Contact Law for Composite Sandwich Beams

Abstract

In sandwich structures with soft foam core materials, the relationship between load and deflection under the load, also called contact law or indentation, plays a very important role. This work presents a combined experimental and analytical study of the contact behavior of sandwich beams with polyvinyl chloride (PVC) foam cores. The mechanical properties of the sandwich constituents were fully determined and sandwich beams, facesheet-foam and foam blocks were tested under quasi-static loading. These experimental results were used to model the load-deflection curve that includes a linear range followed by a nonlinear portion. The linear model was derived from the Winkler foundation theory and the nonlinear one was obtained by fitting experiments.

Nonlinear Stress and Deformation Behaviour of Composite Sandwich Beams

“…(6). From the values of these stresses and using the stress-strain curves of the facing material in tension and compression ( Figure 1) the corresponding compressive, ε c , and tensile, ε t, strains are determined.…”

“…An extensive amount of work has been performed at Northwestern University on the mechanical behaviour and failure of sandwich beams under four-and three-point bending and cantilever beams made of unidirectional carbon/epoxy (AS4/3501-6) facings and a PVC closed-cell foam (Divinycell) cores [1][2][3][4][5][6][7]. The load-deflection behaviour of these materials consists of an initial linear portion followed by a nonlinear part.…”

Investigation on the indentation behavior of sandwich beams using crushable and hyperelastic foam cores

“…In [6,7,9] a two parameters elastic foundation approach is used able to include also shear forces at the face-core interface while a justification for neglecting them in the case of sandwich beams, thus considering only normal forces (assumption found in the in the majority of works) is provided in [10]. Solutions are most frequently provided for the fully backed sandwich where the unloaded face is resting against a rigid foundation [2,3,5,9,[11][12][13][14]. Solutions for edge supported beams (e.g.…”

“…Solutions limited to an elastic compression behaviour of the foundation have been provided by many authors [2,3,[5][6][7][8][9]. Solutions are available for both sandwich beams [2,3,5,10,11] and plates [6][7][8][9]11]. In [6,7,9] a two parameters elastic foundation approach is used able to include also shear forces at the face-core interface while a justification for neglecting them in the case of sandwich beams, thus considering only normal forces (assumption found in the in the majority of works) is provided in [10].…”

“…Solutions limited to an elastic compression behaviour of the foundation have been provided by many authors [2,3,[5][6][7][8][9]. Solutions are available for both sandwich beams [2,3,5,10,11] and plates [6][7][8][9]11].…”