고체역학 (Gere) — Analysis of Stress and Strain: Problem 7.3-17

7.3-17 The stresses at a point along a beam supporting a sign (see figure) are \(\sigma_x = 15 \text{ MPa}\), \(\sigma_y = 8 \text{ MPa}\), and \(\tau_{xy} = -6 \text{ MPa}\). (a) Find the principal stresses. Show them on a sketch of a properly oriented element. (b) Find the maximum shear stresses and associated normal stresses. Show them on a sketch of a properly oriented element.