Genesis The history of triaxial fabric can be traced back to the early days of the space program. In the early 1960’s, much research had been done on the best way to return space capsules safely to earth with one of the proposed solutions being the parawing, at that time a recent invention of Francis Rogallo. However, during wind tunnel testing at Langley Air Force Base, the tail section, made of fabric, distorted under particular loading conditions and lost its aerodynamic shape. It was decided not to pursue this technology (Mr. Rogallo continued development and the technology successfully grew into Hang Gliding). Norris Dow, a colleague, was visiting Mr. Rogallo one night and discussed the technical problems. The failure mode was caused by the fabric distorting on the bias (45° angle), a well known problem in textiles. Upon reflection, Mr. Dow realized that if a third yarn direction was woven into the fabric, not at 45°, but at 60°, a fabric construction of equilateral triangles could be created. This construction would be inherently more stable than ordinary fabric as triangles are structurally more stable than rectangles. By close packing the yarns, a “locked intersection” would be created and with the locked intersection geometry the fabric could approach isotropy, e.g. equal strength in all directions.

Structure


The first drawing shows one strand, for instance the horizontal one, being constrained from moving upward by the intersection of the other two strands. Expanding this intersection to two, the second illustration shows the horizontal strand is constrained from moving vertically in either direction. Finally extending the locked intersection configuration to a full unit shows all the strands are constrained from moving in any direction. The locked intersection characteristics and how they affect the performance of triaxial fabric is determined by the size of the yarns and the pitch distance between them. By modifying either of these variables, an amount of extensibility can be designed into the woven fabric, giving a truly engineered fabric structure.

Production

Since this was such an “obvious” solution, Mr. Dow thought one could just go to the local fabric store, buy some “triaxial” fabric, build a parawing and re-run the wind tunnel tests. It took several years of patent research to determine no one, in the thousands of years of weaving fabric, had previously thought of this as a solution to the bias weakness problem in fabrics. Mr. Dow patented the concept in the U.S. and 16 other textile producing countries and in 1965 founded N.F. Doweave, Inc. to commercialize the product. By 1974, 17 Barber-Colman built production machines were operating in a pilot mill in King of Prussia, PA, each producing approximately 500 yards of triaxial material a week. Unfortunately, the textile industry has a high entrance threshold and by 1978 N.F. Doweave had exhausted its funding and had to close.

Current

Barber-Colman acquired the assets of N.F. Doweave and after upgrading the design in certain areas produced 6 additional Triaxial Weaving Machines (TWM). Two of these machines were sold to a Jananese company, one to a British company and three to a domestic company. The three domestic machines were then purchased by an advanced textile and materials processing company and modified one of the machines to create a single end creel system. In the spring of 2010, Triaxial Structures, in conjunction with MTL, Inc., Jessup, PA acquired the 3 domestic machines. Since that time TSI has been working to bring alive the remaining 3 domestic TWMs and is currently operating the first of these.

To examine in-depth the triaxial fabric technology please see our Tech Papers page.