Structurally graded core junctions in sandwich beams: quasi static loading conditions

The paper addresses the problem of sandwich beams/panels with junctions between different core materials. The physics of the impairing local effects induced by a mismatch of the elastic material properties at core junctions is discussed, and the results of an experimental investigation concerning the quasi-static failure behavior of sandwich beams with conventional butt and “structurally graded” core junctions is discussed. The term “structurally graded” core junctions include scarf junctions and junctions provided with local reinforcing patches of the faces. The influence of the junction interface geometry on the quasi-static deformation, failure initiation and crack patterns are studied experimentally for sandwich beams loaded in the three-point bending. It is shown that “structurally graded” core junctions perform better than conventional butt junctions, and thus improve the strength of the structure.