August 6, 2009
APL’s Composites Laboratory: An Engineer’s Dream Team
What do these products have in common: a solar-array bracket for a spacecraft, a pod fairing for a submarine hull, a nozzle for a dual-combustion ramjet engine, a Fresnel lens for a world-famous eye institute, and a realistic simulation of a human liver? They’re all models or prototypes produced by APL’s Composites Lab. The facility is home to mechanical, materials, and processing engineers who help translate concepts from 3D graphics into one-of-a-kind models.
For Applied Physics Laboratory staff, the key word in our name is “applied.” Facilities like the Composites Lab, a prototype fabrication area, enable technical staff to try out concepts through hands-on work: If an engineer can imagine it, this lab can probably build it. “Build a little—test a little” through specialized in-house facilities has been a major element in APL work for more than 67 years, and that capability makes us different from most of our peer organizations.
The word composite here means basically two or more materials combined, but retaining their characteristics, to produce a new material. We build parts out of traditional aerospace composites to add strength to materials for a specific purpose. Most composites are reinforced fibers laid out in patterns or cloth covered with some sort of matrix or resin, most commonly an epoxy. The process of making the material and the manufacturing of the part happen simultaneously. Modern fiber-reinforced composites offer very high stiffness and strength with significantly less weight than metals. Typical products include custom electronic and sensor “enclosures.”
Ensuring that the Composites Lab remains on the cutting edge of technology is a continual balancing act for its staff. When deciding whether to go in a particular direction, they must constantly look ahead and anticipate APL’s future needs. APL has been very selective over the years in picking those technologies that make sense to have in house. The idea has always been to be able to test theories by building prototypes, one of a kind or maybe five of a kind, but not mass production. That means that we may not always employ the same processes or the same equipment used in industry (because of cost). Our in-house fabrication capabilities are part of what make APL stand out. Because the application of our technology is unique, the ability to control the processing of advanced composites, polymers, and adhesives is an important asset.
Over nearly 24 years of activity, the role of the Composites Lab has grown from fabrication of an occasional nonstructural part to full responsibility for process development and fabrication of flight-critical spacecraft components. Today, composites are found in virtually all civilian and military aircraft, Department of Defense (DoD) weapon systems, missiles, submarines, and surface ships as well as commercial and military spacecraft. The engineers and technical staff in the lab have helped many APL program and project managers select materials, develop processes, and fabricate parts for a wide range of applications. Staff in this facility also provide technical oversight of primary components fabricated by outside vendors for key Laboratory sponsors.
The staff of the Composites Lab have acquired expertise with nearly every material and process used in the composites industry—from fiberglass with liquid epoxy or vinyl ester resin fairings for submarines and storage housings for compressed natural gas automotive fuel tanks to very thin pitch fiber cyanate ester materials used for lightweight precision spacecraft components.
Composites Lab staff also have expertise in materials other than the typical rigid composite materials. To support a DoD program to improve body armor protection capabilities, Composites staff developed a group of simulated body organs and parts. Because the various internal organs have different properties, they will react to injury in potentially different ways. The goal of the development effort was to provide more realistic test equipment than the standard technique of shooting bullets into clay.
One role of Composites Lab staff is to help their APL “customers” select the right material for the right application. Another role is assisting in troubleshooting or analyzing failure causes. The range of services provided includes actual development and fabrication of a composite structure or bonded assembly for major systems delivered to APL’s sponsors or developing key components or “building blocks” for transitioning fabrication of the full structure to commercial vendors. Composites Lab staff perform a technical oversight role for APL programs or a Navy program office in efforts requiring critical composite structures or bonded assemblies. In addition, the lab performs extensive manufacturing studies for potential large-volume applications.