EM203 Mechanics of Materials

Exam #3

Fall 2001

October 30, 2001

Name____________________________________

Section____________________________________

Campus Mail_______________________________

Problem 1 (/30) __________________

Problem 2 (/40) __________________

Problem 3 (/30) __________________

Total __________________

• Please show your work, especially on the last two problems. Partial credit depends on how well you can communicate your solution procedure.
• Tools allowed: 3x5 memory aid card, and a calculator.

1. The welded symmetric “I” section shown has moment of inertia of 4.267 x 10⁶ mm⁴. At this section of the beam, the bending moment about the neutral axis (NA) is 4 x10⁶ N-mm and the shear force is 3 x 10⁴ N. All dimensions shown are in mm.

1. Calculate the normal stress and shear stress at points “a”, “b” and “c”. Show your work. Please place your answers in the following table.

Point	s	t
a
b
c

2. Calculate the average horizontal shear stress on joint “d-e”

2. A state of plane stress is described below. Units for stress are ksi.

-4

		10

a) Sketch Mohr’s circle for the loading

b) Calculate the maximum and minimum normal stresses.

c) Calculate the maximum shear stress.

d) Calculate the normal stress perpendicular to the plane labeled “P.”

e) Calculate the shear stress on plane “P.”

3. The prismatic beam’s loading and shear diagrams are given.

1. Label the force magnitudes on the shear diagram shown
2. Sketch and label the moment diagram below the shear diagram.
3. As engineer on this project, you have time to calculate stresses for only three or four points. State the most likely x and y coordinates for each of the following AND justify each choice with words and or pictures.
1. Location of maximum normal stress due only to bending
2. Location of maximum shear stress due only to transverse load
3. Location of maximum stress due to the combination of bending and shear (in a region that sees both normal and shear stress)