Consider a timber beam loaded in 3point bending as shown in

Consider a timber beam loaded in 3-point bending as shown in the sketch. The beam must supports a load P = 30 kN. Given: sigma_all= 26 MPa and Tan = 4 MPa. The cross-section of the beam is to be rectangular with a depth-to-thickness ratio of 4 as shown in the sketch. The gram direction is parallel to the axis of the beam. Plot the following on the same set of axes (This must be a computer generated plot, using Excel, Matlab or some other computer tool. The final product is a single graph with three lines on it, including a legend that clearly distinguishes the three lines. Be sure to label axes appropriately with correct units. Use a range of L values from 0 to lm.): The minimum allowable value of b as a function of the total span length L based on consideration of the bending moment M only. The minimum allowable value of b as a function of the total span length L based on consideration of the shear resultant V only. The minimum allowable value of b as a function of the total span length. Comment on your results.

Solution

The data below is provided for a centrifugal pump with a 72 inch impellor operating at 225 rpm (where e is pump efficiency). What size and speed of a homologous pump should be used to produce 200 cfs at 60ft head when operating at highest efficiency? The answer must be: 51 in and 369 rpm

H (ft) Q (cfs) e (%)

60 200 69

57.5 225 75

55 256 80

52.5 280 83.7

50 303 86

47.5 330 87.3

45 345 88

42.5 362 87.4

40 382 86.3

37.5 396 84.4

35 411 82

32.5 425 79

30 438 75

27.5 449 71

25 459 66.5