Point Concentrations in Thick‐Faced Sandwich Beams

Abstract

The analysis of thick‐faced sandwich beams is reviewed with particular emphasis on responses within the regions of point loading. Examination of solution equations for three‐ and four‐point loading cases shows that point effects are highly localized, dissipating fully within a critical span away from the point load. The critical span length is constant, and stress concentrations and displacement distortions have constant magnitude when presented in terms relating to sandwich cross‐sectional geometry and material properties. Facing stress is magnified below the loading with an associated complementary reduction in core shear stress. Local face bending promotes reduction in overall displacement. Point effects are shown to be the major source of errors in the determination of sandwich properties by flexural testing methods. An alternative approach to such tests is suggested. A conjugate point method, which uses displacement positions outside the influence of the point effects, is shown to be much more accurate.