Solution to Problem 211 Axial Deformation

Problem 211
A bronze bar is fastened between a steel bar and an aluminum bar as shown in Fig. p-211. Axial loads are applied at the positions indicated. Find the largest value of P that will not exceed an overall deformation of 3.0 mm, or the following stresses: 140 MPa in the steel, 120 MPa in the bronze, and 80 MPa in the aluminum. Assume that the assembly is suitably braced to prevent buckling. Use Est = 200 GPa, Eal = 70 GPa, and Ebr = 83 GPa.
 

Figure P-211

 

Solution to Problem 204 Stress-strain Diagram

Problem 204
The following data were obtained during a tension test of an aluminum alloy. The initial diameter of the test specimen was 0.505 in. and the gage length was 2.0 in.
 

Load (lb) Elongation (in.) Load (lb) Elongation (in.)
0 0 14 000 0.020
2 310 0.00220 14 400 0.025
4 640 0.00440 14 500 0.060
6 950 0.00660 14 600 0.080
9 290 0.00880 14 800 0.100
11 600 0.0110 14 600 0.120
12 600 0.0150 13 600 Fracture

 

Plot the stress-strain diagram and determine the following mechanical properties: (a) proportional limit; (b) modulus of elasticity; (c) yield point; (d) yield strength at 0.2% offset; (e) ultimate strength; and (f) rupture strength.
 

Solution to Problem 203 Stress-strain Diagram

Problem 203
The following data were recorded during the tensile test of a 14-mm-diameter mild steel rod. The gage length was 50 mm.
 

Load (N) Elongation (mm) Load (N) Elongation (mm)
0 0 46 200 1.25
6 310 0.010 52 400 2.50
12 600 0.020 58 500 4.50
18 800 0.030 68 000 7.50
25 100 0.040 59 000 12.5
31 300 0.050 67 800 15.5
37 900 0.060 65 000 20.0
40 100 0.163 65 500 Fracture
41 600 0.433

 

Plot the stress-strain diagram and determine the following mechanical properties: (a) proportional limits; (b) modulus of elasticity; (c) yield point; (d) ultimate strength; and (e) rupture strength.
 

Solution to Problem 142 Pressure Vessel

Problem 142
A pipe carrying steam at 3.5 MPa has an outside diameter of 450 mm and a wall thickness of 10 mm. A gasket is inserted between the flange at one end of the pipe and a flat plate used to cap the end. How many 40-mm-diameter bolts must be used to hold the cap on if the allowable stress in the bolts is 80 MPa, of which 55 MPa is the initial stress? What circumferential stress is developed in the pipe? Why is it necessary to tighten the bolt initially, and what will happen if the steam pressure should cause the stress in the bolts to be twice the value of the initial stress?
 

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