Straight pull test

In the following sections, we describe the ability to ran tests sensitive to values of Q that are characteristic of processes confined to the interfacial region. First, the sample preparation and experimental procedure are described for two types of tests a straight pull-off test and a cyclic interfacial fatigue test. Then, the results of these tests are presented with data for the forces required for fracture of the samples, as well as the calculations for Q related to the cycHc fatigue test We conclude with a discussion of the significance of the results that have been obtained for our model system. 

Periocular skin is particularly delicate and prone to ectropion. After discussing what ectropion is, 1 discuss the risk factors for its occurrence. These include blepharoplasties and previous resurfacing procedures. 1 perform a simple snap test to determine the elasticity of the lower eyelids in patients who wish to reduce the wrinkling in that area. Lower eyelids which quickly return to the normal position after being pulled down may tolerate straight phenol without forming an ectropion. Patients whose eyelids very slowly return to full apposition should not receive phenolic peels of any kind on the lower lids. Loss of elasticity in the lower lid is common following blepharoplasty and in elderly patients. 

An assumption implicit in most analytical models and pull-out test configurations is that the faces of the crack across which the fibre is bridging are smooth and straight, with single fibres protruding normal to the faces. However, in an actual composite, the situation is much more complex ... 

An interpretation of pull-out tests in terms of interfacial shear bond strength values is only feasible when the fibre geometry is constant and well defined along its length. This is usually the case when using single fibres or an array of parallel fibres, which are straight and circular in cross section. The results of such tests will... 

Figure 3.33 Effect of treatment of the fibre surbce with grease on the characteristic pullout loads in pull-out tests of straight and end hooked steel fibre of 0.45 mm diameter and 25.4 mm length (adapted from Naaman [16]).

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