Localized Rigidification of PCM Envelopes





This is an experimental and computational exploration of structural systems that transform between states of rigidity and flexibility. The goal is to create a link between digital structural analysis, digital design, and physical testing and fabrication, while mitigating the challenges involved in each. The methods used are based on selectively rigidifying structural components in real-time through freezing of phase change materials embedded within flexible materials based on structural topology optimization results. Topology optimization is done using Millipede and Topostruct software to minimize material layout within the design boundary. The abstractions resulting from topology optimization are then used intuitively to design for least compliance (highest rigidity).

For prototypes, flexibility and transparency were two important factors and therefor silicone rubber (Dragon Skin 10 Fast) has been selected that can change based on project by needs and scale. For purposes of freezing, different methods such as pinpoint freezing using highly conductive materials (copper) has been used. The final prototype is built using a robotic waterjet, inspired by branching patterns of heatsink topology and structural topology optimization patterns.


Though the design of responsive, shape-changing interfaces using electricity (use of heat) has been extensively explored, the approach used is unique because it focuses on passive dynamic transitions through material

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Topology Optimization

Topology optimization has been used to visualize and simulate the localized rigidification patterns. The design target is to make a structure stiffer, with the least displacement and strain

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Physical Testing

In order to test mechanical behaviors of ice and ice composites, 4 design iterations were tested (Fig. 24):

Case I includes water filled silicone rubber with an outer

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To obtain an optimized heat transfer system for localized freezing, inspiration was drawn from the two-dimensional topology optimization results of channel layouts obtained for a heat sink design and a

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Facade Application

Historically, igloos have been built using the principle of compression in order to create habitable spaces in cold climates. Using the PCM design strategies in this research, a final product

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Conclusion and Future Work

Some advantages of using this method are saving materials and labor, less assembly time and the opportunity to produce modular components with specific structural properties that can be assembled and

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The author would like to thank Panagiotis Michalatos for his support throughout this research.

Rights and Permissions

Bahadori M., Passive cooling systems in Iranian architecture, Scientific American, 1978, 238, 144–154.

Bornoff, R. and Parry, J. (2015) “An Additive Design Heatsink Topology Identification and Optimization Methodology.” Proceedings of SEMI-THERM Conference, San Jose CA, March 2015.

Craig S., Harrison D., Cripps A., Knott D., BioTRIZ Suggests Radiative Cooling of Buildings Can Be Done Passively by Changing the Structure of Roof Insulation to Let Longwave Infrared Pass, Journal of Bionic Engineering 5, 2008, 55−66.

Heibeck, F.; Tome, b.; Della Silva, C.; Ishii, H (2015) “UniMorph-Fabricating Thin-Film Composite for Shape-Changing Interfaces.

O’Connor, C. M. & Adams, J. U., Essentials of Cell Biology, Cambridge, MA: NPG Education, 2010.

Squishy robots: http://news.mit.edu/2014/squishy-robots-0714.


All photos and diagrams are produced by the author unless referenced under the photos.