A universal testing machine is used to subject a material sample or structure to either tension ("stretch it") or compression ("crush it") for the purposes of experimentally determining certain engineering properties or characteristics. These properties generally deal with the yield strength of a material, ultimate or failure strength or a material or structure, or the stiffness and ductility of a material.
Materials samples may be tested for several reasons:
- to inspect the batch quality and consistency (e.g. concrete)
- to determine whether a given sample meets ASTM or other standards for its marked grading
- to determine properties of an unknown material
- and many more...
Structures or scale models of structures may be tested for several reasons:
- It is cheaper and less risky to test a scale model of a design than it is to build a full scale prototype only to find out that the design was flawed.
- Controlled testing conditions provide the desired data in the range of design loadings without risking human injury and liability.
- Testing and certification of many designs is required before a full scale structure may be constructed.
- and many more...
The ENGR 242 Engineering Materials course, among others, makes frequent use of the universal testing machines in the Materials Testing Laboratory. Students explore mechanical properties for a variety of materials, the relationships between load, strain, and deflection in beams, tension members, and other structural elements, and the performance of structural connections.
Three different universal testing machines are available for use in the Materials Testing Laboratory. The largest machine has a load capacity of 200,000 lb. and is used to test concrete compression specimens, reinforced concrete, structural steel, and aluminum alloy beams, structural connections, and tension members. The newest machine is an Instron electromechanical testing machine with a load capacity of 30,000 lb. This machine offers precise control over rate of load application or rate of deformation, and full computer test control, data acquisition, and data analysis.