A specimen and overall experimental methodology were developed to observe the behavior of composite laminates with grooves subjected to out-of-plane contact loading within the groove. The dominant concept of the design is to isolate the response of the specimen around the groove and its loading from other effects. The specimen is designed so that the variability of behavior is negligible across the width of the specimen. Consideration of performance of existing test specimens for other purposes, along with initial efforts within these objectives, led to the final design of a relatively thick composite specimen that is tested with a rigid backface boundary condition. This final specimen configuration has a length of 56 mm, a width of 25 mm, and a maximum groove depth of 3.48 mm. The specimen thickness is nominally 12.5 mm, but is adjusted to allow different laminate configurations to be tested. Initial work showed contact, load transfer, and alignment to be key issues in the design and manifestation of the overall configuration. Finer manufacturing and machining practices, a harder material for the load applicator, and improved testing alignment were therefore introduced to establish the final testing procedure. A quasi-isotropic layup of [-+45/0/90]_(10s) was used for the base testing, with a second layup of [-+30/0]_(13s) used to show the ability to extend the use of the specimen to other stacking sequence configurations. Strain data is captured at either end of the groove and shows the uniform response of the specimen along the groove. Observations on load-displacement data indicate a linear region and a knee load, defined as the deviation from linear behavior. The results show that two modes of failure occur in the grooved composites: a delamination emanating from the bottom of the groove, and cracking under the groove leading to propagation of delamination at an interface away from the groove. In both cases, observations indicate that the damage initiates near the bottom of the groove and then propagates in the longitudinal and/or thickness directions, resulting in the final modes. The test results clearly show that aspecimen and associated test method have been established and verified for the objectives as stated and that this can be used to observe the behavior for various test parameters including laminate configuration. Recommendations are made with regard to extension of the basic testing established herein.
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