0 mm 210 GPa/m 50000000 GPa/m 0.1 100 GPa/m -y x 0 x y 0 0 ° 0 mm -y x 0 0 mm 1 0 0 0 mm 0 1 0 0 mm 0 0 1 MPa abs(cstr.P) mm MPa s.xx*x^2/(x^2+y^2) + 2*s.xy*y*x/(x^2+y^2) + s.yy*y^2/(x^2+y^2)