UC San Diego

High strain rate testing of specimens within a split Hopkinson pressure bar (SHPB) is a well-established experimental technique used to quantify the compressive properties of materials in high impact events. The aim of this thesis is to investigate high strain rate tensile testing of materials utilizing a modified Hopkinson pressure bar system containing a tension yoke that deforms a test specimen by impacting the yoke strike plate and converting the incident compression wave into tension loading through the specimen. Credence towards the proposed design is built utilizing various finite element benchmark models and verification against the principles of SHPB systems is conducted using computational analysis to quantify the feasibility and performance of the system. Results show that the strain response in the Hopkinson pressure bar shows a strong correlation to the strain response in the test specimen, as assessed via comparison of peak forces and observing relatively low difference between the two quantities. Following this, effects of dispersion are explored further by modifying the impacting pulse shape and comparing results between different pulse shapes. Final stages of analysis reveal that momentum of the tension yoke largely affects the strain response of the tensile specimen relative to the applied pulse. However, the strong correlation of the force pulse developed within the tensile specimen and the force pulse transmitted into the Hopkinson bar remains very consistent, showing the potential of the proposed apparatus design to be used as a functional experimental system for converting impact into high strain rate tensile loading.