고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.138

7.136 through 7.139 The following state of strain has been measured on the surface of a thin plate. Knowing that the surface of the plate is unstressed, determine (a) the direction and magnitude of the principal strains, (b) the maximum in-plane shearing strain, (c) the maximum shearing strain. (Use \(\nu = \frac{1}{3}\).) 7.138 \(\epsilon_x = +160 \mu\), \(\epsilon_y = -480 \mu\), \(\gamma_{xy} = -600 \mu\)