Summary
A series of tests were conduted on simply supported sandwich panels with two edges loaded in compression and with a thermal gradient between the two facings. The results of these tests, on aluminum and stainless-steel honeycomb-sandwich panels, are compared with a new theory with good correlation in the elastic range. Empirically, it was found that the experimental deflection pattern correlates well with the assumed orthogonal sine-wave deflection pattern.
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Abbreviations
- b :
-
one half of the panel length
- c :
-
edge-fixidity coefficient
- D :
-
\(E't\bar t^2 /[4b^2 (1 + m)(1 - \mu ^2 )]\)= the flexural rigidity
- E″ :
-
Young's modulus of the hot face
- E′ :
-
Young's modulus of the cold face
- E :
-
Young's modulus of the core
- \(\bar G\) :
-
shear modulus of the core
- m=E″/E′ :
-
ratio of Young's modulus of the hot facing to that of the col
- P :
-
edge-compression load
- P E :
-
\(4\pi ^2 E''t\bar t^2 /[b^2 (1 + m)(1 - \mu ^2 )]\)= critical cylindrical load of the panel (width of panel → ∞)
- P critical :
-
critical edge-compression load for the panel
- \(r = P_E /4\bar E\bar G\) :
-
core shear-stiffness parameter
- t :
-
thickness of the facings
- \(\bar t\) :
-
thickness of the core
- T″ :
-
temperature of the hot face
- T′ :
-
temperature of the cold face
- x=x′/b :
-
nondimensional horizontal distance from the panel
- x′ :
-
horizontal distance from the panel edge
- y=y′/b :
-
nondimensional vertical distance from the panel edge
- y′ :
-
vertical distance from the panel edge
- W xy 0 :
-
initial thermal deflection atx,y on the panel
- W xy :
-
additional deflection from the initially warped configuration atx,y on the panel
- W xy T :
-
total deflection atx,y on the panel
- μ:
-
Poisson's ratio of the face
References
Boller, K.H., Buckling Loads of Flat, Sandwich Panels in Compression.Report No. 1525-A, United States Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, Wis. (1954).
Chang, C. C., andEbcioglu, I. K., Elastic Instability of Rectangular Sandwich Panel of Orthotropci Core with Different Face Thicknesses and Materials.Jour. Appl. Mech.,27,474–480 (Sept. 1960).
Chang, C. C., andFang, B. T., Initially Warped Sandwich Panel under Combined Loadings, Jour. Aerospace Sci., 27, No. 10, 779–787 (Oct. 1960).
Chang, C. C., andEbcioglu, I. K., Thermo-Elastic Behavior of a Simply-Supported Sandwich Panel Under Large Temperature Gradient and Edge Compression Ibid., 28, No. 6, 480–492 (June 1961).
Additional information
C. C. Chang was Professor of Fluid Mechanics, Aeronautical Engineering Department, University of Minnesota; is presently associated with Aerospace Corp., El Segundo, Calif. M. J. Timmons was formerly Research Fellow, is now Project Engineer with FluiDyne Engineering Corp., Minneapolis, Minn.
This project was sponsored as part of Air Force Contract AF 18(603)-112 by the Mechanics Division, Air Force Office of Scientific Research, ARDC.
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Chang, C.C., Timmons, M.J. Compression tests of sandwich panels with facings at different temperatures. Experimental Mechanics 2, 249–256 (1962). https://doi.org/10.1007/BF02326724
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DOI: https://doi.org/10.1007/BF02326724