No abstract

Theoretical studies have indicated that truss core panels with a tetragonal topology support bending and compression loads at lower weight than competing concepts. The goal of this study is to validate this prediction by implementing an experimental protocol that probes the key mechanical characteristics while addressing node eccentricity and structural robustness. For this purpose, panels have been fabricated from a beryllium-copper alloy using a rapid prototyping approach and investment casting. Measurements were performed on these panels in flexure, shear and compression. Numerical simulations were conducted for these same configurations. The measurements reveal complete consistency with the stiffness and limit load predictions, as well as providing a vivid illustration of asymmetric structural responses that arises because the bending behavior of optimized panels is dependent on truss orientation. Ó

No abstract

No abstract

No abstract

No abstract

Kagome truss plates have properties that suggest they should be uniquely effective as an actuation plane for sandwich plates: a Kagome truss plate has in-plane isotropy, optimal stiffness and strength, and its truss members can be actuated with minimal internal resistance. In this paper, sandwich plates are studied that are comprised of one solid face sheet and one actuated Kagome face sheet joined by a pyramidal truss core. Various aspects of the actuation behavior of these plates are investigated, including internal resistance and strains resulting from actuation and efficiency of actuation. Single and double curvature actuation modes are investigated. Contact is made with analytic results for actuation modes with long wavelength.

We present results from an experimental and numerical investigation on the compression, and consequent buckling, of a slender rod constrained inside a horizontal cylinder. An experimental model system is developed to systematically study the sequence of instabilities from straight-to-sinusoidal and sinusoidal-to-helical configurations. We quantify the associated buckling loads as a function of the radial clearance between the rod and cylindrical constraint. These results are compared to existing theoretical predictions. While good agreement is obtained for large values of the radial clearance, significant deviations are found when the geometric imperfections of the setup are comparable to the radial clearance. Due to this imperfection sensitivity, the critical buckling loads can be reduced significantly by up to a factor of three. The findings from this model system can be applied to practical applications across a range of length scales due to the geometric (rather than material) nonlinearities involved in the deformations of rods.