AN APPARATUS FOR TENSILE AND FATIGUE TESTING OF METALLIC MATERIALS INVOLVING MINIATURE SPECIMENS

Mechanical testing under tensile and fatigue loading is ubiquitous. Such testing often requires expensive equipment and peripherals. During the development stages of any new material or manufacturing processes, it is often desired to perform quick evaluations to optimize the material composition or the manufacturing process parameters to achieve the desired properties. To address this requirement, this paper designs, develops, and deploys a low-cost custom testing apparatus capable of performing both tensile and fatigue testing to investigate the failure characteristics of a candidate material system, e.g., cold-rolled Al7075-T6. The apparatus consists of a linear actuator, a load cell, a polycarbonate sleeve, and a data acquisition system. The apparatus is additionally integrated with a high-speed video imaging system to investigate the failure evolution. The experiments are performed through a custom MATLAB^® code. The resulting data are processed to extract the relevant mechanical properties such as the yield strength, the ultimate tensile strength, and the fatigue life. The results demonstrate that the apparatus can reliably characterize the tensile and fatigue properties of Al7075-T6. Throughout its use, the apparatus is found to be robust, resilient, and easy to assemble/disassemble. In conclusion, this apparatus can serve as a low-cost testing equipment to understand tensile and fatigue failure characteristics of metallic specimens during the qualification stages.