Design of Pressure Actuated Cellular Structures

A novel concept for pressure actuated cellular structures was published by Pagitz et al. 2012 Bioinspir. Biomim. 7. The corresponding mathematical foundation for the simulation and optimization of compliant cellular structures with central cell corner hinges can be found in Pagitz and Hühne 2014 arXiv:1403.2197. The aim of this article is fourfold. First, analytical expressions for optimal material properties of compliant cellular structure are presented. Second, it is shown that, for given target shapes and stiffness requirements, a cellular structure can be either made from a large number of small and highly pressurized cells that consist of a stiff material or from a small number of large and lowly pressurized cells that consist of a soft material. Third, extensions to the previously published numerical model are presented and their application ranges are determined. Fourth, end cap designs for prismatic cells are developed that can withstand substantial differential pressures while being flexible enough to allow large cross sectional shape changes. Notation Ac, At cross sectional area of cell, end cap tendon E Young’s modulus F axial cell side force L cell side length M , M0 bending moment of cell side, at cell corner Mm, Mp cell side bending moment due to end moments, pressure T transverse forces at cell side ends V , V0 volume, initial volume of a single cell, end cap W , W0 section modulus of cell side, at cell corner