ADVANCED MATERIALS & PROCESSES | MARCH 2025 28 can be produced in, this is not always the case. There may be no other option for testing a braided product than in the off-axis orientation. Additionally, the fiber type and resin system may also impact testing data, especially in the off-axis orientation in which the mechanical properties are tested across the resin system CASE STUDY: BRAIDREINFORCED COMPOSITES As the use of braid in composite parts has increased, so has the testing of braid compared to woven fabrics. This testing has included coupon testing to verify product performance, as well as impact testing[4]. In a 2017 study conducted to compare braid-reinforced composites to woven-reinforced composites, two quasi-isotropic braids with fibers oriented at ±60°/0° and two woven fabrics with fibers oriented at 0°/90° were compared. Quasi-isotropic laminates were created for all four of the material types in this study. During layup of the panels comprising the ±60°/0° quasi-isotropic braided fabrics, all plies were cut and nested in the same 0° direction, while due to the anisotropic nature of the woven fabric, the panels comprising the woven 0°/90° material were comprised of plies cut at a 45° orientation and a 0° orientation. In this study, it was found that quasi- isotropic braid-reinforced laminates showed clear performance benefits compared to the woven fabric quasi- isotropic laminates in both impact and mechanical testing[4]. LOOKING FORWARD Thermoplastic braided materials made of fiber combined with a thermoplastic matrix enable high-rate, lightweight, and predictable performance. Braided sleevings, fabrics, and preforms can be made using commingled thermoplastic yarns or slit-tape thermo- plastics. The slit tapes are made by slitting a unidirectional thermoplastic into narrow widths (3.2 up to 25 mm; 1/8 up to 1 in.) and then winding these tapes onto modified bobbins designed to accommodate this stiffer material. Examples of a fabric made with LEARN MORE The revised ASM Handbook Volume 21, Composites, edited by Nicholas J. Gianaris and John D. Russell will be published in 2026. Digital-first articles from this volume will be released beginning in Spring 2025 in the ASM Digital Library. AM&P is honored to offer an exclusive preview of a selected article from this upcoming publication. thermoplastic materials and a preform made with braided thermoplastic tape are shown in Fig. 7. Thermoplastic slit-tape braided reinforcements provide near-unidirectional (UD) properties and are offered in architectures that best align with the load path of a structure. Braided tape reinforcements offer superior drape compared to UD tapes and semipreg fabrics while maintaining a combination of near-UD properties and high fiber volumes that have reduced part complexity and weight. Like commingled braids, slit-tape braided materials are provided as fabrics, sleevings, and net-shape preforms and are customized to the width or cross-section of a part, minimizing waste. Several braid manufacturers across the U.S. are actively developing braided structures for use in forming a wide variety of composite parts.~AM&P For more information: Alexandra Ivers, process improvement specialist, A&P Technology, 4595 E. Tech Dr., Cincinnati, OH 45245, 513.688.3200, braider.com. References 1. A. Head, New Braid Design Spreadsheet Calculates Fiber Architecture and Aerial Weight Simplifying the Design of Braid Reinforced Composites, Proc. 43rd Int. SAMPE Symposium and Exhibition, p 12691274, 1998. 2. D. Branscomb, D. Beale, and R. Broughton, New Directions in Braiding, J. Eng. Fibers Fabrics, p 11-24, 2013. 3. S.S. Roy and P. Potluri, Braiding: From Cordage to Composites, Textile Research Conference, p 1-4, 2016. 4. M. Braley, B.C. Strohminger, and B. Meyers, A Comparative Evaluation of Quasi-Isotropic Laminates Composed of Either Braided Triaxial Fabric or Woven Fabric, Including Impact and Laminate Performance, SAMPE Conference Proc., Seattle, 2017. Fig. 7 — (a) Braided thermoplastic tape fabric; and (b) preform containing braided thermoplastic tape. Courtesy of A&P Technology. (a) (b)
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