An optical interference technique employing Moire patterns has been applied to the determination of swelling geometry in composite adhesive jonts. The test data reveal anisotropic water absorption behavior. One consequence of this anisotropy can be fracture of the miscroscope cover slip used as one adherend and this has enabled a comparison to be made between experimentally and theoretically derived normal displacement fields for mode III fractures in glass.

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This paper discusses the fact that the cured shape of thin unsymmetric laminates do not conform to the predictions of classical lamination theory. Rather than being saddle shaped, as predicted by the classical theory, the paper shows that thin unsymmetric laminates cure into a shape of a right circular cylinder. This anomalous behavior has been observed by many but the paper serves to quantify the effect and to inspire investigators to begin thinking about using the phenomenon to advantage. The paper indicates that the anomalous behavior is repeatable and that thicker laminates conform to the predictions of the classical theory. Laminates of the [0/90 2 / & t h e t a s ; ] T , [0 2 /&thetas; 2 ] T and [0 4 /&thetas; 4 ] T families are investigated for this behavior and it is shown the principal curvature directions of the cylindrical shapes are predictable.

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A previous approximate theory for predicting the room-temperature shapes of unsymmetric laminates is examined in light of the assumptions regarding the inplane strains. The previous theory, which was a geometrically nonlinear extension of classical lamination theory, was felt to be restrictive and this paper develops a new theory in which these restrictions are relaxed. It is shown that despite the previous concern, there is little difference between the previous theory and this theory. This paper presents numerical results for the inplane residual strains of unsymmetric laminates which have cooled from curing into a cylindrical room-temperature shape. It is shown that the residual strains are compressive and practically independent of spatial loca tion on the laminate. In another facet of the paper, the room-temperature shapes of all four-layer unsymmetric cross-ply laminates are predicted. There are only four unique stacking arrangements for this category of laminates and it is shown that their room-temperature shapes are a strong function of their size and their stacking arrangement. Depending on these parameters, the room-temperature shape of a four-layer cross-ply unsymmetric laminate can be a unique saddle shape, a unique cylindrical shape, or a cylindrical shape that can be snapped through to another cylindrical shape.