Tensile Test Lab Report Essay

SHORT REPORT/LOG SHEET Table 1. Tensile testing results Testing Laboratory MSE Undergraduate Lab Room 6 Materials used Polystyrene (PS) High-density Polyethylene (HDPE) Aluminium Alloy (Al) Specimen Geometry Dumbell shape Test Temperature (°C) 22 Loading rate (mm/min) 2 Nominal dimensions (mm): width, thickness, gauge length PS: 12.01, 1.99, 60 HDPE: 12.04, 3.00, 60 Al: 12.05, 2.03, 60 Mat./ Spec. Width, mm Breath, mm Pmax, N , MPa , MPaL0, mm Lf, mm Af, mm2 %EL %AR PS 12.01 1.99 1016.64 42 42.537 61.902 60.000 23.900 3.170 0 Al 12.05 2.03 3278.13 60 134.01 60.000 72.886 13.769 31.48 43.71 HDPE 12.04 3.00 881.313 18 24.400 60.000 291.72 20.332 386.2 86.34
1. Plot the strain-stress curve of the three specimens using the saved raw data. Discuss

It then moves on to non-uniform plastic deformation as necking starts to occur and when it reaches the fracture stress, the aluminium alloy experiences a ductile fracture.Aluminium alloy experience ductile fracture as it has high tensile strength, which holds the metal atoms together resisting deformation, hence when it has reached its unbearable tensile stress, the aluminium alloy would then fracture. Aluminium alloy has the highest Young's modulus compare to the other 2 specimens. -40-200204060801001201401600 0.05 0.1 0.15 0.2 0.25Stress (MPa)StrainoffsetAlAlloy
Polystyrene (PS) Polystyrene undergoes elastic deformation with little plastic deformation before experiencing a brittle fracture as seen on the graph. This is due the high young's modulus polystyrene has, as it has a benzene-ring side group that forms strong intermolecular van der waal's forces of interaction, however, that restricts polymer chain from rotating, hence when high amount of stress is applied to it, it would fracture, instead of sliding away to form new bonds with neighbouring atoms. -1001020304050600 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04Stress