Effect of specimen geometry in tensile Hopkinson bars testing

The Spit Hopkinson Pressure Bar (SHPB) apparatus is located in the Strength of Materials Laboratory at the Nanyang Technological University (NTU). There are three common types of SHPB testing techniques. These are tensile, compression and torsion. This report shall focus on tensile SHPB technique. The tensile SHPB technique can be used for testing dynamic stress and strain response of different solid materials at relatively high strain rates in the order of 1000 sec-1. [1] Its theory is based on the propagation of longitudinal pressure waves along the elastic bars. Strain gauges, mounted onto these bars, capture the stress- strain responses which have to be converted to useful, quantifiable data for comparison with existing literatures. The objectives of this the project are compiling detailed ‘idiot guides’ for specimen measurement and verification process as well as SHPB setup and operation procedures, alignment of SHPB by performing empty runs , calibration of SHPB using standardized aluminum alloy specimen Al6061-T6 and comparing results obtained with literature and static test. The project will also look into various problems faced during the course of the experiment and reasons why the experiment cannot continue beyond calibration. Finally, recommendations to improve strain rate in the SHPB equipment as well as quality of experimental results will be proposed.Bachelor of Engineering (Mechanical Engineering