Designing a data acquisition system for a split hopkinson pressure bar

Abstract

Senior students are always challenged to apply their engineering knowledge and research skills gained from an engineering curriculum toward design and implementation of challenging senior design projects. Split Hopkinson Pressure Bar (SHPB) is an apparatus that is used to study materials behavior under high speed deformation, where strain rate is very high. Hopkinson bars are usually custom made based on the needs of customers, who are mostly researchers in universities or research labs. In this work, in a form of a senior design project, the authors provided learning opportunities for engineering students to design a data acquisition system for a small size split Hopkinson pressure bar previously designed by former students. The objectives of this project are to engage a team of students 1) to design a data acquisition system using National Instrument hardware and Labview to collect strain data during high speed deformation testing 2) to design a data processing program to process the strain data collected to stress-strain graph 3) to conduct a number of high speed deformation material testing to validate the performance of the data acquisition system designed. Students implemented the fundamentals of instrumentation, graphical programming, computational methods and solid mechanics to design the data acquisition system for a SHPB. A working prototype of the data acquisition system is integrated and tested. Preliminary tests demonstrate that the performance of the system is as desired. In this paper, the authors elaborate on how the students have utilized the engineering knowledge acquired throughout the course to design and develop the data acquisition system for the Hopkinson Split Pressure Bar and thus the educational gains achieved.