The shear response of metallic square honeycombs

Abstract

Stainless steel square honeycombs have been manufactured by slotting together steel sheets and then brazing the assembly. Their out-of-plane shear response is measured as a function of the relative density of the honeycomb and of the direction of shearing with respect to the material axes of the square honeycomb. The response is nearly isotropic with the shear strength and reasonably insensitive to the loading direction. In contrast to the out-of-plane compressive response, the shear response is monotonically hardening and the shear strength scales linearly with relative density. A simple analytical model based upon uniform deformation of the cell walls is in good agreement with the measured shear behavior at low shear strains, and predicts the onset of wrinkling of the cell walls to reasonable accuracy. Finite element (FE) calculations are accurate up to large values of shear strain, and reveal that the shear strength of the square honeycombs is relatively insensitive to the ratio of honeycomb height to cell size. The shear strength of square honeycombs compares favorably with other competing sandwich core topologies such as pyramidal and corrugated truss cores.

Optimization of support structures for selective laser melting.

“…The support structure explored in this paper is the commonly used block support structure which is shown in Figure 71 [127] in the XYZ coordinate system. The basic structure has three primary parameters: t (thickness), l (spacing) and h (height of the structure).…”

“…Tensile strength out of plane (Z direction) [127,132] Experiments and simple analyses have shown that their out of plane elastic properties scale linearly with the relative density ̅ [127] which is shown in Equation (45).…”

“…Shear stress in the plane (XY direction) [127] Elastic shear buckling strength of a clamped plate is given by Equation (49) [133]:…”

“…Note that for a honeycomb with aspect ratio 1, and clamped edges along Z = 0 and Z = h, k = 12.28 [127].…”

“…Square honeycomb structure [127] 77. Spreading of the twin cantilever depending on bar thickness (h) and measurement point (n) [134] …”