A series of critical, full-scale, physical tests have recently been completed by the NASA Engineering and Safety Center (NESC) at Langley Research Center accurately predicting the Composite Crew Module (CCM)’s successful performance under simulated flight conditions. The CCM is an all-composite alternative for the flight crew module Orion, which is part of NASA’s Constellation program to return man to the Moon and/or Mars.
The NESC is using the CCM project to study material trade-offs between metals and composites in space structures, and the tests’ successful outcome clears the way for increased use of lightweight composites in space vehicles.
HyperSizer, a structural sizing and composite analysis software from Collier Research Corp., was used throughout the almost three-year project to optimize the design, weight, and manufacturability of the CCM, which is constructed of honeycomb sandwich and solid laminate composites. HyperSizer was the first NASA software to be licensed and commercialized as part of the agency’s effort to transfer technology to U.S. business and industry.
“The CCM is an alternative for the metallic crew module, but it has also represented an opportunity for the NASA family to get up the curve on experience with composites,” said CCM Project Manager Mike Kirsch. “Our analytical models predicted the response very well, and now we’re much better informed to make good material trade-offs for future spacecraft.”
HyperSizer works in a feedback loop with FEA to automatically search for solutions that minimize weight and maximize manufacturability. Although able to be used on metallic structures, HyperSizer is particularly applicable to complex composite materials, providing the capability to optimize the architecture of large structures—such as space vehicles, aircraft, railcars, ships, or wind turbine blades—ply-by-ply and element-by-element.
HyperSizer guided design and manufacturing decisions throughout development of the CCM.
“HyperSizer gave us a view into what the physics were doing,” said Kirsch. “We could zoom in on the architecture, refine the design, trade solutions, and evaluate mass and manufacturability very quickly.” The software was also used to display analytical results during five different technical reviews with industry and agency experts.
“I’ve been working with composites for 25 years, and the CCM is the most complicated structure I’ve ever dealt with,” said Jim Jeans, Chief Architect for NASA on the project. “The sizing and strain predictions all held up as the software predicted.”
For load testing, the CCM was blanketed with 280 linear strain gauges—fiber-optic cables generating about 3000 channels of data—and 80 acoustic sensors that listened for fiber breaks in the composite lay-ups. The structure withstood tests of loads applied to the structure to simulate launch abort and parachute deployment.
An internal pressure test required the CCM to withstand twice standard atmosphere pressure of 31 psi to meet the required NASA safety factor of two. Additional testing involving intentional damage of the CCM will continue into early 2010; however, passage of the internal pressure test was essential for keeping the module development program on track.