E23=20000;//laminate Young’s modulus of 23,given,in N/mm^2
E12=45000;//laminate Young’s modulus of 12,given,in N/mm^2
L12=250;//langth of 12,given,in mm
L23=300;//langth of 23,given,in mm
t12=2;//thickness of 12,given,in mm
t23=1.5;//thickness of 23,given,in mm
Sy=2*10^3;//load