Three DSSL researchers were recognized at the 2015 College of Engineering Eminence Awards banquet for their excellence in research and teaching. Congrats Ryan, Chase, and Cesar!
Dr. Anton has been awarded a Faculty Research Grant for 2015-2016 from the Office of Research at Tennessee Tech titled “Integrated Sensing and Energy Harvesting in Total Knee Replacement Implants.“
Brooke Wilson successfully defended her Masters of Science degree in Mechanical Engineering entitled “Modeling and Experimentation for Evaluation of Piezoelectric Sensors for In-Vivo Monitoring” on April 16, 2015. Congratulations Brooke!
Abstract:
The knee replacement is the second most common orthopedic surgical intervention in the United States, but currently 1 in 5 knee replacement patients are not satisfied with their level of pain reduction one year after surgery. It is imperative to make the process of knee replacement surgery more objective by developing a data driven approach to ligamentous balance, which increases implant life. In this work, piezoelectric materials are considered for both sensing and energy harvesting applications in the total knee replacement implants. This work aims to embed piezoelectric material in the polyethylene tibial component of a knee replacement unit to act as sensors that will aid in the alignment and balance of the knee replacement by providing intraoperative feedback to the surgeon. Postoperatively, the piezoelectric sensors can monitor the structural health of the implant in order to perceive potential problems before they become bothersome to the patient. Specifically, this work will discuss the use of finite element modeling coupled with uniaxial compression testing to prove that piezoelectric stacks can be utilized to harvest sufficient energy to power the sensors needed for this application. This work will show that energy on the order of 20 J can be generated over the course of a day.
Chase Ray successfully defended his Masters of Science degree in Mechanical Engineering entitled “Piezoelectret Foam in a Multilayer Stack Configuration for Vibration Energy Harvesting” on April 14, 2015. Congratulations Chase!
Abstract:
Electronic devices are high demand commodities in today’s world, and such devices will continue increasing in popularity. Currently, batteries are implemented to provide power to these devices; however, the need for battery replacement, their cost, and the waste associated with battery disposal present a need for advances in self- powered technology. Energy harvesting technology has great potential to alleviate the drawbacks of batteries. In this work, a novel piezoelectret foam material is investigated for low-level vibration energy harvesting. Specifically, piezoelectret foam assembled in a multilayer stack configuration is explored. Modeling and experimentation of the stack behavior when excited in compression at low frequencies are performed to investigate piezoelectret foam as a multilayer energy harvester. An examination of modeling piezoelectret foam as a stack with an equivalent circuit is made following recently published work and is used in this study. Two 20-layer prototype devices and a 40-layer prototype device are fabricated and experimentally tested via harmonic base excitation. Electromechanical testing is performed by compressing the foam stacks to obtain output electrical energy; consequently, allowing the frequency response between input mechanical energy and output electrical energy to be developed. Modeling results are compared to the experimental measurements to assess the fidelity of the model at resonance. Lastly, energy harvesting experimentation in which the devices are subject to harmonic base excitation at the natural frequency is conducted to determine the ability of the piezoelectret foam stack to successfully charge a capacitor. For a 20-layer stack, a 100 F capacitor is charged to 1.45 V in fifteen minutes, and produces a peak power of 0.45 W. A 40-layer stack can charge a 100 F to 1.7 V in iffteen minutes, and produce a peak power of 0.89 W.
DSSL researchers Chase Ray and Cesar Contreras received Best Poster Awards at the 2015 TTU Student Research Day. Chase presented a poster titled “Evaluation of Piezoelectret Foam in Stack Configuration for Low-Level Vibration Energy Harvesting” and Cesar presented a poster titled “Finite Element Modeling of Embedded Piezoelectrics in Knee Replacements Bearings.” Congratulations Chase and Cesar!
DSSL researchers Brooke Wilson, Chase Ray, April Parkison, and Cesar Contreras presented posters at the 2015 TTU Student Research Day on April 9, 2015. The event is an effort to emphasize the significance of research in postsecondary education; and to recognize the diverse areas of research unique to the different disciplines. Participants from all colleges in the university are welcome to present their research.
