Question

ENGE1001 - Deflection of Beams Objective: To verify the relationship between load and deflection for a simply supported beam with a single concentrated central load. (Note: You may find other objectives after doing the experiment) Apparatus: Knife edge supports, dial gauge, weights and weight carrier. Method: • • 1 Mild steel bar • 1 Brass bar 25.4mm x 4.76mm 25.4mm x 6.35mm Set up each beam in turn centrally on knife edge supports near the ends of the beam. Locate the dial gauge centrally between supports and set to zero. • Apply loads in 200 gram increments to 1600 grams, noting deflections. • Repeat while removing loads. NOTE: The beam should be vibrated gently before each reading is taken to ensure that it is properly settled on the knife edges. You may take a picture of the setup for your report./nCalculations: The equation for the deflection at the centre of the beam, for a simply supported beam with a single concentrated central load, is as follows: Given: Where y L I E for Mild Steel Beam: E for Brass Beam: Deflection (m) W - Load (N) Length (m) E-Young's Modulus (N/m²) Second moment of Area [about the Neutral Axis] (m¹) b b (breadth of the beam) d (depth of the beam) Units y = m WL³ 48EI Complete the following table by showing the relevant calculations: m 207GPa 110GPa Cross section of the beam Mild Steel Brass/nGraph: Ploty / Deflection (mm) (Y-axis) vs. W / Load (N) (X-axis) for both beams in a single graph. Discussion: • Is the deflection vs. load graph a straight line? Support your answer by (i) observing the graph and (ii) with the help of the deflection equation. • State three main errors that may have occurred in your assumptions and in the measurements. • Discuss why the brass beam is deflected less compared to the mild steel beam for the same load in this experiment; support this with evidence. Conclusion: • Summarise key points/findings of the experiment • Very briefly explains where this knowledge could be applied Additional note: • No more than 5 pages of report in total should be returned as additional pages will not be marked. This does not include the cover page. • Fonts should not be smaller than size 11. The key for a good report is 5Cs - Clear, Concise, Complete, technically Correct and Critical analysis • Show your calculations to prove that you know how to do them • Make the report looks nice and well-formatted - reuse the tables from the lab sheet but feel free to make adjustments Use diagrams or photos where appropriate (with figure number and description)

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