The problems for Section 2.9 involve the determination of principal strains and maximum sh...

The problems for Section 2.9 involve the determination of principal strains and maximum shear strain from measurements by strain rosettes.

For the delta strain rosette (Figure 2.20a), let arm a be directed along the positive x axis of axes (x, y).

a. Show that the maximum principal strain is located at angle θ, counterclockwise to the x axis, where

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b. Show that the two principal surface strains ϵ1 and ϵ2 are given by

where

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c. Construct the corresponding Mohr’s circle for the delta rosette.

FIGURE 2.20 Rosette strain gages, Delta rosette, (a) Delta rosette.