Advances in conventional tape laminates and textile composites provide aircraft manufacturers important technology. In order to overcome the high cost and to improve the damage tolerance of composites, researchers have developed new through-the-thickness reinforcement techniques. The integral structures are more damage tolerant, contain fewer fasteners and are less expensive to manufacture than conventional composite or metallic structures. Woven composites with through the thickness reinforcements such as stitching have good properties not only in mutually orthogonal directions but also in the transverse direction and more balanced properties than traditional tape laminates. They are also expected to have better fatigue and impact resistance due to the interlacing. Because of these potential benefits, these composites are being considered for various applications including primary/secondary components for aerospace structures. The objective of this effort is to develop experimental tools for comparing the performance of these composites reinforced by stitching to unstitched composites. Identification of damage mechanisms and forces available to grow damage is essential for identifying the primary parameters that determine performance. Accurate determination of the driving forces will require extensive manufacturing and experimentation. However, once the reinforcement techniques are well understood, it is anticipated that simplified experiments can be developed that could be used routinely by designers to evaluate the effects of the reinforcements on damage tolerance. This paper specifically addresses the performance evaluation of stitched low cost manufactured composites subjected to static loading. Static tension and compression testing was conducted to determine the Ultimate Tensile and Compressive Strengths, Young's Moduli and Poisson's Ratio. Two different stitch patterns or stitch densities were used for comparison. The first density was five rows of stitching per inch of width, with eight stitches per inch over the entire length. The second density was three rows of stitching per inch of width, with four stitches per inch over the entirelength.
Performance evaluation of unstitched, stitched and z-pinned textile composites under static loading
Leistungsbewertung von ungenähten, genähten und z-pin-verfestigten Textilverbundstoffen unter statischer Belastung
2005
5 Seiten, 10 Bilder, 3 Tabellen, 1 Quelle
Conference paper
English
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