Plane Stress

Question 1

What is a plane stress distribution?

Answer 1

The stress distribution where the stresses at any point in the solid are contained in a plane

Question 2

Why do we assume the shear stresses must be convergent or divergent when on perpendicular planes?

Answer 2

If they weren’t, then the object would rotate

Question 3

How do we calculate stresses on an inclined direction?

Answer 3

• Firstly, separate the element on the direction you wish to calculate
• Because all objects must be in static equilibrium while modelling, we must balance these forces
• Remember, if provided with stresses,we must first multiply by the area as we cannot sum using stresses

Question 4

If you plot a graph of shear stress against the angle of orientation phi, what comment can you make?

Answer 4

Shear stress is always symmetric relative to the x axis

• x is the angle measured in degrees
• y is the stress on the plane

Question 5

What are complementary stresses?

Answer 5

These are stresses on any two reciprocally perpendicular planes

Question 6

What is a comment we can make about direct stresses in perpendicular directions?

Answer 6

The sum of direct stresses on any two directions reciprocally perpendicular is constant

Question 7

What is a comment we can make about shear stresses perpendicular to each other?

Answer 7

Shear stresses on two directions reciprocally perpendicular are equal in magnitude and opposite in sign