In the traditional design world, engineers design the product, but the material is simply selected from a catalog of available material properties. In the next material world, engineers will design both the product and the materials. Concurrent design will be the key to competing in tomorrow's manufacturing world, researchers say. Traditionally, the performance of materials is quantified in terms of simple sets of properties. Product designers have historically used catalogs of material properties either online or in books and they interface with the material supplier in what is called the material selection process. They simply select materials which meet performance requirements.
In this new world, designers will take advantage of advanced computational simulation tools of materials that have developed over the last decade or two, says Georgia Tech's David McDowell, regents' professor of mechanical engineering and materials science engineering. "With those simulation tools we're opening up the whole design process so that the systems designer of a product has at his or her disposal the capability to tailor the material. It adds the ability to change its structure, deliver more application specific properties and to optimize performance."
The result: greater concurrency of the material development process with the product development process. Normally there is a sequence. Conventionally a material is developed and it sits on shelves until it is selected because its characteristics are deemed to be close enough to what the designer needs for a specific product. The presumption here is that with concurrent design, the completed part will have greater capability if the designer has the capacity to know more about the physical characteristics of the material, adds McDowell.
|In the next material world, engineers will design both the product and the materials, says David McDowell, director, Georgia Tech Mechanical Properties Research Laboratory.|
The presumption is that the material can be designed to meet the required properties and/or performance characteristics. To what extent? It's a young, growing concept, says McDowell. "Today's state-of-the-art modeling and simulation have to be used judiciously to that end. Look at it this way: Modeling and simulation can give you some predictions on material properties and material performance, but they can only be used to support design decisions. The concept is not far enough along to be used in an automated fashion to design new materials."
McDowell estimates that perhaps only about 10% to 20% of the decisions that go into developing and certifying a new material can draw guidance from modeling and simulation. "That means there is still a strong role for empirical or experimental materials development. However, with time we see that fraction of decisions dealing with the development and certification process increasing, based on computer simulation."
He sees the material design concept meeting product concepts such as Boeing's composite airplane, the 787 Dreamliner. "Now when Boeing goes for the next generation beyond the 787, they're envisioning the need to design advanced materials beyond what's already available. That places Boeing in the situation where they will require the capability for relying on modeling and simulation to provide guidance on how to develop those materials."
McDowell says the basic concept is both about knowing more about existing materials as well as contriving to develop new materials. His example is the Steel Research Group at Northwest University led by professor Greg Olson. Organized in the 1980s as a consortium of companies and universities, it explored the use of the new modeling and simulation tools in order to fine-tune the structure of steel. Continuing initiatives have increased both strength and ductility and achieve enhancements that many thought would be impossible to gain. The quantum engineering step helped them determine what they could add to improve strength and fracture resistance. "They were able to enhance the capability of multiple properties which were previously thought to conflict with each other. Instead they found that increasing one would not decrease another."
McDowell says that kind of advance is important because it means we can take already existing materials that have been developed through empirical processing means and intentionally design the structure even at the nanoscale to achieve substantial enhancements. Those would include long-term durability, corrosion resistance, fracture resistance and a lot of other properties that are difficult to get a handle on in empirical development. McDowell says enough is known about how modifications can affect material properties that we can begin to pursue the simulation route in product design.
"While the technology is still at the initial stages, it is not too early to concurrently integrate modeling and simulation with product and materials development." As you prepare to gain cost advantages, be ready for unexpected subtle changes as well, says McDowell. "The aesthetics, the functionality, the shape and the feel of products are all candidates for subtle variation when you jointly design the materials and the product."
A concurrent design strategy can also offer time savings, adds McDowell. His comparison involves those occasions of dramatic shifts in material -- in the concurrent approach versus a similar change with conventional empirically developed materials. "If you can concurrently develop the material with the product design, the JIT type savings can be dramatic." He says DARPA, the U.S. Department of Defense's research agency, documented the possible time savings with its Accelerated Insertion of Materials (AIM) program. One focus was on gas turbine engine companies and how to accelerate the insertion of improved nickel-based super alloys into jet engine applications. It also investigated airframe manufacturers, looking at how to tailor improved materials.