Q2 [Total 5 marks] The state of stress at a point of an elastic solid is given in the x-y- z coordinates by: oxx [0]= 0,₂x 6 s σyy 0x 0₂

6 = oy 6 = = 90 180 0 180 240 0 0 MPa 0 120 (a) Using the matrix transformation law, determine the state of stress at the same point for an element rotated about the x-axis 60° clockwise from its original position [1 mark]; (b) Calculate the stress invariants and write the characteristic equation for the original state of stress [1 mark]; (c) Calculate the deviatoric invariants for the original state of stress [1 mark]; (d) Calculate the principal stresses and the absolute maximum shear stress at the point [1 mark]; (e) What are the stress invariants and the characteristic equation for the transformed state of stress [1 mark].