Figure 1: UTM INSTRON MODEL 5581 ALONG WITH ENVIRONMENTAL CONTROL CHAMBER 3119-407
The specimen is uniaxially compressed and load and deformation are recorded. Compressive stress and strain are calculated and plotted as a stress-strain diagram which is used to determine elastic limit, yield point, yield strength in compression.
Tensile testing provides most information about the mechanical behavior of materials. In this test the material is deformed uniaxially as the load is applied. The load and displacement are recorded using load cell and extensometer respectively. The tensile test result is commonly presented as stress-strain curve as shown in the figure.
Flexure test method measures the behavior of materials subjected to simple beam loading. Maximum stress and maximum strain are calculated for increments of load. Results are plotted in a stress-strain diagram. Flexural strength is defined as the maximum stress in the outermost fiber. In addition, flexural modulus is calculated from the slope of the stress vs. deflection curve if the curve has no linear region.
Instron-5581 is a 50 KN load capacity floor mounting type electro-mechanical testing system. A load transducer (load cell) mounted in series with the specimen, measures the applied load. The load cell converts the load into electrical signals that the control system measures and displays. Using the Extensometer during the test provides the more accurate direct measurement and closed-loop control of specimen displacement. It has a high accuracy and wide frequency response and can be used with metals, rigid thermoplastics and thermosetting plastics exhibiting total strain up to ±100% of the original gauge length. The current UTM is commonly used for static testing in tensile or compression, tensile creep and relaxation (for polymers). Depending upon the test set up additional tests can be performed like shear, flexure, creep, peel, tear, cyclic and bend tests. Picture of the UTM along with the environmental control chamber is shown on the next page.
Bluehill2 software controls Instron testing system for test setup, test
control, data collection, result generation and report preparation. The
software features a graphical user interface, which provides up to four
real time numerical displays (digital and/ analog) of test data as well as
graphs, results table and reports.