Structural Properties

Until now honeycomb core sandwich panels offered the best solution to stiff lightweight design. In a load-bearing application, when a honeycomb core is subjected to bending, its shear stiffness is linearly proportionate to its weight. Other competing core materials such as polymer and metallic foams have non-linear shear stiffness dependence and therefore have proven less desirable for lightweight stiff design. At these low weights the stiffness of foams can be up to ten times less than that of an equivalent weight of honeycomb or Microtruss™ cores.

Pyramidal and Tetrahedral Microtruss™ core configurations have been predicted and experimentally shown to effectively offer the same levels of shear stiffness efficiency as honeycomb-based constructions and are superior to all other sandwich core materials, see Figure 1. All Microtruss™ configurations also possess the added benefits of a 3-dimensional open-cell architecture. This feature of Microtruss™ eliminates many of the inherent difficulties associated with honeycomb sandwich products such as formability, pressure related debonding, corrosion due to moisture entrapment, and complex methods for inspection.

For weight-limited designs, Microtruss™ has attractive shear and compression strength properties on par with the best honeycombs available today (see Figure 2 for a shear strength comparison). Microtruss™ strength properties also substantially exceed those of metal foam products. These unprecedented levels of load support combined with Microtruss™ 3D architecture offer the designer/engineer a new path to creating structures for the most demanding applications while reducing total life cycle costs.