Tensile Test Lab Report

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Introduction The construction materials course is an essential part of civil engineering as the strength of all structures and constructions depends on the material used. The tension test is one of the laboratories which help students develop their knowledge in this course by practice. During the laboratory a Tinius Olsen Tension Test equipment was used, and the test samples were from low and high carbon steel and timber with grains parallel and perpendicular to the load. Test equipment and materials The test equipment used during the laboratory is one of the Benchtop Materials Testing Machines made by Tinius Olsen. This machine can test different types of materials and it is provided with software which gives the opportunity to users…show more content…
The graphs for Aluminium. Figure 6. The Stress-Strain Graph for Aluminium The shape of the curve in the graph is similar to the graphs for the steel. However, it can be noticed that the maximum load for aluminium is much less than for steel. Consequently, the load at elastic limit and failure load are also small (5.13kN and 3.88kN respectively). The causes of difference of the graphs will be given in Discussion part. The Figures 7-10 illustrate the tension test for timber samples when the load was applied parallel to the grain. From these graphs it is easy to see that the elastic region is very small for timber. In contrast, the plastic deformation takes the bigger region for the large extension. In addition, the specimens break when the maximum load is applied, and it seems that the failure occurs several times. The cause of this behavior is that all grains do not break at one time. The Figures 11-12 show the load-extension graphs for specimens when the load was applied perpendicular to the grain. It can be seen that the failure occurs at small applied load with comparison to other materials. The elastic regions for these specimens are bigger than for samples parallel to the grain. The extension is very small. The calculation of the mean stress, standard deviation, coefficient of variation and characteristic value The mean stress is the arithmetical average of failure
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