Adhesion compressive shear delamination

In order to gain some knowledge about the degradation of the adhesive layer during the delamination test, the specimens which successfully passed the test were further tested in compression shear (Fig. 24). For these tests, blocks with a cross section of 50 by 50 mm were cut out of the tested specimens. As a control, specimens of a similar size were cut from the part of the original sample which had not been subjected to the delamination tests. The compression shear tests conhrmed that the five adhesive layers which passed the delamination tests did not suffer any degradation during the harsh treatment. Their shear resistance was hardly reduced after the harsh delamination tests. 

In composites, Drzal and Madhukar (1993) observed that the failure mode depended on the level of fiber/matrix adhesion at low levels, the mechanism was global delamination buckling at intermediate levels, fiber microbuckling at high levels fiber compressive (shear) failure. This is illustrated in Fig. 27. 

In the broad sense, interlaminar adhesion means the adhesion between any laminations of similar or dissimilar materials and hence could be taken to include just about any adhesion test. One particular type for fiber-reinforced plastics, which is known as interlaminar shear strength, is normally considered as a short beam flexural test (sec Chapters 9 and 18). A method peculiar to laminated plastics tube is given in BS 2782, Method 346A [59] and called cohesion between layers of laminated tube. A sample of tube is subjected to compression to induce shear forces between layers and delamination observed by eye,... 

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