Abstract: Auxetic materials exhibit a unique characteristics when subjected to uniaxial loading. Various structures have been used to model these materials. Among most important auxetic structures, re-entrant structures are of interest in this present study. These structures have different shapes in which are known as lozenge grids, sinusoidal ligaments, square grids, double arrowhead, and structurally hexagonal re-entrant honeycomb could be named. In this paper, finite element approach for the abovementioned structures was employed to obtain basic mechanical properties including Poisson’s ratio and elastic modulus. The study aims at investigating the effect of cross sectional geometry on mechanical properties. For each structure, three different cross sectional geometries were numerically examined. It is evident that mechanical properties of the material could be controlled by changing the geometry of the cross section. The primary outcome of the study is the design guideline on the effect of c

• Publication Date: 19-Apr-2015
• DOI: 10.15224/978-1-63248-045-3-38
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Abstract: The flow characteristics of inline and one slotted cylinder placed in a fin tube heat exchanger model are experimentally investigated using Partical Image Velocimetry (PIV) for Reynolds numbers of 1500 and 4000. In this study, the Reynolds number is calculated based on the cylinder diameter. Qualitative flow visualization was initially employed in order to observe the overall nature of the vortical flow patterns of cylinders. The flow interactions in the streamwise bases of the cylinder with a flat plate surface results in two dimensional vorticity <>, streamline topology <> and velocity vector map behavior.

• Publication Date: 19-Apr-2015
• DOI: 10.15224/978-1-63248-045-3-39
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