MecMovies 4.0 : M13.5: Strain Measurement with Rosettes

scene 8 of 11

ε_a = +800 με

ε_b = -200 με

ε_c = +625 με

The transformation equations for gages b and c have been reduced to:

- 200 με = (800 με) (0.25) + ε_{y} (0.75) + γ_{xy} (0.433)

+ 625 με = (800 με) (0.25) + ε_{y} (0.75) - γ_{xy} (0.433)

For this type of rosette, the γ_xy terms will always be equal in magnitude but opposite in sign. Adding the two equations is an easy way to eliminate γ_xy and obtain one equation in terms of the normal strain ε_y.