Universal Testing Machine

A universal testing machine is a device used in materials testing to apply a controlled tensile, compressive or bending load to a specimen and measure how it deforms and eventually fails, producing the stress-strain data that underlies most engineering strength specifications. The Scottish engineer David Kirkaldy built an early large-scale hydraulic testing machine in the 1860s and in 1874 opened Kirkaldy's Testing and Experimenting Works in London, the first commercial laboratory devoted to independently verifying the strength of structural materials such as iron and steel for engineers and shipbuilders. Later machines replaced Kirkaldy's manually read hydraulic ram with screw-driven and, eventually, electronically controlled and recorded loading systems, but the basic universal testing machine, a frame that grips a specimen and pulls, pushes or bends it while recording load against displacement, remains the standard instrument of materials engineering testing.