LDF™ Thermoplastic Composites Technology

Abstract

Recent developments of the innovative LDF™ thermoplastic composites technology are reviewed with emphasis on discussion of the technology's fundamental basis and composites' property performance. The proprietary technology employs reinforce ment of long, aligned discontinuous fibers including carbon, Kevlar® or glass. Fabrication processes such as stretch forming and press forming can be employed in fabrication of LDF™ composite parts. The LDF™ composites technology is cost effective for manu facturing complex-shaped parts of aerospace structures. LDF™ composites show ex cellent mechanical properties comparable to that of the continuous fiber reinforced counterpart, since the reinforcing long fibers with thermoplastic matrix are well aligned. Mechanical test results with various LDF™ composites confirm the fundamental theory for non-continuous fiber reinforcement describing critical fiber length necessary to achieve efficient average stress transfer in a composite. The mechanical and other relevant property data are discussed for performance compar ison of LDF™ AS-4/PEKK or Kevlar®/PEKK composite material systems relative to the matched continuous fiber reinforced composites. Potential application of LDF™ ther moplastic composites technology for high performance aerospace structural parts are discussed with demonstration of thermoplastic wing ribs fabricated for V-22 tiltrotor air craft.