Definition

Graphical method of representing stress or strain about a point. Drawn as a circle in a Cartesian coordinate system, the abscissa of any point on the circle is the normal stress or strain. The ordinate of that point for stress circles is the shear stress. For strain circles it is half the shear strain. The algebraically maximum and minimum abscissas are the principal stress and strains. All angles between stresses and strains are doubled in the graphical representation.