申論題

3. (25分) On the surface of a structural component, the strains are monitored by means of three strain gages arranged as shown in the figure. The following strains were recorded:
εa = 1100 X 10^-6, ε_b =200x10^-6, and ε_c =200x10^-6.
The material properties of the metal alloy are E = 70 GPa, v= 0.33
You MUST draw Mohr's circle (i)(4分) to determine the following quantities and show the results of principal strains (ii)and stresses(iii)on sketches of properly oriented elements (2分each,共4分):

(b) (6分) the principal stains, ε1 =___________ , ε2 =________，andθ_P1=________