Development and performance evaluation of a multi-functional mechanical testing machine

The design and performance evaluation of a 30 kN mechanical testing machine with capacities for room temperature and hot tensile and compression testing was performed. The design philosophy, material selection, and construction strategy were based on the functions and properties of the materials and control systems, local availability, cost considerations, and ease of assembly and decoupling of the parts. Simulation studies were conducted to optimize the design, loading capacity, and specimen dimensions and configurations. The loading mechanism was by a hydraulic system and a loading frame was constructed to house the hydraulic loading, specimen holding, and heating band systems. Testing to ascertain the performance of the machine using aluminum 6063 alloy samples was preceded by load cell and extensometer calibration of the machine. From the performance evaluation, the UTS and percent elongation values for room temperature (25 C-degrees) tensile test (446-454 MPa and 28.3-28.7%) hot tensile tests at 250 C-degrees (232-233 MPa and 36.3-36.7%), room temperature compression test (439-518 MPa and 32.7-33%), and hot compression test at 250 C-degrees (226-233 MPa and 34-35%), were found to be largely reproducible and values were within the range reported in literature for Aluminum 6063 alloy. The softening mechanisms dominant at elevated temperatures ensured that the strain hardening effect was minimal, which is the reason for the superior percent elongation but lower UTS values for tensile and compression tests performed at 250 C-degrees.