Adaptive structures – Soft mechanical approach

Abstract

Since their earliest conceptualization, structures with reconfigurable characteristics contributed to the emergence of an architecture, able to respond and adjust itself to shifting environmental conditions, or time dependent users’ needs. In this respect, the development of tensegrity and scissor-like structures to obtain adaptive capabilities, is primarily based on articulated joints and embedded mechanical actuators, following a hard mechanical approach. Although these systems are usually designed to use a small number of components to achieve maximum shape adjustments, their implementation often causes an increase of unsustainable processes with regard to the number and characteristics of the actuators used and mechanisms complexity, as well as energy-inefficient processes, in terms of both construction and kinetic operation. An alternative soft approach for adaptive structures is proposed in the current paper through an implementation of hybrid cable bending-active members, while the latter replaces multiple local hinges through reversible elastic bending deformations. Through the cables own length modification, these are responsible for the structure deformability and sufficient prestressing of the primary elastic members. Such pliable structures increase the level of design complexity due to the inherent elastic properties of the materials used and their nonlinear structural behaviour during transformation. In demonstrating this, a series of single, coupled and coupled-interconnected cable bending-active system configurations are investigated. Results obtained describe the stress distribution between the structural components during the systems’ form-finding process and load-bearing behaviour.