1.8. Principal Planes

Try these first

1. 1.

   Define principal planes.

   Hint

   Think about the types of stress acting on a plane.

2. 2.

   What type of stress is absent on principal planes?

   Hint

   Consider the definition of shear stress.

3. 3.

   What are principal planes?

   • Planes with only shear stress
   • Planes with only normal stress
   • Planes with both types of stress

   Hint

   Think about the definition of principal stresses.

4. 4.

   True or False: Principal planes can have shear stress present.

   • True
   • False

   Hint

   Consider the definition of principal planes.

5. 5.

   A rectangular plate is subjected to a complex state of stress. Calculate the principal stresses and identify the principal planes.

   Hint

   Apply Mohr's Circle to solve for the angles quickly.

6. 6.

   Analyze a beam under bending load to find the points of maximum normal stress. Describe how this relates to principal planes.

   Hint

   Check locations where bending stresses could reach maximum values.