the end cap should fail approx around 10m.
But the program give a load factor of 54 and the center of the end cap bulge outward rather than inward.
I am wondering wether I setup the analysis correctly? Any help or advice would be greatly appreciated.
Thanks
Case dimension:
OD: 8"
wall thickness: .4"
End cap thickness: .4"
Length: 2.625"
Material properties:
E: 2.83E+9 Pa
Yield stress: 8.9e+6 Pa
Poisson ratio: .3
Test load: 14.7 Psi
According to Roarks's Formulas the end cap should fail approx around 10m.
But the program give a load factor of 54 and the center of the end cap bulge outward rather than inward.
I am wondering wether I setup the analysis correctly? Any help or advice would be greatly appreciated.
Thanks






RE: cosmoswork buckling analysis result does not match hand calculation
I did a very quick run and go the same answer 54. Sounds good, right?
No. The problem is that you appear to be using the CW "linearized buckling analysis" that uses a linear analysis engine that does not account for the membrane stress created due to deflection. I believe this membrane stress is significant in this analysis so you should not be using this method.
Regards,
ERT
http://www.akeng.com
RE: cosmoswork buckling analysis result does not match hand calculation
corus
RE: cosmoswork buckling analysis result does not match hand calculation
Thank again.
Donald
RE: cosmoswork buckling analysis result does not match hand calculation
We must have different versions of Roark as our case numbers do not line up.
I think that you should focus on the end cap. Can you find a case that has edge compression and lateral pressure? I cannot.
Sounds like a physical test maybe a better approach.
Regards,
ERT
RE: cosmoswork buckling analysis result does not match hand calculation
corus