Whiplash is a neck injury caused by the sudden differential movement between the head and torso. Whiplash injuries are most commonly reported as a consequence of rear impacts in car accidents. They are regarded as minor injuries, but can still lead to long-term disablement and discomfort in the neck. Whiplash injuries can be mitigated by better car seat designs. For this purpose, head restraint geometry must be improved first, and then the dynamic performance of the whole seat must be assessed at all crash seventies. A biofidelic human-body model is a key requirement in designing whiplash mitigating car seats. This thesis presents the development of a 50th percentile male multi-body human model and several energy absorbing car seat designs. The human-body model is specifically designed for rear impact and validated using the responses of seven volunteers from Japanese Automobile Research Institute (JARI) sled tests, which were performed at an impact speed of 8 kph with a rigid seat and without head restraint and seat belt. A generic multi-body car seat model is also developed to implement various seatback and recliner properties, anti-whiplash devices (A WDs) and head restraints. Using the same driving posture and the rigid seat in the JARI sled tests as the basic configuration, several anti-whiplash seats are designed to allow different types of motion for the seatback and seat-pan. The major findings of this research are: -The human-body model simulates the effects of muscle contraction and its overall response is superior in comparison to the currently used models and dummies. -A criterion called the S-shape index (SSI) is developed based on the intervertebral angles of the upper and lower cervical spine. -The car seat design concepts are able to control and use crash energy effectively with the aid of anti-whiplash devices for a wide range of crash seventies. -In order to reduce whiplash injury risk, this study advocates energy absorbing car seats which can also provide head restraint contact as early as possible.

Blast-induced mild traumatic brain injury (BImTBI) is one of the most common causes of traumatic brain injuries. BImTBI mechanisms are not well identified, as most previous blast-related studies were focused on the visible and fatal injuries. BImTBI is a hidden lesion and long-term escalation of related complications is considered a serious health care challenging due to lack of accurate data required for early diagnosis and intervention. The experimental studies presented in this thesis were performed to investigate aspects of blast shock wave mechanisms that might lead to mild traumatic brain injury. A compressed air-driven shock tube was designed and validated using finite element analysis (FEA) and experimental investigation. Two metal diaphragm types (steel and brass) with three thicknesses (0.127, 0.76, and 0.025mm) were utilized in the shock tube calibration experiment, as a new approach to generate shock wave. The consistency of generated shock waves was confirmed using a statistical assessment of the results by evaluating the shock waves parameters. The analysis results showed that the 0.127mm steel diaphragm induces a reliable shock waveform in the range of BImTB investigations. Evaluation of the shock wave impacts on the brain was examined using two sets of experiments. The first set was conducted using a gel brain model while the second set was performed using a physical head occupied with a gel brain model and supported by a neck model. The gel brain model in both the experimental studies was generated using silicone gel (Sylgard-527). The effects of tested models locations and orientations with respect to the shock tube exit were investigated by measuring the generated pressure wave within the brain model and acceleration. The results revealed that the pressure waveform and acceleration outcomes were greatly affected by the tested model orientations and locations in relation to the path of shock wave propagation. / Thesis / Doctor of Philosophy (PhD)

The challenges of measuring speech signals in the presence of a strong background noise cannot be easily addressed with traditional acoustic technology. A recent solution to the problem considers combining acoustic sensor measurements with real-time, non-acoustic detection of an aspect of the speech production process. While significant advancements have been made in that area using low-power radar-based techniques, drawbacks inherent to the operation of such sensors are yet to be surmounted. Therefore, one imperative scientific objective is to devise new, non-invasive non-acoustic sensor topologies that offer improvements regarding sensitivity, robustness, and acoustic bandwidth. This project investigates a novel design that directly senses the glottal flow waveform by measuring variations in the electromagnetic properties of neck tissues during voiced segments of speech. The approach is to explore two distinct sensor configurations, namely the“six-element" and the“parallel-plate" resonator. The research focuses on the modeling aspect of the biological load and the resonator prototypes using multi-transmission line (MTL) and finite element (FE) simulation tools. Finally, bench tests performed with both prototypes on phantom loads as well as human subjects are presented.