Abstract
A fixture for testing curved sandwich beams in flexure was designed and evaluated. The test specimen is a continuous sandwich beam consisting of a central circular 90° region connected by two straight legs. The fixture was designed according to the four-point flexure principle to produce a pure bending moment in the curved region. The validity of the test fixture in producing the desired loading was examined by fitting a curved aluminum bar of similar bending stiffness as the sandwich beams considered. Strain gage readings were successfully compared to predictions from curved homogeneous beam theory. In addition, the deflection of the beam at the loading points was analyzed using straight and curved beam theory for the various sections of the beam, and predictions were compared to measured load-displacement response. Good agreement was achieved between experimental and analytical results lending confidence to the test principle. Curved sandwich beams consisting of glass/polyester face sheets over a PVC foam core were tested to failure and the loading response of the beams and their failure behavior are discussed. It was found that the beams failed at the upper face/core interface due to radial tension stress.
Similar content being viewed by others
References
Allen, H.G., Analysis and Design of Structural Sandwich Panels, Pergamon Press, Oxford (1969).
Plantema, F.J., Sandwich Construction: The Bending and Buckling of Sandwich Beams, Plates and Shells, John Wiley, New York (1966).
Zenkert, D., An Introduction to Sandwich Construction, Chameleon Press, London (1997).
Vinson, J.R., The Behavior of Sandwich Structures of Isotropic and Composite Materials, Technomic, Lancaster (1999).
Smidt, S., “Curved Sandwich Beams and Panels: Theoretical and Experimental Studies,”Report 9310, Department of Lightweight Structures, Royal Institute of Technology, Stockholm (1993).
ASTM standard D 6415-99, “Standard Test Method For Measuring the Curved Beam Strength of a Fiber-reinforced Polymer Matrix Composite,” American Society for Testing and Materials, West Consohocken (2001).
Cook, R.D. andYoung, W.C., Advanced Mechanics of Materials, 2nd ed., Prentice Hall, Upper Saddle River (1999).
Whitney, J.M., Structural Analysis of Laminated Anisotropic Plates, Technomic, Lancaster (1987).
Askeland, D. L., The Science and Engineering of Materials (3rd ed.),PWS Publishing, Boston (1994).
Smidt, S., “Bending of Curved Sandwich Beams,”Report 9411, Department of Lightweight Structures, Royal Institute of Technology, Stockholm (1995).
Layne, A. M., “Flexural Failure of Curved Sandwich Beams with Implanted Interfacial Debonds,”Master Thesis, Florida Atlantic University, Boca Raton, (Aug. 2000).
Carlsson, L. A. andPipes, R. B., Experimental Characterization of Advanced Composite Materials, 2nd ed., Technomic, Lancaster (1997).
Smidt, S., “Bending of Curved Sandwich Beams, a Numerical Approach,”Compos. Structures, Vol. 34, 279–290 (1996).
ASTM Standard C297-94, “Standard Method for Flatwise Tensile Strength of Sandwich Constructions,” American Society for Testing and Materials, West Consohocken (2001).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Layne, A.M., Carlsson, L.A. Test method for measuring strength of a curved sandwich beam. Experimental Mechanics 42, 194–199 (2002). https://doi.org/10.1007/BF02410883
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02410883