Program: Mohr’s Circle
By: Ben Axelrod

This program uses the concept of Mohr’s Circle to calculate the principal planes and the principal stresses at these planes, given the state of stress.   To use, just enter the stress in X direction (SIGMA X), stress in Y direction (SIGMA Y), and the sheering stress (TAU XY).  The program will yield these values:

CEN     => The average stress.  (The X coordinate of the center of the circle.)
R       => The radius of the circle.
MIN     => The minimum stress. (CEN – R)
MAX     => The maximum stress. (CEN + R)
ThetaP1 => The first principal plane.
ThetaP2 => The second principal plane. (ThetaP1 + 90)

NOTE: Remember that Mohr’s Circle is drawn on axes abscissa stress and ordinate sheer stress, both in the principal plane.  Also, ThetaP1 on the object is drawn as 2*ThetaP1 on the circle.  See your strength of materials textbook for more info on Mohr’s Circle.  

Questions, Comments?  Email me at: bmaxelro@syr.edu