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Development, Classification and Biomechanical Applications of Nano-Composite Piezoresponsive Foam
Başlık:
Development, Classification and Biomechanical Applications of Nano-Composite Piezoresponsive Foam
Yazar:
Merrell, Aaron Jake, author. (orcid)0000-0002-1155-176X
ISBN:
9780438046337
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (140 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: David T. Fullwood Committee members: Anton E. Bowden; Steven K. Charles; Brian A. Mazzeo; Matthew K. Seeley.
Özet:
This dissertation focuses on the development of and applications for Nano-Composite Piezoresponsive Foam (NCPF). This self-sensing foam sensor technology was discovered through research in a sister technology, High Deflection Strain Gauges (HDSG), and was subsequently developed with some of the same base materials. Both technologies use nano and micro conductive additives to provide electrically responsive properties to materials which otherwise are insulative. NCPF sensors differ from HDSGs in that they provide a dual electrical response to dynamic and static loading, which is measured through an internally generated charge, or a change in resistance. This dissertation focuses on the development of the dynamic or piezoresponsive aspect of the NCPF sensors which tends to have more consistent electrical response over a larger number of cycles.
The primary development goal was to produce a sensor that was accurate, while providing a consistent, repeatable response over multiple impacts. The hypothesized electric generation is attributed to a triboelectric interaction between the conductive additives and the polyurethane foam matrix. This hypothesis was validated by examining different conductive additives with varying loading levels and specific surface areas while accounting for other design considerations such as the electrode used to harvest the response. The results of this analysis support the triboelectric model and point to carbon or nickel-based additives for optimal performance. The NCPF response measured by digital signal acquisition devices is directly dependent upon its input impedance. Increased input capacitance has a negative effect on the signal, however, higher input resistance has a positive linear correlation to voltage. Other considerations that affect the electrical response include the temperature and humidity in which the sensor is used and result in a scaled electrical response.
NCPF sensors are ideally suited for use in systems which benefit from impact energy attenuation while measuring the same. This work demonstrates how the NCPF sensors can be used to detect severity and location of impacts in systems with multiple sensors (football helmets), and those with one continuous sensor (carpets). When NCPF sensors were used in a football helmet the impact severity and location of impact was accurately identified. NCPF sensors provide the benefit of simplified design by replacing existing foam while providing a direct measure of the forces. Additional research was conducted on the changes in material properties, specifically how it affects the foam structure's ability to absorb energy in quasi static loading scenarios. NCPF sensors are demonstrated as viable tool to measure many different biomechanical systems.
Notlar:
School code: 0022
Tüzel Kişi Ek Girişi:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(679830.1) | 679830-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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