Strain State at a Single Location
on an Oil Tanker

To better understand the strain state for an old oil tanker, strain gages where attached to the surface of the tanker at the location shown. With the help of the strain gage results, it was determined that the strains at that location were ε_x = -800 μ, ε_y = 400 μ, and γ_xy = 400 μ.

Using Mohr's circle, what is 1) the principal direction and principal normal strains, 2) maximum strain direction and the maximum shearing strain, and 3) the strains at an angle of 30^o?

• Construct the basic Mohr's circle for the given strain state.
• Determine the principal direction from the Mohr's circle diagram, and then the principal strains.
• Find the maximum shear strain direction from the Mohr's circle diagram. Remember that the shear strain is divided by 2 on Mohr's circle.
• Rotate the strain element 15^o using Mohr's circle.