Iterative Design Process for Novel LCAC Composite Shaft

Abstract

KaZaK Composites, a Plasan Company has designed, fabricated, and demonstrated a novel composite S1/S2 lift fan shaft assembly for the Navy’s Landing Craft Air Cushion (LCAC) vehicle. The shaft is a drop-in replacement for the legacy steel shaft assembly and provides the same performance with less than half the weight. A unique integral coupling design allows for angular misalignment and axial deflection while reducing weight, part count, and assembly time over legacy metal flex packs. Use of advanced carbon composite materials greatly reduces corrosion and its associated maintenance costs. The design is readily adaptable and scalable. The focus of this paper is the iterative process of computer based analytical design, prototype manufacture, prototype testing, and failure investigation KaZaK developed to optimize the shaft structure and reduce fabrication costs. The resulting process is a robust, cost-effective method for developing follow-on shaft designs. Utilizing this process, KaZaK’s S1/S2 composite shaft prototype successfully completed an application based, pre-qualification test program that included over-speed testing, static torque proof loading, and fatigue testing in a laboratory environment.