The second workshop topic focused on structure and automotive issues and featured presentations by Bill Mullins of the Office of Naval Research, Diane Chong of Boeing, Slade Gardner of Lockheed Martin, and Erik Nyberg of the Pacific Northwest National Laboratory. The speakers gave separate presentations and took questions during and after their individual presentations.
Bill Mullins, Office of Naval Research
Bill Mullins supports the U.S. Navy’s management of the Lightweight and Modern Metals Manufacturing Innovation Institute (LM3I). Mullins works for the Office of Naval Research and explained the Navy’s interest in and research on metals technologies.
Mullins noted that lightweighting of military vehicles has long been a consideration for armies. He said that as early as 1500 BCE, advanced materials were incorporated into horse-drawn chariots and armies and navies have sought to reduce the mass of their vehicles throughout recorded history.
Mullins also explained that the military has turned to the National Research Council (NRC) for help on this subject for a long time as well. He referred to a 1982 NRC National Materials Advisory Board study, Materials for Lightweight Military Combat Vehicles. The study stated that “maximum benefits from the use
of advanced or new materials can be realized only if the overall structural design takes advantage of the properties of the new material. Significant benefits can often be realized through substitution into selected components in a current design. However, for maximum benefits the properties of an advanced material should be incorporated early in the design phase of a new vehicle.”1
The 1982 study identified point solutions that were not really effective for major weight reductions. For example, implementing many of these point solutions could reduce the weight of an M60 tank by a few hundred pounds, which was insignificant compared to the tank’s 60-ton weight. Mullins added that the lesson from the study was that the lightweight materials have to be integrated into the design from the start, not added later. By then it is too late to achieve substantial weight reductions. Mullins then continued to state that, essentially, this also means that improved materials offer little weight reduction to existing vehicle designs.
Mullins also referred to a 1993 report produced by the NRC’s Committee on Materials for the 21st Century. The report Materials Research Agenda for the Automobile and Aircraft Industries included a recommendation that “a systems approach to materials science and engineering should be adopted for enhancing existing materials and developing new materials in a cost-effective, competitive manner. This systems approach should include consideration of the material life cycle of the product and successful paradigms for processing of materials, manufacturing of components, and measuring in-service performance.”2
Mullins also cited a May 2011 report on automotive technology produced by the Center for Automotive Research. That report, Mullins said, indicated that materials substitution has been a traditional method to reduce vehicle weight, but often with unforeseen consequences. For example, the substituted part can have effects on adjacent parts or other performance criteria.3
According to Mullins, a more recent 2012 National Academy of Engineering study noted that lightweight materials development and certification is often isolated from its application. The study indicated that it takes a long time to develop and certify new material for engineering applications, and there is a high risk if the material is used prior to full certifications. Material limitations, however, set most design criteria.4
1 National Research Council, Materials for Lightweight Military Combat Vehicles, National Academy Press, Washington, D.C., 1982, Chapter 4 and Appendix E.
2 National Research Council, Materials Research Agenda for the Automobile and Aircraft Industries, National Academy Press, Washington, D.C., 1993.
3 Center for Automotive Research, Automotive Technology: Greener Products, Changing Skills, Lightweight Materials and Forming Report, May 2011.
4 National Academy of Engineering, Application of Lightweighting Technology to Military Vehicles, Vessels, and Aircraft, National Academies Press, Washington, D.C., 2012.
Mullins also explained the activities of the National Network of Manufacturing Institutes. He said the network focuses on reducing the cost and risk of commercializing new technologies to address relevant manufacturing challenges. Its interest is in production-level scale.
LM3I is headquartered in the Detroit area. It is led by the American Lightweight Materials Manufacturing Innovation Institute (ALMMII), a nonprofit corporation that brings together more than 70 member organizations. The member organizations include manufacturers who use titanium, aluminum, magnesium, and high-strength steels, as well as universities and laboratories that pioneer new applied technology development and research. Mullins explained that LM3I is serving the U.S. manufacturing center in the automotive, aerospace, defense, over-the-road truck, and rail industries.
