EXAMINATIONS FOR DEGREES AND DIPLOMAS October-November 2008
Mechanics of Solids
First and only paper
Time Allowed: THREE (3) hours
Instructions:
Answer all questions.
-2-
Question 1
Figure 1
Two circular A-36 steel1 rods are connected as shown in Figure 1. The rod CD has a diameter of 30mm. Both members are pin connected together at C (see figure detail). You are asked to determine: a b Identify what kind of structural member are AB and CD respectively. The maximum force P that can be applied to the handle of so the member CD does not fail. The shear force and bending moment diagrams for member AB for this load. The required diameter for the round member AB to resist only the bending action of the force P (use a factor of safety F.S.=2). The diameter of the pin C, also made of A-36 steel, so it acts as a fail-safe mechanism to limit the loading of the member CD to 75% of its critical load (assume the τallow=125 MPa). [20 marks]
c d
e
Continued…
A table providing the material properties of common engineering materials can be found at the end of this exam paper.
1
-3-
Question 2
Figure 2
For the 304 Stainless steel2 beam shown in Figure 2 you are required to: a Calculate the reactions and create the shear force and bending moment diagrams for the beam. Select the lightest weight steel wide-flange beam3 that will safely support the bending load (use a factor of safety, FS=2). Do not include the weight of the beam for this calculation. Derive and graph the equation of, slope and elastic curve by integration. (Ignore the weight of the beam for this calculation.) Determine the magnitude and location of the maximum deflection of the beam. (Ignore the weight of the beam for this calculation.) [20 marks]
b
c
d
Continued…
A table providing the material properties of common engineering materials can be found at the end of this exam paper.
2
A