고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.144

7.144 Determine the strain \(\epsilon_x\), knowing that the following strains have been determined by use of the rosette shown: \[ \epsilon_1 = +480 \mu, \quad \epsilon_2 = -120 \mu, \quad \epsilon_3 = +80 \mu \] (Referring to Fig. P7.144 for geometric orientation of the strain gages)