Fabrication and characterization of microscale sandwich beams

Microscale sandwich beams with cell diameters and wall widths down to 150 a nd 15 mum. respectively, and having both metallic and polymer/metal cores w ere produced through fabrication methods that combined photolithography and electrodeposition. Various core structures were used, including some with negative Poisson's ratio. The bending response was investigated and compare d with beam-theory predictions. Most of the cores evaluated had sufficient shear stiffness that the bending compliance was relatively high and dominat ed by the face sheets. Two of the core configurations were ''soft" and exhi bited behavior governed by core shear. The relative dimensions of the cores evaluated in this study were far from those that minimize the weight, beca use of fabrication constraints. The development of an ability to make high- aspect ratio cores is an essential next step reward producing structurally efficient, lightweight microscale beams and panels.