Rapid testing of tensile properties for miniature metal specimens

• Main Author: Hew, Wen Feng
• Other Authors: Sridhar Idapalapati
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Small punch test; Material testing techniques; Finite element analysis; Abaqus; Anisotropic
• Online Access: https://hdl.handle.net/10356/177825
• Institution: Nanyang Technological University

This report explores the feasibility of converting force-displacement data obtained from a small punch test (SPT) into mechanical properties, such as ultimate tensile strength, and uniform elongation, typically obtained from a tensile test. The SPT has become increasingly popular in recent years due to its simplified sample preparation process and reduced material volume requirements. Past literature studies have employed the use of empirical relationships to correlate SPT properties with tensile properties. This method has proven to be reasonably accurate for existing recorded materials. However, for new materials without prior data, empirical relationships may not be applicable without first conducting a tensile test. Moreover, while most studies on correlating SPT results with tensile test results are done for isotropic materials, limited research is available for anisotropic materials, such as those produced by Additive Manufacturing, a production method that has gained much popularity in recent years. Hence, there is an interest in finding a rapid material testing method for this group of materials to determine their tensile properties. This study utilized the modified version of Hollomon’s power-law equation, the Swift equation, in conjunction with finite element analysis (FEA) software (Abaqus®) to predict mechanical properties such as yield strength, ultimate tensile strength (UTS), and uniform elongation from SPT. The materials focused on were AlSi12, C465+TiN 1%, Al6061, and IN738LC, with AlSi12, C465+TiN 1% and IN738LC being additively manufactured. The first round of correlations does not provide good tensile estimation for most specimen. A new method of describing plastic properties into the FEA simulation was identified and subsequently employed, resulting in an enhancement of the predicted tensile results for most materials. However, AlSi12 displayed discrepancies in its predicted behaviour despite the implementation of this new approach. The study's findings hold implications for future material testing, offering a rapid and cost-effective analysis of new miniature metal specimens.