Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Supervisor

Mao, Haojie

Abstract

Small remotely piloted aircraft system (sRPAS) to ground human head impact could cause injuries to the public. Skull fractures and brain injuries have been observed in sRPAS-related impacts, which varied in angles, locations and velocities. This study developed a representative quadcopter sRPAS finite element model and incorporated it with THUMS ver 4.02 50th percentile male and 5th percentile small female models to simulate sRPAS to human head impacts. The simulations were validated with cadaver experiments. The common injury metrics such as head injury criteria (HIC) and brain injury criterion (BrIC) were correlated with head injury-related responses such as skull von Mises stress, brain strain, and strain-based cumulative strain damage measure (CSDM). HIC showed moderate to strong correlations with skull stress. BrIC correlated with brain strains but at weaker correlations compared to the correlations in other impact scenarios such as sports- or auto-related collisions, demanding further investigation. The most damaging impact directions were identified as rear 0 degree for inducing high skull von Mises stress and frontal 58 degree and rear 58 degree for inducing high brain strain. Lastly, this study compared the head and brain responses between different genders under sRPAS impacts and highlighted the higher risks for small female compared to average male.

Summary for Lay Audience

With the increasing usage of small remotely piloted aircraft system (sRPAS), development of a new method to investigate the sRPAS related injury mechanism and assessment of the injury risks are needed. This study mainly focused on using computational techniques (finite element methods) to simulate the impact processes, collected the head kinematics, and calculated injury metrics and parameters. The finite element analysis being applied to sRPAS is a new approach, which systematically considered the objects’ geometries, material properties, contact conditions and impact conditions such as initial positions and velocities.

This thesis study started with the development of a representative quadcopter finite element model and incorporated it with a high biofidelity human model which had complex head and brain structures and detailed meshes. The head center gravity kinematics data were collected and then compared with the data of cadaveric experiments. With validated sRPAS finite element model, the work then progressed to searching injury metrics, which could be used to regulate sRPAS safety for the public. Furthermore, our study identified the most vulnerable impact locations. Finally, our research incorporated developed sRPAS model with small female human model. The head injury responses and risks between different genders were compared with small female potentially subjecting to higher brain injury risks under the same impact conditions as an average male, hence demanding better protection.

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