Mohr s circle is a geometric representation of the 2d transformation of stresses. The transformation equations for plane stress can be represented in graphical form by a plot known as mohrs circle. Mohrs circle equation the circle with that equation is called a mohrs circle, named after the german civil engineer otto mohr. He also developed the graphical technique for drawing the circle in 1882. The idea and procedures are exactly the same as for mohrs circle for plane stress. Mohrs circle for plane stress university of arizona. The circle is centered at the average strain value e avg, and has a radius r equal to the maximum shear strain, as shown in the figure below, related topics the procedure of drawing mohr s circle from a given strain state is discussed in the mohr s circle usage and examples pages. Mohrs circle strains at a point in the body can be illustrated by mohrs circle. Principal stresses and principal strains occur in the same directions. The two principal strains are shown in red, and the maximum shear strain is shown in orange.