Practical Considerations

Question 2: Practical Considerations on FEA (25 marks) A pulley with 8 bolt holes of a 1-cm diameter, made of a steel, have material properties of E = 207 GPa and v = 0.29, and a mass density p of 7850 kg/m3 as shown below and the right figure shows its axisymmetric cross section with dimensions in cm. The pulley will rotate at a speed of 3,000 + q rpm in its daily working. You are required to conduct a structural static FEA fully using cyclic symmetry to create a small FE model to determine the maximum von Mises stress and max resultant displacement under such a situation. The number of replications about the axis should be determined reasonably.

2.0 + 0.q

Bolt Hole 0.5

Axis of Revolution
(Units: cm)
0.5
b.S
Question 3: FEA on Dynamic Analysis and Vibration (50 marks) Assume the bar has a length of 1 + 0.q m, a modulus of elasticity E of 70 GPa, a mass density p of 2700 kg/m3. It has a square cross-section of (50 + 0.q) x (50 + 0.q) mm as shown in the figure below.

1 + 0.q m 50 + 0.q mm
Determine the first two natural frequencies for the bar a) using a theoretical procedure with 2 two-node bar elements; b) using a Modal Analysis available in ANSYS WB; and c) comparing the results from a) and b) for discussion.