Date of Award
The Projectile Professionals were tasked with designing a testing apparatus to test the effectiveness of stab resistant material. The requirements and standards for this were provided by the NIJ and distinguished university professor, Dr. Nassersharif. Design specifications were established for the problem and research was done on the existing testing method via patent and literature searches. Each member of the Projectile Professionals was responsible for creating thirty design concepts. The proposed designs were then evaluated to make sure that the NIJ standards were being achieved. Engineering analysis using a popular method developed in Japan called QFD (Quality Function Deployment) was performed to transform the design specifications of the customer into engineering characteristics for the product in order to compare each concept.
The Projectile Professionals’ testing device will be compressed air powered which is prefilled to a specific pressure reading allowing adequate energy levels to be generated. A PVC barrel which houses the projectile is attached to the compressed air tank. A trigger operated solenoid valve is to release the air built up behind the projectile sending it down the barrel striking the armor at the opened end. This system is mounted onto a test bench that can have easy mobility as well as support the apparatus. The projectile behaves as a dual-mass system coupled with dampening foam so that the impact energy is delivered to more accurately mimic the action of a human hand stab. Another target that must be achieved is striking the armor at 90 degrees as well as 45 degrees using an adjustable padded backstop.
Overall after the concept generations were completed, the Projectile Professionals were able to pick an optimal design to move forward with. A proof of concept was generated and presented to faculty and engineering students. The new and improved design was discussed and settled upon. The team went to work right away putting together the new apparatus to begin gathering data. With the apparatus being complete the team used a high-speed camera to calculate the velocity right before impact which in turn a correlation between energy and pressure was created. These findings were presented to faculty and students for the final build and test review. Overall, the team did achieve solving the problem statement given.
Magistri, Parker; Paolino, Steven; de la Rosa, Arlis; and Odell, Kevin, "Variable Force Dynamic Stabber" (2019). Mechanical Engineering Capstone Design Projects. Paper 55.