JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012 - 30

advancement

Fig. 4: Computational materials and simulation will shorten the cycle: computational materials and manufacturing process simulation offer a tremendous opportunity to speed up the development of composite materials and possibly include the development of materials within the product development cycle

the designer in terms of reduced design space exploration time during design development. As the use of composites is expanded, designers have looked to replace metallic fittings and three-dimensional structures with three-dimensional woven, stitched or braided composites. The challenge of analysis and certification for this type of structure is significant as variability and the behaviour of a materials system in three-dimensional loading become critical. Failure modes such as net tension, bearing, bending, delamination, and inter-laminar shear must be predicted in this structure. So a robust set of analysis tools to support design development and certification is critical to expanding the design space for composite materials and entering the world of three-dimensional composites in a cost-effective manner.

these products. In the last 20 years, computer-aided-design (CAD) has been used to accelerate the design definition process and has been linked to manufacturing through the use of data sets. An example of this is the use of CAD design data sets to define part machining processes. Computational fluid dynamics significantly reduces the need for wind-tunnel testing and leads to a better understanding of complex flows and the impact of design details on performance. Finite element techniques can be used to simulate structural performance in order to speed up structural development and provide a better understanding of the structure’s interaction with the environment. Materials development for airframes has been considered a long-lead time item because development from initial idea to mature properties and manufacturing processes can take 15 to 18 years and many millions of dollars. Because it can take longer to develop a structural material than to develop a new airplane, designers naturally tend to rely on previous-generation materials. The speed of computers and development of software have provided materials and manufacturing engineers with opportunities to speed the development

cycle. Software and computers have provided tools from the quantum level to the vehicle level that allow engineers to simulate the behaviour of materials during fabrication and use. These tools can be used in conjunction with the tremendous laboratory capabilities available today. The computer affords us “a perfect laboratory,” or the ability to perform an experiment over and over again and obtain identical results. It enables engineers to discretely vary specific parameters to understand changes in behaviour and performance. They can compare observations or laboratory experiments at any scale to understand the atomic details of a material during fabrication or while in use. This knowledge can then be used to explore possibilities on the computer and predict behaviours prior to physical development. As a result, material behaviour is understood earlier and development cycles are shortened by focused developmental testing and manufacturing process maturation. There is an incredible opportunity to embrace the use of computational materials and manufacturing process simulation in order to reduce development time and possibly include the development of materials within the product development cycle (see Chart 4). Composite materials have bright future The use of composite materials in aerospace products will continue to grow in the future as composite material systems are optimized for multi-functional performance, expanded into new design spaces with optimization, and used in areas currently dominated by homogeneous materials. Composite materials will be used more frequently as cost is reduced through automation and with advanced knowledge of the fabrication processes’ quality and costs. Composite materials will be injected as a design variable in the product development cycle through the use of a computational tool set for materials and process engineers. n
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Faster development and certification cycles
Finally, there is a critical need for faster material and fabrication process development and certification times. In the aerospace industry, the product development cycle ranges from six to eight years for a high-rate production process. A tremendous set of computer-aided tools have been implemented to facilitate the design and analysis processes that define

30 jec composites magazine / No72 April - May 2012

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JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #72 - April/May 2012