Question 1
(i) Discuss and define Isotropy, Anisotropy and Orthotropy with regards to engineering materials.
(ii) Regarding Finite Element Analysis:
a. List the three main types of elements and explain how to choose elements?
b. Common sources of errors in FEA?
(iii) After conducting a photoelastic investigation of a sample, you remove the load and notice that a fringe pattern still exists. What could this mean?
Question 2
A shaft has a maximum allowable shear stress of 25 MPa and must carry a torque of 150 N.m. It is required to have a change in diameter from 35 mm to 42 mm. How would you design this section? Show calculations to justify you answer.
Question 3
A delta strain gauge rosette, measured the strain at a point on the surface of a machine element. The measurements are εa = 275 μ, εb = 125 μ and εc = - 75 μ for θa = 90°, θb = 30° and θc = -30°. Use v = 0.333, Calculate:
(a) the in-plane maximum shearing strain,
(b) the true maximum shearing strain.
Question 4
A thin rhomboid shaped plate, situated on the x-y plane, (Figure 1) has side lengths AB = DC = 40 mm and AD = BC = 60 mm and material properties E = 200GPa and v = 0.3. If the change in length of sides AB = 0.04848 mm, AC = 0.1286 mm and AD = 0.00532 mm, what are the stresses relative to the x-y co-ordinate system shown?
