Contents Introduction Sample x results Sample y results Elasticity and Elastic Limit Yield Point and Plasticity Ultimate Tensile Strength Stiffness Ductility Brittleness Hooke's Law Young's Modulus Conclusion Sample x graph Sample y graph Sample z graph List of references Page 2 Page 3 Page 4 Page 5 Page 5 Page 6 Page 6 Page 7 Page 7 Page 8 Page 8 Page 9 Page 11 Page 12 Page 13 Page 14
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University No. 11365048
The Tensile Test I have been provided with laboratory results from tensile tests carried out on 3 samples of materials x, y and z. My task is to use this data to determine the values of modulus of elasticity, limit of proportionality, ultimate tensile strength and other important facts about each material. I will examine the behaviour of each sample under tensile load by means of stress-v's-strain tables and graphs, then identify each material. In order to calculate the value of stress, we must first determine the cross sectional area (CSA) of each material tested. Each sample is of rectangular cross section 20mm by 1mm. CSA = 20mm x 1mm CSA (m^2) = (20x10^-3) x (1x10^-3) = 20 x 10^-6 m^2 or = 0.00002 m^2 I can now use the CSA together with the test results I have been provided with to calculate the instantaneous stress and strain values of each sample after each tensile load is applied using the following formulae: Stress (σ) = Force (F) / CSA Strain (ε) = Extension (x) / Original Length (L) As an example, I will show my calculations of the stress and strain values for the first load applied on test sample x, then I will display the remainder of my results in tables. σ = F / CSA = 1x10^3 / 20x10^-6 = 50x10^6 Pa ε (%) = (x / L) x 100 = (0.48 / 375) x 100 = 0.128%
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University No. 11365048
Results for sample x length 375mm CSA of 20x10^-6 m^2 Load Applied (Kn) Extension (mm) Stress (MPa) Strain (%)
1.0 2.0 3.0 4.0 5.0 6.0 7.0 7.5 8.0 8.5 8.3 8.0 7.0 6.1
0.48 0.60 0.70 0.80 0.85 0.95 1.27