He said that LM3I’s proposed activities include the following:
- Applied research and demo projects for
- Reducing cost/risk on commercializing new technology;
- Solving precompetitive industrial problems;
- Technology integration—development of innovative methodologies and practices for supply chain integration;
- Small/medium enterprises:
- Engaging with small and medium-sized manufacturing enterprises; and
- Education, technical skills, and workforce development.
According to Mullins, partnerships are essential to LM3I. These include companies of all sizes; state, regional, and local economic development organizations; nonprofits such as professional and industry associations; and educational institutions such as universities, community colleges, and career and technical institutes.
He mentioned that ALMMII focuses on all aspects of the value chain for lightweight materials: rapid development, qualification, optimized use, and commercialization of affordable lightweight structures. He also indicated that ALMMII has a regional economic impact along the I-75 corridor from Detroit, Michigan, south to Knoxville, Tennessee, and that this region has a high concentration of metals producers. He said the ALMMII priority metal classes and alloys include advanced high-strength steels, titanium, aluminum, and magnesium. He noted that the technology development needs have been grouped into six pillars: melt processing; powder processing; thermo-mechanical processing; low-cost, agile tooling; coatings; and joining and assembly.
He said the principles for ALMMII’s portfolio planning are the following:
- Ensure industry buy-in beyond setting priorities:
- All projects can have upfront, company-identified applications;
- A technology transition plan is required—projects shall have industry participation, particularly from original equipment manufacturers and/or suppliers involved in “productionizing” the application;
- Develop criteria for project selection and questions to ask when selecting:
- Project impact—which applications/companies are targeted? How big is the benefit? How many sectors can use it?
- Technology approach—is the status Manufacturing Readiness Level (MRL) 4?
- Portfolio balance—does this project fit into the technology area road-map/theme? Does the execution of the project lead to additional ALMMII capabilities?
- Project team—is the proposal using the best available facilities and people? Are the budgets and timing realistic? What are the cost share considerations?
Dianne Chong, Boeing Company
Dianne Chong of Boeing Company spoke about the joining of dissimilar materials and manufacturing constraints during design. In particular, she discussed Boeing’s recent work on the 787 airliner, which uses a large amount of composite materials and represents a major new development project for the company.
Chong provided an overview of Boeing’s past and current technology and how it has advanced aerospace. Boeing has a broad portfolio of products, from commercial and military aircraft to rockets and spacecraft to electronics. She said that defense products are changing and that customers are increasingly demanding integrated systems. She noted that Boeing does not separate its materials experts into another organization but includes them in all levels of the company’s work.
Chong recounted some earlier aviation history and how materials substitution played a role in the evolution of aircraft. She said the first airplanes were made of wood and fabric, but problems with wood structures led to the introduction of the all-metal airplane, such as the Boeing 247 twin-engine propeller-driven transport. She talked about the Douglas DC-3 entering service in the 1930s and becoming one of the most important transport aircraft ever built. It was used in large numbers during the Second World War, and after the war it formed the backbone of passenger and freight services for many years. The DC-3, Chong explained, was “overdesigned” and considered by many to be virtually indestructible; hundreds of DC-3s remain in service today.
More recently, Boeing introduced the 787 passenger jet, which is the first large commercial aircraft to make extensive use of composite materials for structures, said Chong. Fifty percent (by weight) of a 787 is composites, with 20 percent aluminum, 15 percent titanium, 10 percent steel, and the remainder other materials. The 787 is also made of parts manufactured by numerous partners around the globe, including companies in Australia, Japan, Korea, and Europe.
Chong explained that the use of composites has enabled a number of changes in the cabin to improve the passenger flying experience. These include bigger windows, better air quality, lower cabin altitude, and higher humidity, among others. She said the substantial use of composites has also provided environmental benefits, such as a 20 percent reduction in fuel and CO2 and a 60 percent smaller noise footprint compared to the 767. The aircraft’s NOx emissions are 28 percent below 2008 industry limits, she added.
She noted that although in some ways the 787 represents a substantial technological improvement, it is also part of a historical trend in aviation since the introduction of passenger jets in the 1950s. For example, since the early passenger jets, she said there has been a 90 percent reduction in noise footprint and a 70 percent fuel improvement and reduced CO2.
