Faculty of Science, Engineering and TechnologyMEE20004 - STRUCTURAL MECHANICS LAB. 3 - BEAM BENDING - 2015 Sem. 2 By writing my name below, I declare this is an individual assignment and no part of this submission has been copied from any other student's work or from any other source except where due acknowledgment is explicitly made in the text, nor has any part been written for me by another person. Refer to Unit of Study Outline for Plagiarism guidelines. STUDENT NAME & No. : Shehan Fernando (7664613) Lab. Date & Time 12/10/2015 Demonstrator : Dr. Jinghai Lu INTRODUCTION : The aim of this laboratory is to compare experimental and theoretical deflections of a solid steel beam subjected to three point bending. Load is applied using a GUNT bending device. PROCEDURE : 1. Measure the dimensions of test beam cross-section and distance between two roller supports. Calculate the central applied Load required to produce a max. bending normal stress of 190 MPa in the beam. (Note: use Eqs. 1a, 1b and 1c shown on the next page.) Measured Width (mm) *Average Width (b) (mm) 38.10 38.07 38.12 38.09 12.88 Measured Height (mm) 12.64 12.61 *Average Height (h) (mm) 12.71 NOTE : Measure & record b and h at three locations and use Average values in calculations. Distance between the roller supports (L) = 300 mm Calculated Load (P) = 2.598 kN 2. Ensure force and deflection are initially zeroed. Apply the Load calculated in step 1 and record the resulting beam deflection under the indenter. (Note : Is “y” reading +’ve Or –‘ve ?) Actual measured load (P) = 2.608 kN Final measured /experimental deflection (y) = 1.294 (show sign and units) 3. Determine Theoretical value for EI by multiplying the I determined in step 1 with E= 200 GPa. EI THEORY = 1304 (show sign and units) 4. Calculate the theoretical deflection by using Eq. 1(a) - (d) shown overleaf. Theoretical deflection (y) = (show sign and units) Force P y Indenter x x Roller support L/2 1 ofL4 Test beam compare the experimental and theoretical deflections for both central and non-symmetrical loadings.5 line space (200-400 words). Email your individual Lab. 2 of 4 . Discuss errors and possible reasons. L u v 6 EIL Eq.pdf. (2). The Report must include (in order) : (i) This handout as cover sheet /results for your report (1 mark). Unload beam and change the position of one roller support so that the beam is now nonsymmetrically loaded as shown below. (1b) P y 4 x 3 3 L2 x 48 EI Eq. Please see the Study Guide or Blackboard for your demonstrator’s email address. Please scan your report and save whole report as one PDF file with a name of Surname_Initial_Student ID_Lab3. Apply the same calculated load as in Step (1) (which should not exceed 2. (1c) Eq. x (mm) u (mm) v (mm) L (mm) Actual Final measured experimental load (kN) deflection (mm) 200/2=100 200/2=100 300/2=150 100+150=250 2.7 kN) and record final deflection. Please refer to Unit of Study Outline for penalties etc. (1d) 5. Theoretical deflection = (show sign and units) Force P y Indenter x Test beam x Roller support v=150mm u=100mm L For Non-symmetric Load: Pv y x 3 L2 .732 Calculate the theoretical value of deflection by using Eq. (ii) Discussion and Conclusion.v 2 x . (2 marks).For Central Load: b h3 I 12 M MAX. The expected length of the Discussion is between half and one full page using 12 font size with 1.617 0. Report to your demonstrator by due Date – 1 week after conducting Lab. (1a) P L 4 M c I Eq. (2) LABORATORY REPORT: Type and edit your report using Microsoft Word (hand-written is not acceptable except for the sample calculation). max Eq. Overall I believe this was an successful experiment. we did the best by calculating the averages of length and heights to avoid any possible errors. one of them being machine is not working at 100%. it was able to show the purpose of this experiment. Secondly human error could have played a factor too when measuring. perhaps one thing we could have done is to re collaborated the machines before each experiments to gain a result that is closer to the theoretical values (iii) Sample Calculations 3 of 4 . when comparing the theoretical values to experimental values it appeared be different but not significantly. when setting up the machine and taking the final experimental measurements Conclusion . the metal bar. There is not much we can do to make the experiment more controlled. There are multiple factors that could have resulted in an error of the results. the machine has been used for a while and it will have some faults in it.. Discussion After completing the experiment. 4 of 4 .
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