Dyanmic tensile test rig

• Main Author: Tan, Jun Hua
• Other Authors: Lu Guoxing
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60219
• Institution: Nanyang Technological University

A typical tensile test rig makes use of the principle of a Hopkinson pressure bar to determine material properties of a specimen at high strain rate. The principle has been evolving over the years, from a single bar to split bar design. Good data processing equipment and appropriate strain gauges are essential to obtain accurate data used to determine material properties. This report focuses on two-bar setup, namely incident bar and transmission bar. By striking the incident bar, a tensile force is generated on the specimen held between the two bars. The waves generated along the bars during experiment would be detected by strain gauges and captured by data processing equipment for evaluation. The strain gauges will be connected to a Wheatstone bridge which is connected to data processing equipment. Wheatstone bridge was used for temperature compensation as well as eliminates the strain components. This setup is essential in obtaining an accurate data. Specimen stress-strain properties could be obtained by obtaining the strains in the two bars and the accuracy of the data depends on the setup which gives only 1-dimensional wave along the bars, therefore a sufficiently long bar is essential to achieve it. The experimental result shows similar graph as of obtained from the source externally. Thus, the setup is able to determine the material properties of the specimen just like any product available in the market. However, there is still room for improvements, and it will be further discuss in the report.