High‐Order Behavior of Sandwich Beams with Flexible Core and Transverse Diaphragms
Publication: Journal of Engineering Mechanics
Volume 119, Issue 5
Abstract
The bending behavior of a sandwich beam with transversely “soft” core and transverse diaphragms is analytically investigated using variational principles. The beam consists of one or two skins, upper and lower, interconnected at discrete locations through transverse diaphragms, metallic or composite laminated, with a symmetric lay‐up and a fully or partially bonded (delaminated) transverse flexible core made of foam or low‐strength honeycomb type. The diaphragm is rigidly connected to the skins but may be bonded or unbonded with the adjacent core through its entire height. The analysis considers the discrete diaphragm as a concentrated interference that affects the beam's behavior through particular boundary and continuity conditions. The behavior of the beam is determined with the aid of a high‐order theory that uses a two‐dimensional elasticity formulation for the core, in the longitudinal and the transverse directions, combined with a beam theory for the skins and the diaphragms. The core‐diaphragm interaction is determined explicitly for the bonded and the unbonded cases and the equivalent conditions in terms of the solution unknowns are derived. The presence of a discrete diaphragm yields concentrated effects that affect the beam's behavior globally and locally. These localized effects are significantly important for the safety of the structure and are explicitly determined by the analysis for the entire structure as well as in the vicinity of the diaphragm. A study that investigates the effects of the existence of a reinforcing diaphragm and its interaction with the adjacent core in a vertical cut‐off end connection between a sandwich panel and its supporting members is presented, including the level of stress concentration involved.
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References
1.
Allen, H. G. (1969). Analysis and design of structural sandwich panels. Pergamon Press, London, U.K.
2.
Chandrashekhara, K., and Krishnamurthy (1990). “Free vibration of composite beams including rotary inertia and shear deformation.” Composite Struct., 14, 269–279.
3.
Chorloton, F. (1965). Ordinary differential and difference equations, theory and applications. Van Nostrand Company, London, U.K.
4.
Frostig, Y., and Baruch, M. (1990). “Bending of sandwich beams with transversely flexible core.” AIAA J., 28(3), 523–531.
5.
Frostig, Y., Baruch, M., Vilnay, O., and Sheinman, I. (1991). “Sandwich beams with unsymmetrical skins and a flexible core—bending behavior.” J. Engrg. Mech., ASCE, 117(9), 1931–1952.
6.
Frostig, Y. (1992a). “Behavior of delaminated sandwich beams with transversely flexible core—high order theory.” Composite Struct., 20(1), 1–16.
7.
Frostig, Y., Baruch, M., Vilnay, O., and Sheinman, I. (1992b). “A high order theory for the bending of sandwich beams with a flexible core.” J. Engrg. Mech., ASCE, 118(5), 1026–1043.
8.
Hockman, L. E. (1973). “Sandwich construction and design.” Analysis and design of flight vehicle structure, S. R. Jacobs and Associates, Indiana.
9.
Holt, D. J., and Webber, J. P. H. (1982). “Exact solution to some honeycomb sandwich beam, plate and shell problems.” J. Strain Analysis, 17(1).
10.
Kant, T., and Mallikarjuna (1989). “A high‐order theory for free vibration of unsymmetrically laminated composite and sandwich plates—finite element evaluation.” Computers and Struct., 32(5), 1125–1132.
11.
Kant, T., and Patil, H. S. (1991). “Buckling load of sandwich columns with a higher‐order theory.” J. Reinforced Plastics and Composites, 10(1), 102–109.
12.
Marshal, A. (1982). “Sandwich construction.” Handbook of composites, Van Nostrand Reinhold Co.
13.
Monforton, G. R., and Ibrahim, I. M. (1977). “Modified stiffness formulation of unbalanced anisotropic sandwich plates.” Int. J. Mech. Sci., 19, 335–343.
14.
“Mechanical properties of Hexcel honeycomb materials.” (1982). TSB120, Hexcel Corp., Dubin, California.
15.
Ogorkiewicz, R. M., and Sayigh, A. A. M. (1973). “Deflection of carbon fiber/acrylic foam sandwich beams.” Composites, (Nov.), 254–257.
16.
Ojalvo, I. V. (1977). “Departures from classical beam theory in laminated sandwich and short beams.” AIAA J., 15(10), 1518–1521.
17.
Pearce, T. R. A., “The stability of simply‐supported sandwich panels with fiber reinforced face plates.” Ph.D. Thesis, University of Bristol.
18.
Plantema, F. J. (1966). Sandwich construction. John Wiley and Sons. New York, N.Y.
19.
Reissner, E. (1947). “On bending of elastic plates.” Quarterly J. Applied Math., 5(4), 55–68.
20.
Reissner, E. (1948). “Finite deflections of sandwich plates.” J. Aerospace Sci., 15(7), 435–440.
21.
Schwartz, R. T., and Rosato, D. V. (1969). “Structural‐sandwich construction.” Composite engineering laminates, MIT Press, Cambridge, Mass., 165–194.
22.
Senthilnathan, N. R., Lim, S. P., Lee, K. H., and Chow, S. T. (1988). “Vibration of laminated orthotropic plates using a simplified higher‐order deformation theory.” Composite Struct., 10, 211–229.
23.
Whitney, J. M. (1987). Structural analysis of laminated anisotropic plates. Technomic Publishing Co., Lancaster, Penn.
Information & Authors
Information
Published In
Journal of Engineering Mechanics
Volume 119 • Issue 5 • May 1993
Pages: 955 - 972
Copyright
Copyright © 1993 American Society of Civil Engineers.
History
Received: Jun 5, 1992
Published online: May 1, 1993
Published in print: May 1993
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