Engineering material - Essay Example

The central part of the specimen possesses reduced cross-sectional area than the end parts. The reduced gauge ensures that the highest stresses occur within the gauge, and not near the grips of the load frame, preventing strain and fracture of the specimen near or in the grips (Fabila 2010). Incremental application of the tensile load to the specimen and its corresponding extension are recorded and plotted by a computer in the form of a load versus elongation graph. This graph is converted into an engineering stress versus engineering strain graph, which is later used to calculate material properties such as yield strength, Young’s modulus, ultimate tensile strength, resilience, and toughness of material.

The experiment was conducted on specimens made of Mild Steel (Grade 250), Aluminium 6061, Copper, and Brass. All test specimens had an initial gauge length of 25 mm. All other dimensions of specimens are given below: Each specimen was measured using the calipers to determine the diameter and cross section. A gauge length was determined and scribed into the specimen so the distance between two marks could be measured after the tensile test was completed (Fabila 2010). The specimen was securely placed into the jaws of the Instron load frame so that it was equally spaced between the two clamps (Fabila 2010).

The axial and transverse extensometers were attached to the reduced gauge section of the specimen. Care was taken to ensure that the axial extensometer was set correctly, and the transverse extensometer was across the complete diameter of the specimen (Fabila 2010). The test with each specimen continued until fracture. After that, the specimen was removed, and the equipment was reset for the next test. The results of the uniaxial test were used to calculate material properties using the formulas provided below.

The results of the tensile tests