#                  PRINCIPAL STRESSES - 2 D

#This file calculates the two in-plane principal stresses
#from equation (1.11). It also calculates the Von Mises equivalent stress under the assumption of plane stress conditions.
#
#To use this file in cylindrical polar coordinates, uncomment 
#the two lines below and comment the present expressions for 
#s1,s2.
#

#s11:=srr;
#s12:=srt;
#s22:=stt;

s11:=sxx;
s12:=sxy;
s22:=syy;

s1:=(s11+s22)/2+sqrt(((s11-s22)/2)^2+s12^2);
s2:=(s11+s22)/2-sqrt(((s11-s22)/2)^2+s12^2);

sE:=sqrt(s11^2+s22^2-s11*s22+3s12^2);