A fiberglass plate and an aluminum plate of similar dimension were coated with PhotoStress plastic and tested in uniaxial tension. The resulting strain patterns that developed around the holes in both plates were similar in geometry, demonstrating a definite correspondence in the gross strain distribution in homogeneous and heterogeneous materials. However, the fringe patterns appeared as smooth unbroken lines for the homogeneous material (aluminum) as shown in Photo A, while for the heterogeneous material (fiberglass), they were discontinuous, with a more-or-less scotch plaid appearance as shown in Photo B. In another example, Photo C shows the strain pattern on a simply loaded fiberglass/honeycomb beam.

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