Single member actuation in large repetitive truss structures

Numerical results are presented for the energy required to actuate a single member in three large two-dimensional lattice structures. As expected, the actuation energy, relative to the energy required to stretch a bar, scales with bar stockiness to the power two for a hexagonal lattice, whose behaviour is bending dominated, but is not greatly affected by stockiness for a triangulated lattice, whose response is stretching dominated. For a kagome lattice, however, the relative actuation energy scales with stockiness to the power one. Simple models show that, for the kagome, the attenuation of the deformation with distance from the actuated bar itself depends on the stockiness, and this results in the unexpected energy scaling; they also show that the energy is approximately equally partitioned between bending and stretching. (C) 2003 Elsevier Ltd. All rights reserved.