Princeton University Library Catalog
- Siu, Sabrina [Browse]
- Senior thesis
- Adriaenssens, Sigrid [Browse]
- Princeton University. Department of Civil and Environmental Engineering [Browse]
- Class year:
- 95 pages
- Restrictions note:
- Walk-in Access. This thesis can only be viewed on computer terminals at the Mudd Manuscript Library.
- Summary note:
- Due to a global increase in energy consumption from an expanding population,
research into ways to reduce energy use in buildings is increasing in importance.
Proper daylighting strategies, when correctly integrated into building design, can
have a major impact in the building energy balance. Proper daylighting can result in
the decrease of artificial light energy use as well as lower heating due to solar radiation.
In most structures, however, sun shading, an integral part of every building, still relies
on ine cient shading methods and can be vastly improved. Alternate methods of sun
shading employing adaptive structures can be used for improvement.
This thesis explores how large strain characteristics of Dielectric Electroactive
Polymers (Dielectric EAPs) could be exploited for adaptive shading structures through
the experimental and numerical study of an elementary Dielectric Elastomer Minimum
Energy Structure (DEMES). A DEMES is composed of a pre-stretched dielectric
elastomer adhered to an inextensible compliant frame. In the DEMES studied in this
thesis, the tension in the stretched membrane causes the frame to curl up, and when
the structure is activated (voltage application), the frame returns to its initial planar
state, forming a useful bending actuator.
For the experimental study, a series of physical models were fabricated and successfully
tested through a range of applied voltages. Experimental tests were also
validated through a comparison with O'Brian et al. (2009). In addition, further investigation
was conducted into the behavior of isotropically stretched DEMES. The
isotropic behavior was identified to act similarly to different stretch ratios and produce
similar effects. Physical models were also employed as a reference for the numerical
For the numerical study, a modified dynamic relaxation algorithm was employed
to model the DEMES. Dynamic relaxation is an iterative numerical method used to
find a static equilibrium of a structure. The modified algorithm is an improvement
upon existing dynamic relaxation formulations incorporating novel bending and clustering
elements. It allowed for the study of key parameters such as the stiffness ratio
between the frame and the membrane. Moreover, comparison with the physical models
showed that the dynamic relaxation model correctly reflects the behavior of the
studied DEMES. Finally, although the dynamic relaxation model is limited by approximated
input values and mesh issues, the model is found suitable for future use
in the design of adaptive DEMES shading systems.