Question

At a point strains measured with rectangular rosettes are e_A = 600 microns, e_B = 300 microns and e_c = – 200 microns. Determine the principal strains. Find principal stresses also taking E = 2 × 10⁵ and µ = 0.3.

Answer 1

Taking the direction of strain gauge as x-axis, 

e_x = 600 microns 

e_B = e₄₅ = 300 microns and e_c = e₉₀ = – 200 microns = e_y

γ_xy = 200 microns.

∴ Principal strains are

e₁ = 612.3 micron = 612.3 × 10^–6 

e₂ = – 212.3 micron = – 212.3 × 10^–6 

[Note: 1 micron = 1 × 10^–6]