Shear and Bending Stiffness of Single and Stacked Sandwich Beams

摘要

The objectives of this research were model the bending stiffness (EI), and the shear stiffness (GA) of some sandwich beams and to experimentally verify those predictions. The effort involved both single layer sandwich beams and stacked or multiple layer beams. The purpose of stacking two or more sandwich panels was to produce deeper, stiffer, and stronger specimens. In this case, faceplates are also located at intermediate locations, as well as top and bottom of the panels. The sandwich layers have been glued together using 3M Scotch-Weld 1838 B/A Green Epoxy. Three-point bending was used to experimentally determine the bending and shear stiffness of single and stacked sandwich beams of varying lengths. Since the basic Euler-Bernoulli beam theory ignores the effect of shear stresses and the resulting shear deformation for short beams, the Timoshenko beam theory was used. The general procedure for determining the values of EI and GA involved experimentally determining the slope of linear portion of the load-deflection curve for a given length. This yielded the value of w{sub}(max)/P for that length. The testing of various lengths produced a plot of 4w{sub}(max)/PL vs. L{sup}2. The slope of this line provided a good estimate of the value of 1/12E{sub}bI, while the extrapolated intercept yielded 1/A{sub}sG{sub}b.