Chong said that Boeing is continuously seeking to improve quality and productivity. For instance, its 737 production line has experienced a 50 percent reduction in factory cycle time and a 41 percent reduction in covered floor space. Similarly, she noted that the much larger 777 has also had production improvements, such as a 43 percent reduction in factory footprint.
Chong said that Boeing is also trying to reduce its environmental footprint throughout the entire life cycle of its products. This includes reducing manufacturing waste, energy use, and emissions among suppliers and during manufacturing. It also includes improving the emissions, noise, and fuel use of its aircraft as well as resale and materials recovery and recycling of aircraft at end of service. Chong explained that Boeing is pioneering several new technologies, including a fuel cell airplane, sustainable biofuels, and solar power. She mentioned that the company is conducting research on sustainable fuels and seeking to demonstrate alternative, low-carbon life-cycle fuels. She said that Boeing also conducted the first sustainable biofuel demonstration on a commercial airplane and is researching the potential of fuels from plants and algae.
According to Chong, the company is aided by the fact that it has a “trillion dollar backlog” of orders that allows it to make innovations over a long period of time and invest in R&D. She said that the company also tries to look at the horizon and figure out the future of the industry and commercial air travel and then seed technologies that may eventually develop to be incorporated into the company’s products.
Chong acknowledged that corrosion is a major concern for aircraft design and
remains a concern even with new technologies. For instance, the 787 uses many composites that allow the aircraft to operate with higher humidity in the passenger cabin for a more comfortable flight. She said that the designers therefore had to be concerned with where water is condensing and make sure that it is not causing corrosion at those locations.
In response to a question about how materials can help with manufacturing, Chong replied that they may reduce the amount of sealing and joining that is required. This could mean less drilling, filling, and sealing.
Chong was also asked by a participant about how the choice of composites affected capability. She explained that wing structure composites provided improved fuel performance, both because of weight and better flexibility. She said the primary contribution of the composites for the superstructure was weight reduction; however, composites also served to dampen noise. Chong said that they have not only been substitutes, but also led to design nuances in the engine nacelles and wings.
Despite all the work that the company put into predictive tools, Chong said it was still unable to accurately predict what would happen to the composite materials in some circumstances. In addition, there are events that people simply do not think about, such as lightning strikes to the materials. However, Chong explained that building an aircraft using a substantial amount of composite materials was an attractive financial choice and that the 787 still would have been a good airplane—meaning financially successful—if it used substantially less composite.
Some of the participants discussed how similar aeronautics and armored vehicles were to each other. Aviation definitely could provide some technologies and some lessons for lightweighting armored vehicles. One participant asked how airplanes compared to tanks. Chong and other participants noted that airplanes have to be used in the way that they are designed, whereas tanks are often used in different environments and for ways that they are not designed.
Slade Gardner, Lockheed Martin Corporation
Slade Gardner of Lockheed Martin spoke about his company’s work with advanced manufacturing, particularly additive manufacturing (often referred to as “3D printing”). Gardner noted that Lockheed Martin has a broad array of products, from aeronautics to missiles and fire control to space systems, and this creates many diverse demands for manufacturing technologies. He said the company is organized to address critical mission areas including military and civil space, commercial ventures, special programs, strategic and missile defense, and an advanced technology center.
Gardner discussed his recent work with APEX,5 a Lockheed Martin proprietary thermoplastic nanocomposite. APEX is designed for aerospace applications. It has approximately 90 percent of the strength of 6061 aluminum but at about half the density and half the cost. Gardner added that APEX has been used in such applications as an electronics enclosure for a remote processor unit and an airborne network appliance. He also mentioned that when metallized or plated, it can provide electromagnetic interference shielding and grounding equivalent to an aluminum chassis, and that the manufacturing method allows for production rates of more than 3,000 units per day. Gardner then indicated that Lockheed Martin has been experimenting with other uses of APEX, such as manufacturing nosecones and payload fairings for rockets. These are expensive aerodynamically loaded structures, usually made of aluminum, composite, or spruce. Production rates usually are weeks to months for machined or otherwise manufactured articles. As an experiment, Gardner’s company manufactured 40 payload fairings (rocket nosecones) in 2 working days, demonstrating the incredible time savings that is possible by substituting a material.
