Q4 [Total 4 marks] The 3-dimensional state of strain at a material point in x, y, z coordinates is given by: [ε ] = Exy E yx yy Eyz Ezy =

-120 0-150 00 0 -150 0 240 *10-6 (a) Calculate the volumetric strain and the deviatoric strain invariants [1 mark] (b) Calculate the mean stress and the deviatoric stress tensor [1 mark] (c) Write the characteristic equation of strain [1 mark] (d) Write the characteristic equation of stress [1 mark] The material is linear elastic (E=210GPa, v=0.3).