Pressurex pressure-indicating sensor films can quickly and accurately identify where and how much force is distributed at the interface of any two contacting surfaces. Dye capsules on the film break under compressive load and quantify the stress characteristics across the surface of the film through color changes. In essence, the film captures pressure information much like taking a snapshot.

In composite layup processes, Pressurex film can measure contact between plies and between core and face sheets. Surface voids can be detected, and pressure inconsistencies indicated that might result in a warped part. In composite manufacturing, Pressurex films can monitor vacuum-bagging pressure, confirm pressure uniformity on filament-wound parts, and measure pressure in mechanically attached joints. Ultra-thin (four to eight millimeters) Pressurex films are sold in sheet and roll form, can be custom cut to size, and are encased in a plastic cover for use around solvents, oils, and other problematic substances.

The company’s Topaq pressure-analysis system digitizes the raw pressure data from the Pressurex film and provides the user with quantifiable information that can be viewed in several formats, including histogram, 2D, or 3D. Sensor Products. Phone: 973-560-4826, web: www.sensorprod.com.

Composites to Help U.S. Air Transport System

Security concerns and dated technologies are just two of the shortcomings to the U.S. air transportation system, as detailed in a new report from the National Research Council (NRC) and Transportation Research Board. “Securing the Future of U.S. Air Transportation: A System in Peril” details the growing demand for air travel (estimated to double in the next 10 to 15 years) and concludes that business as usual in both aircraft construction and air traffic management is not meeting the expansion and improvement necessary to match this estimated growth.

Among the recommended solutions to improve aircraft performance: “The use of new materials, such as modern carbon-based or metal-matrix composites to reduce structural weight fraction.”

Chapter 4, “Improving Aircraft Performance,” lists eight characteristics of composites that merit additional research. Composites are also identified as important for new airframe concepts, such as the blended-wing-body. Within advanced aircraft propulsion technology recommendations, fuel cells are included, many of which use molded and machined graphite bipolar plates in the fuel cell stack.�

For a pre-publication version of the report or to order the final version: The National Acadamies Press, www.nap.edu/catalog/10815.html.

The Eight Characteristics:

• High damage tolerance.
• High stiffness (because many airline structures are sized for stability)
• Active controls (which, if sufficiently reliable, may reduce the need for high stiffness).
• Low cost raw materials and fabrication methods.
• Low density (with high strength-to-weight ratios).
• Means to assure that material properties are satisfactory following repairs and have not degraded unexpectedly over the life of the aircraft in which composites have been incorporated.
• Modularity.
• Resistance to lightning strike (an area where Boeing, for one, is investing millions of dollars).