1 UNIVERSITI TUNKU ABDUL RAHMAN Faculty :Engineering & ScienceUnit Code:UEME1132 Course:ME, MM, MH, BI, CI, CLUnit Title:Statics Year/ Semester : Y1S1, Y1S2, Y1S3Lecturer :Ms. Lam Foong Sin Session:201405 Experiment 2: Shear Force and Bending Moment Objective:1.Todetermine the bending moment and shear force at any section 2.To establish relationship between bending moment and shear force at any section. Introduction The shear force (F) in a beam at any section, X, is the force transverse to the beam tending cause it to shear across the section. The shear force at any section is taken as positive if the right-hand side tends to slide downwards relative to the left hand portion. The negative force tends to cause the right hand portion to slide upwards relative to the left. Shear force F = Load W but in opposite directions The bending effect at any section X of a concentrated load W is measured by the applied moment Wx, where x is the perpendicular distance of the line of action of W from section X. This moment is called the bending moment M. W F X X W x 2 The bending moment is balanced by an equal and opposite moment exerted by the material of the beam at X, called the moment of resistance. The bending moment is positive if its effect makes the beam to sag at the section considered. If the moment tends to make the beam bend upward or hog at the section, it is negative. For any value of x, the relationship between load W and shearing force F is :- W =dF / dx And the relationship between shearing force and bending moment M is :- F =dM / dx 1.Shear forces apparatus :- 1 set of 80mm x 50mm x 38mm aluminium sectionwith 2 adjustable span support. Apparatus and Materials2.1 unit of shear force dynamometer. 3.2 sets of weight hangers. 4.1 set of weights. 5.2m measuring tape. Shear force and bending moment experiment for concentrated load. Experiments 1.Set up the 2 edge supports on the base of the structural test frame at a distance of 800mm from edge to edge. 2.Place the shear force apparatus on the supports. 3.Horizontally align the beam by adjusting the screws. 4.Place the weight hanger in the centre of the beam (400mm from the support). 5.Adjust the screws to repeat horizontal beam alignment. 6.Zero the shear force and bending moment dynamometers. M =Wx 3 7.Place the weights as given in table below and note the shear force and bending. 8.When placing each weight make sure horizontal beam alignment is carried out and the dynamometers are zeroed. 9.Calculate the percentage error for each set of reading. Weight (g) Force (N) Shear Force experimentShear Force calculation % error Bending moment experiment Bending moment calculation % error Lever arm height =100mm Shear force and bending moment experiment for symmetrical load 10. Set up the 2 edge supports on the base of the structural test frame at a distance of 800mm from the edge to edge. 11. Place the shear force apparatus on the support. 12. Horizontally align the beam by adjusting the screws. 13. Place the weight hangers at a distance of 100mm from the supports. 14. Adjust the screws to repeat horizontal beam alignment. 15. Zero the shear force and bending moment dynamometers. 16. Place the weights as given in the table below and note the shear force and bending moment values. 17. When placing each weight make sure horizontal beam alignment is carried out and the dynamometers are zeroed. 18. Calculate the percentage error for each set of reading. 4 Weight (g) Force (N) Shear Force experimentShear Force calculation % error Bending moment experiment Bending moment calculation % error Lever arm height=100mm Discussion and conclusion Comment on the difference in reading between the experimental value and the calculated value for both shear force and bending moment.