Buckling Composite Curved Panel 3

[rybose]

Looking for some methods to perform a buckling analysis on a composite cylindrical panel (simply supported on all edges).

Most references for cylindrical shell buckling seem to implicitly assume a full cylinder.

Whitney (Structural Analysis of Anisotropic Plates) has a solution for a curved panel on pg. 253. However the equation is giving me bogus results.

The expressions he derives in Eq 9.55 look suspect. There is no plate width (b) dependence in any of the expressions, and the lambda_2mn term has two R variables in the second term. It's unclear from the discussion on pg. 253 where the R term is the radius or the aspect ratio (a/b).

Has anyone had any experience with this formulation?

 

[ESPcomposites]

I have not used Whitney's solution for this, but have found some of the other equations to be in error as well. Please report back if you can find some meaningful results. I have an Excel/FEM based solution for composite buckling and am looking to extend its capabilities. I will need some way to be compare the results.

Brian

http://www.espcomposites.com

 

[irq]

Here you can find my thread about failure of sandwich composites:

http://www.eng-tips.com/viewthread.cfm?qid=281946&page=1

I decided to continue this topic and I have performed the FE-Analysis (nonlinear) of the curved glas fibre thin-walled (R/t ~300) sandwich panel (similar to the 2d-problem described in the linked thread, but with more complicated geometry, cutouts etc.) to predict the critical buckling load. In general the geometric nonlinear solution should be sensitive to imperfections, and knock-down factor must not be applied. Is it true for composites? The prediction of eigenvalue is about 1.4 and it seems to me to low to be sure, that the analysed part will pass the test.

What knock-down factor do you usually use in your analysis of composites?

 

[composiman]

Try

http://www.abdmatrix.com

for resources on buckling of composites.

 

[RPstress]

ESDU program A9704 (Previously A8725 or 1068), data item 97004 "ELASTIC BUCKLING OF CYLINDRICALLY CURVED FIBRE REINFORCED COMPOSITE PANELS WITH ALL EDGES SIMPLY-SUPPORTED UNDER BIAXIAL LOADING."

ESDU 94007, "ELASTIC BUCKLING OF CYLINDRICALLY CURVED LAMINATED FIBRE REINFORCED COMPOSITE PANELS WITH ALL EDGES SIMPLY-SUPPORTED UNDER BIAXIAL LOADING." Plus another program, A9407.

AIAA-87-0728-CP "Buckling Laminated Shells Including Transverse Shear Flexibility", Ward and McClesky.

NACA TN 3783, "HANDBOOK OF STRUCTURAL STABILITY PART III - BUCKLING OF CURVED PLATES AND SHELLS."

NASA TN D-163, "HANDBOOK OF STRUCTURAL STABILITY SUPPLEMENT TO PART III - BUCKLING OF CURVED PLATES AND SHELLS."

NASA CR-1457, "MANUAL FOR STRUCTURAL STABILITY ANALYSIS OF SANDWICH PLATES AND SHELLS."

NASA CR 912, "Shell Analysis Manual."

 

[rb1957]

thx for adding to my library !

 

[RPstress]

I just wish I'd been sensible enough to note down where I found my refs (mostly online), but I was too stupid.

(I'm wee a bit better these days, but it's still awkward creating a text file with the URL in it with the same as a .pdf, or editing in some text with 'PDF-XChange Viewer'. We could really do some sort of 'attach this label or text to this file' facility. Any one know of such a thing?)

 

[rb1957]

the NASA site finds the NACA and NASA docs easily enough. funnily enough NACA's handbook of Structural Stability doesn't seem to have a part VI (it has a 5 and a 7 but no 6) ?? 5 is TN3785, 7 is D162

 

[jimkinney]

Part VI is NACA TN-3786 and is here:

http://ntrs.nasa.gov/search.jsp?R=2...=all&Ntx=mode+matchall&Ns=HarvestDate%7c1&N=0

Jim

Jim Kinney
Kennedy Space Center, FL