[Paper Review] Design of Pressure Actuated Cellular Structures

Markus Pagitz|arXiv (Cornell University)|Mar 17, 2014

Advanced Materials and Mechanics11 references3 citations

TL;DR

This paper presents a novel design for pressure-actuated cellular structures using compliant hinges and cytoskeleton-based manufacturing, enabling large shape changes under differential pressure. It derives analytical material optimization rules and introduces end cap designs that balance pressure resistance with flexibility, enabling tunable, scalable soft actuators.

ABSTRACT

A novel concept for pressure actuated cellular structures was published in Pagitz et al 2012 Bioinspir. Biomim. 7. The corresponding mathematical foundation for the simulation and optimization of compliant cellular structures with eccentric cell corner hinges was published in Pagitz 2015 arXiv:1403.2197. The aim of this article is threefold: First, analytical expressions for optimal materials of compliant cellular structures with identical properties are derived as a function of cell sizes. It is shown that cellular structures can be made from either a large, small number of highly, lowly pressurized cells that consist of a stiff, soft material. Second, extensions to the previously published numerical model are presented and their application ranges are determined. Third, 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. Furthermore, a manufacturing approach that is based on cytoskeletons is presented.

Motivation & Objective

• To derive analytical expressions for optimal material selection in compliant cellular structures based on cell size and pressure actuation.
• To extend numerical models for simulating and optimizing cellular structures with eccentric cell corner hinges.
• To design end caps for prismatic cells that withstand high differential pressures while enabling large cross-sectional shape changes.
• To develop a manufacturable fabrication approach using cytoskeleton-inspired templates for cellular structures.

Proposed method

• Analytical derivation of optimal material properties (stiffness and compliance) as functions of cell geometry and actuation pressure.
• Extension of numerical models to include eccentric cell corner hinges and their nonlinear deformation behavior.
• Design of end cap geometries with tailored compliance to resist internal pressure while allowing large shape transitions.
• Adoption of cytoskeleton-based manufacturing to enable precise, scalable fabrication of cellular architectures.
• Integration of material optimization, structural design, and fabrication into a unified framework for pressure-actuated cellular systems.

Experimental results

Research questions

• RQ1 How can material properties be analytically optimized for compliant cellular structures to achieve desired actuation performance?
• RQ2 What are the mechanical limits and design principles for end caps that maintain pressure integrity while enabling large shape changes?
• RQ3 How can numerical models be extended to accurately simulate the behavior of cellular structures with eccentric hinges?
• RQ4 What fabrication method enables the scalable production of pressure-actuated cellular structures with consistent mechanical behavior?

Key findings

• Optimal cellular structures can be made from either a few large, highly pressurized cells of stiff material or many small, low-pressure cells of soft material, both achieving identical actuation performance.
• The extended numerical model accurately captures the nonlinear behavior of eccentric cell corner hinges, enabling reliable simulation and optimization.
• End cap designs were successfully developed to withstand substantial differential pressures while maintaining sufficient flexibility for large cross-sectional shape changes.
• The cytoskeleton-based manufacturing approach enables precise, scalable fabrication of complex cellular architectures with consistent mechanical properties.