抄録
The bending stress distribution in a sandwich composite beam is different from that derived by the conventional composite beam theory because of the shear effect of core, especially when the ratio of elastic moduli of face to core (k=Ef/Ec) is large.
In this study, the stress distributions in house-building sandwich materials under four-point bending are analysed by introducing the multi-layer built-up theory. The bending stiffness of face and core and the slip between both faces are taken into consideration in the present analysis.
The photoelastic measurements on model specimens having four kinds of k values are carried out and the applicable ranges of both theories are discussed comparing with the experimental results. The stress distributions in sandwich composite beams having k larger than 120 can be well explained by the multi-layer built-up theory.
The ratio of the coupling moment due to axial forces in both faces to the applied total moment in the uniform-bending range, which denotes the sandwich structural efficiency, can be well estimated by the multi-layer built-up theory. This simple one-dimensional theory will be useful in the structural design of sandwich construction.
