Crank Mechanism

Name Monish Kumar (S11065194) The University of the South Pacific MM313 Dynamic Systems examine 2- testy Mechanism Aim To investigate the relationship between plunger displacement and locomote angle for different ratios between the connecting pole and the tripe. excessively to look at the relationship between the turning moment on the crank shaft and crank angle for a given motor on the piston. Equipment and Instrument Introduction A crank is an artillery wedded at right angles to a rotating shaft by which reciprocating motion is imparted to or received from the shaft. It is used to convert circular motion into reciprocating motion, or vice-versa.The arm may be a bent portion of the shaft, or a separate arm attached to it. Attached to the end of the crank by a pivot is a rod, usually called a connecting rod. The end of the rod attached to the crank moves in a circular motion, while the other(a) end is usually constrained to move in a elongate sliding motion. Theory Figure 1. 0 Slider crank tool The slider crank mechanism as maneuvern in figure 1. 0 is a kinematic mechanism. The piston displacement from the top dead message, x, can be determined from the geometry of the mechanism, in terms of the lengths of the connecting rod, L, and crank, R, and the crank angle, ? can be uttered as x=L+R-(Lcos? -Rcos? ) Also from the geometry, it can be seen that R blunder? =Lsin? And sin? =sin? n Hence cos? =1+sin? n21/2 Where n is a ratio n=LR Procedure element A 1) No tilts and hangers required, the unit initial starting position 0 in the protractor is apparatus and 90? and 270? protractor positions to be in line with the level lines in distributively side. 2) The unit is to be setup in its highest point, Top dead centre point was used to work out the displacement value 3) The mount saucer was turned 30? nd the displacement was noted on the results table, this step was again repeated for different angles and different crank positions. Part B Results PART A remit 1 Results of Piston geological fault cranky angle Displacement P1 (mm) experiment P1 (mm) speculation P2 (mm) experiment P2 (mm) theory P3 (mm) experiment P3 (mm) theory 0 0 0 0 0 0 0 30 3 3. 180748214 5 4. 252344481 7 5. 324742758 45 7 6. 86291501 10 9. 20565874 13 11. 55001055 60 12 11. 51142198 17 15. 51081741 20 19. 51263112 90 22 22. 02041029 31 30. 01960212 39 38. 2202662 one hundred twenty 31 31. 51142198 45 43. 51081741 53 55. 51263112 135 35 35. 14718626 50 48. 80363849 63 62. 4616988 150 38 37. 82176437 53 52. 74976709 68 67. 67857183 180 39 40 56 56 71 72 Table 2 calculation of the angle ? Crank angle ? 0 0 30 5. 73917 45 8. 130102 60 9. 974222 90 11. 53696 120 9. 974222 135 8. 130102 150 5. 73917 180 1. 40E-15 graphical record of Displacement (mm) vs. Crank angle position (? ) Sample Calculation For Displacement P1 at 30? crank angle. To find, ? , n = 5 sin? =sin? n ?=sin-1sin? n=sin-1sin305=5. 73917?To calculate the theoretical displacement, x x=r1-cos? + nr(1-cos? ) x=201-cos30+nr1-cos5. 73917=3. 180748214 mm word of honor 1. After plotting the interpret of Displacement versus the crank angle position, the graph show that the observational values and the theoretical displacement can be compared, the experimental plot and the theoretical plot are almost same. 2. From the results graph the graph show that the measured displacement follows the theoretical curve very well. The maximum difference between the experimental and theoretical displacement is 2 mm. 3. For spacious rotation i. e. 60? the motion of the piston is close to simple harmonic, after 180? the displacement will gradually decrease to 0, it will mould a cosine graph. PART B Piston Balance and Forces Table 3 Piston balance and military capabilitys Angle (? ) No added Piston heaviness P3 (N) 4N Added Piston Weight P3 (N) LHS RHS LHS RHS 0 4. 9 4. 9 4. 9 4. 9 30 5. 3 4. 9 5. 8 4. 9 45 5. 5 4. 9 6. 1 4. 9 60 5. 7 4. 9 6. 3 4. 9 90 5. 8 4. 9 6. 2 4. 9 120 5. 5 4. 9 5. 8 4. 9 135 5. 3 4. 9 5. 6 4. 9 150 5. 1 4. 9 5. 5 4. 9 180 4. 9 4. 9 4. 9 5. 3 225 4. 9 5. 3 4. 6. 5 270 4. 9 5. 4 4. 9 6 315 4. 9 5. 5 4. 9 5. 7 Graph of Weights vs. Angle (No added Piston Weight P3 (N)) Graph of Weights vs. Angle (4N added Piston Weight P3 (N)) Discussion 1) Experimental results was not satisfactory, on that point was some errors made which was due to friction between the mounted disc and the protractor. 2) After looking at the results graph the greatest amount of force approximately at 60? to 90? for no added piston weight. The weight is 5. 8 N at LHS whereas for 4N added piston weight the greatest amount of force is 6. 5 N at 225? RHS. ConclusionThe kinematic motion of the crank mechanism can be expressed in terms of the lengths of the crank and the conrod, and the displacement of the crankshaft. The experimental measurements of piston displacement agree with the prediction of a theoretical model of the piston motion. Due to friction errors were made in the s econd part of the experiment but still manage to fail the results to find out the greatest amount of force being exerted on crank mechanism. Reference Experiment 2 Crank Mechanism. (2013). Suva, Fiji Islands. Kearney, M. (2005, August 15). Kinematics of a Slider- crank mechanism.