DRAWING RULES OF MOHR'S CIRCLE:
- Fix the origin (0,0) that is (x,y) at convenient place in the graph.
- X – axis to locate axial stress for both x and y directions.
- Y – axis to locate shear stress for clockwise and anti clockwise shear.
- Tensile stress is positive along x axis right of origin.
- Compressive stress is negative along x axis left of origin.
- Clockwise Shear stress is positive along y axis upward of origin.
- Anti clockwise shear stress is negative along y axis downward of origin..
- When there is no shear force draw Mohr‟s circle from axial stresses. The centre of the Mohr‟s circle bisects axial stresses.
- When there is shear force draw Mohr‟s circle from axial stresses and shear stress. The centre of the Mohr‟s circle bisects the line between
- Angle of inclination is to be drawn from point at centre of Mohr‟s to angle 2θ in clockwise direction.
- Normal stress, and maximum and minimum principal stresses are taken from the origin along the x-axis of the Mohr‟s circle.
- Maximum shear stress is the radius of the Mohr‟s circle, and shear stresses are taken along the y-axis of the Mohr‟s circle.
- The angle between the resultant stress and normal stress in angle of oblique.
In the Mohr’s circle shown below σx and σy are tensile. Shear stress Lemda xy is clockwise to stress plane σx and anticlockwise to plane σy.
Observation from Mohr’s circle:
Given data: σx = OJ is tensile stress on one plane.
σy = OK is tensile stress on other plane. is shear force on the planes.
θ – Angle of inclination. Result from Mohr’sCircle:
CM = radius of Mohr’s circle
λmax It is the maximum shear stress.
QP = σt Shear stress at the point.
ON = σn Normal stress at the point.
OP = σR Resultant stress at the point.
OG = Minimum principal stress
OH = Maximum principal stress.
POG = angle of obliquity.