Innovative Testing Machines and Methodologies for the Mechanical Characterization of Materials

This paper is focused on the development of innovative testing machines and methodologies for the characterization of materials in working conditions similar to those found in mechanical processing of materials. Special emphasis is given to the design, fabrication, and instrumentation of a flexible drop weight testing machine, an electromagnetic compressive Hopkinson bar, and an electromagnetic cam-driven compression testing machine that are capable of performing the mechanical characterization of materials under medium- and high rates of loading. The fundamentals of plastic flow in selected forming and cutting processes are utilized to assess the validity and reliability of the proposed testing machines and associated experimental methodologies. Experimental data with technical pure Lead allows understanding the combined influence of strain, strain rate, and strain rate versus strain loading paths in the overall stress response of the materials. Results also show that the new proposed electromagnetic cam-driven compression testing machine equipped with a root type or logistic cam profile can successfully replicate the operating conditions of the two other testing machines.