Civil Engineering

A cylindrical 4340 steel bar is subjected to reversed rotating-bending stress cycling, which yielded the test results presented in Figure 8.20. If the maximum applied load is 5000 N, compute the minimum allowable bar diameter to ensure that fatigue failure will not occur. Assume a factor of safety of 2.25 and that the distance between load-bearing points is 55.0 mm. Use the following relation between the stress () and the load (F)   16FL , (d0) is the cylinder  d 03 diameter, and (L) is the distance.

Civil Engineering, Engineering / By

A cylindrical 4340 steel bar is subjected to reversed rotating-bending stress cycling, which yielded the test results presented in Figure 8.20. If the maximum applied load is 5000 N, compute the minimum allowable bar diameter to ensure that fatigue failure will not occur. Assume a factor of safety of 2.25 and that the distance between …

A cylindrical 4340 steel bar is subjected to reversed rotating-bending stress cycling, which yielded the test results presented in Figure 8.20. If the maximum applied load is 5000 N, compute the minimum allowable bar diameter to ensure that fatigue failure will not occur. Assume a factor of safety of 2.25 and that the distance between load-bearing points is 55.0 mm. Use the following relation between the stress () and the load (F)   16FL , (d0) is the cylinder  d 03 diameter, and (L) is the distance. Read More »

Problem 6 (20%). A concrete flood levee with height (H = 6 m) is needed to protect against a high water mark (h = 5 m). 1. Given concrete has density (Pcon. = 2000 kg/mº) and coefficient of friction (Cp = 0.45), determine the minimum thickness b of the levee such that it does not slide. Recall the frictional force is given by the product of the the coefficient of friction and the weight of the object. Assume the width of the levee (i.e., the dimension into the page) is w=1 m. 2. Is this thickness enough to prevent the levee from overturning about its toe? Please clearly illustrate your free-body diagram. ա9=H h=5m toe Figure 3: A conrete flood levee. Assume that water will not seep underneath the levee.

Civil Engineering, Engineering / By

EXPERT ANSWER

We learnt in class that Torricelli measured the atmospheric pressure (Patm = 101 kPa) using a barometer, which he found to be equivalent to the hydrostatic pressure created by 76 cm of Hg (i.e., mercury). This way of recording pressure is still being used today. For example, blood pressure is usually given as the ratio of the maximum (systolic pressure) to the minimum pressure (diastolic pressure). A typical value for this ratio for a human is 120/70, where the pressures are in mm Hg. What would these pressures be in pascals? Please write your answer using the table method.

Civil Engineering, Engineering / By

We learnt in class that Torricelli measured the atmospheric pressure (Patm = 101 kPa) using a barometer, which he found to be equivalent to the hydrostatic pressure created by 76 cm of Hg (i.e., mercury). This way of recording pressure is still being used today. For example, blood pressure is usually given as the ratio …

We learnt in class that Torricelli measured the atmospheric pressure (Patm = 101 kPa) using a barometer, which he found to be equivalent to the hydrostatic pressure created by 76 cm of Hg (i.e., mercury). This way of recording pressure is still being used today. For example, blood pressure is usually given as the ratio of the maximum (systolic pressure) to the minimum pressure (diastolic pressure). A typical value for this ratio for a human is 120/70, where the pressures are in mm Hg. What would these pressures be in pascals? Please write your answer using the table method. Read More »

Problem 5 (15%). An enclosed water tank is fitted with a semi-spherical observation win- dow. The observation window is situated h = 6 m below the water surface, and it is fixed to the side of the tank with four high strength steel bolts. Given that each bolt can sustain a maximum tensile force of 500 kN, is the observation window properly secured? Please clearly illustrate your free-body diagram. side view front view h = 6 m bolt bolt r= 3 m observation window observation window Figure 2: An enclosed water tank is fitted with a semi-spherical observation window.

Civil Engineering, Engineering / By

EXPERT ANSWER

pts); A 3 m wide, 8 m high rectangular gate is located at the end of a rectangular passage that is connected to a large open tank filled with water, as shown in the figure. The water is contained by a hinged gate which is held closed by a horizontal force Fu located at the center of the gate. The maximum possible value for FH is 3,500 kN 4 m 4 m Hinge (a) Starting with the hydrostatic equation for pressure where g =-gey, obtain a formula for the pressure p experienced by the gate as a function of the vertical distance y from the hinge (5 pts).

Civil Engineering, Engineering / By

EXPERT ANSWER

An open tank has a vertical partition and on one side contains gasoline with a density rho = 800 kg/m^3 at a depth of 3.9 m, as shown in Fig. P2.99. A rectangular gate that is 3.9 m high and 2 m wide and hinged at one end is located in the partition. Water is slowly added to the empty side of the tank. At what depth, h, will the gate start to open? Concepts: The pressure in a fluid is a function of the specific weight of the fluid and the height relative to a reference. Pressure is constant on horizontal planes of a continuous mass of fluid. Sum of the moments is zero for equilibrium (a) What is the specific weight of the gasoline? (b) What is the force of the gasoline on vertical gate? (c) Where does the force of the gasoline act with respect to the hinge? (d) What is the moment of the force of the gasoline around the hinge? (a) Y = N/m^3 (b) F = kN (c) h = m (d) M = kN-m Set up the equations for the moment of the water on the gate. (a) What is the moment of the water on the gate? (b) What is the height of the water that yields that moment? (a) M = kN-m (b) h = m

Civil Engineering, Engineering / By

EXPERT ANSWER

Compute the minimum value of plane strain fracture toughness required of a material to satisfy the leak-before-break criterion for a cylindrical pressure vessel similar to that shown in Figure 8.11. The vessel radius and wall thickness values are 250 mm and 10.5 mm, respectively, and the fluid pressure is 4.0 MPa. Assume a value of 3.5 for the factor of safety.

Civil Engineering, Engineering / By

Compute the minimum value of plane strain fracture toughness required of a material to satisfy the leak-before-break criterion for a cylindrical pressure vessel similar to that shown in Figure 8.11. The vessel radius and wall thickness values are 250 mm and 10.5 mm, respectively, and the fluid pressure is 4.0 MPa. Assume a value of …

Compute the minimum value of plane strain fracture toughness required of a material to satisfy the leak-before-break criterion for a cylindrical pressure vessel similar to that shown in Figure 8.11. The vessel radius and wall thickness values are 250 mm and 10.5 mm, respectively, and the fluid pressure is 4.0 MPa. Assume a value of 3.5 for the factor of safety. Read More »