@inproceedings{hodgins_york_seelecke_2010, title={Electro-mechanical analysis of a deap actuator coupled to a negative-rate bias spring mechanism}, DOI={10.1115/smasis2010-3849}, abstractNote={This paper presents the design and analysis of a Negative-rate Bias Spring (NBS) paired with a Dielectric Electro-Active Polymer (DEAP). A NBS is a bi-stable mechanism with a negative slope region between its two stable configurations. The objective of this work is to demonstrate the increased stroke output of a DEAP actuator when biased by such a bistable mechanism. Possible devices that could use this actuation technology are lightweight, miniature pumps and valves. First, the NBS is mechanically tested and its bi-stable behavior is observed along with the negative slope region between the stable configurations. Then the NBS is coupled with a circular DEAP actuator (to provide the bias force) and is experimentally tested under a variety of loading conditions with a focus on the force and stroke capabilities. The stroke output of the device was approximately 1mm for a range of electrical loading rates (0.1Hz, 1Hz, and 10Hz). The measured force and stroke are then correlated to the force vs. displacement data observed during the mechanical characterization experiments. Additionally, the force vs. displacement behavior of the NBS-DEAP is analytically modeled and showed good comparison with the results.}, booktitle={Proceedings of the ASME Conference on Smart Materials, Adaptive Structures and Intelligent Systems, 2010, vol. 1}, author={Hodgins, M. and York, A. and Seelecke, S.}, year={2010}, pages={315–322} }
 @inproceedings{hodgins_seelecke_2010, title={Mechanical behavior of a bi-stable negative-rate bias spring system}, volume={7644}, booktitle={Behavior and mechanics of multifunctional materials and composites 2010}, author={Hodgins, M. and Seelecke, S.}, year={2010} }
 @inproceedings{york_hodgins_seelecke_2009, title={Electro-mechanical analysis of a biased dielectric EAP actuator}, DOI={10.1115/smasis2009-1441}, abstractNote={Dielectric Electro-Active Polymers (DEAP’s) can achieve substantial deformation (>300% strain) while, compared to their ionic counterparts, sustaining large forces. This makes them attractive for various actuation and sensing applications such as light weight and energy efficient valve and pumping systems. This paper provides a systematic experimental investigation of the quasi-static and dynamic electro-mechanical properties of a commercially available dielectric EAP actuator. In order to completely characterize the fully coupled behavior force vs. displacement measurements at various constant voltages and force vs. voltage measurements at various fixed displacements are conducted. The experiments are conducted with a particular focus on the hysteretic and rate-dependent material behavior. These experiments provide insight into the viscoelastic and electrostatic behavior inherent in DEAP material. Typical operating conditions of the actuator require it to have a biased force, such as a spring. Experiments are conducted to observe the actuators performance under these conditions. The force and stroke capabilities are investigated while the actuator is loaded with different springs and at a variety of pre-stretch levels. The resulting behavior of the spring loaded actuator is then correlated to the viscoelastic effects observed during the electro-mechanical characterization.}, booktitle={SMASIS 2009, vol 1}, author={York, A. and Hodgins, M. and Seelecke, S.}, year={2009}, pages={289–297} }