Fracture Surface Morphology of Delamination Failure of Polymer Fiber Composites Under Different Failure Modes

The delamination of fiber reinforced polymer composites is one of the most common failures encountered in industrial applications. The most unique macroscopic and microscopic fracture surface features of the delaminations under different failure modes are of interests not only for practical failure analysis investigations but also it helps to reveal the physics behind the delamination phenomenon. In this work, fracture surface morphology of the delaminated carbon fiber polymer composites under mode I, mode II, and mixed-mode I/II loading conditions is investigated mainly with scanning electron microscopy. The unique fractographic features are identified and discussed. The results on ductile and brittle matrix composites have shown their own features, and most important of all the alignment angle of fibrils in the resin-rich ductile matrix could be correlated with the delamination mode

Rapid crack propagation in polyethylene gas pipes

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Comparison of different capacity models for traffic circles

Traffic circles have been used in many countries all over the world. Traffic circles can be defined as intersections where traffic circulates around a center island where priority is given to the vehicles entering from branches and are designed considering weaving movements as the basic goal. There are two most common capacity analysis methods for traffic circles: the method of critical gap acceptance and the method of regression analysis. This study explains the methods of gap acceptance and regression analysis. Ashworth and Field method is investigated and the applicability of these capacity models in Turkey is discussed. The obtained results have shown that both methodologies give satisfactory results; however, the existing methods should be improved (modified) considering conditions

Decline of compound muscle action potentials and statistical MUNEs during Wallerian degeneration

Aim of the study. -In two previous studies, we found that the compound muscle action potential (CMAP) amplitude loss was significantly higher than the loss of estimated motor unit numbers in the course of Wallerian degeneration (WD). In order to overcome some drawbacks of the method previously used, we performed a similar CMAP vs MUNE comparison by using the statistical motor unit number estimation (MUNE) method