Gardner also stated that in addition to using APEX in aerospace applications, Lockheed Martin has also sought to apply it to ground systems. One test application was to replace the gunner seat in an 8X8 ground vehicle. It was able to replace a 150-piece steel support structure with a two-piece APEX support structure. This was a drop-in replacement, meaning that it used the same mounting points in the vehicle. Gardner explained that Lockheed Martin managed to achieve an 80 percent recurring cost savings relative to the assembled steel structure it replaced and 75 percent weight savings, or approximately 120 pounds per assembly. The company has identified many candidates in ground vehicles that can be replaced with APEX. These include the front grille, hood, wheel well, fender, dash and combined ducting, among others.
Gardner then turned to the subject of additive manufacturing of large, metallic primary load structures. He said that one method is electron-beam direct manufacturing (EBDM), which is a closed chamber process that builds up a pre-form using additive deposition. This pre-form can then be machined to its final geometry.
He noted that one product that Lockheed Martin has investigated for using this technology is a titanium propellant tank used in the A2100 satellite. Each satellite has five or more tanks, and the forged domes require a 12-month lead time to produce. He said the company spent internal research and development funding to determine whether this technology could manufacture the required tanks. Lockheed Martin determined that a direct-manufactured dome could be made in 3 hours at approximately 50 percent of the cost of a traditionally forged dome. In addition, the baseline forging process limited dome diameter to 49 inches, but the
5 APEX is an acronym for Advanced Polymers Engineered for the eXtreme.
direct-manufactured domes were not limited to 49 inches and could have significantly larger diameters.
Gardner mentioned that Lockheed Martin has also been working on making large structures using EBDM. The company internally funded a manufacturing demonstration of a forward bay cover for the Orion spacecraft that is 7 feet in diameter. The company has identified possible parts that could be manufactured for the F-35 fighter jet. One of the major challenges it faces is inspection of the parts. Lockheed Martin has built test parts with an e-beam system that were heat treated and machined into final shape; these test articles weighed 300 lb and provided an ability to test the directionality effects of how the material was added to the piece. Inspecting and testing these parts does not show any dramatic differences, but minor differences appear in the data when doing statistical analysis of multiple parts. However, these differences are not large enough to alarm the Lockheed Martin engineers. In addition, during testing of the titanium propellant tanks, the Lockheed Martin engineers found no new physics in how the direct-manufactured domes behaved in failure tests as compared to the traditionally manufactured domes. As for inspection, the future will probably bring a combination of traditional inspection and inspection of the articles during the layer-by-layer build process.
Gardner noted that additive manufacturing can also result in the development of tailored alloys. Lockheed Martin can modify the physical properties of the base alloy for hardness, radiation resistance, and transition temperatures. He said that some of the potential applications include ballistic armor, elevated temperature titanium, and internal components for nuclear reactors. He explained that the company is evaluating the possibilities of “super titanium,” which has the density of titanium and the hardness of tool steel.
Finally, Gardner turned to the subject of fused deposition modeling (FDM), which is used for additive manufacturing of polymers and composites. FDM has been used for rapid prototyping equipment, as a rapid prototyping method, for structures such as nose cones and tails for unmanned aerial vehicles, and engine inlets and ducts. He said that the company is seeking to extend the technology with the development of new materials. One of the main benefits, he noted, is how rapidly materials can be tested after they are formulated.
Gardner explained that although many additive techniques use metal in a powder form, “powder scares our people” because of the possibility of stray powder left over after manufacturing. Even a small tiny piece of stray powder, he said, can cause an electrical short if it ends up in the wrong location.
Gardner showed examples of two multi-robot “additive clusters.” These are essentially processing facilities that can include additive manufacturing of polymers and metals with multiple machines located close together. In the multi-robot cluster, robots can also be used for fiber placement and subtractive machining—in other words, one machine adds the material, building up the part, and another
machine then subtracts or machines it to a precise shape and tolerance. He said that the cluster can include non-destructive evaluation and inspection, process monitoring, coatings and treatments, and other processes. Such a cluster could be used for the manufacture of a complex product such as the bus for a satellite.
Eric Nyberg, Pacific Northwest National Laboratory
Eric Nyberg of the Pacific Northwest National Laboratory (PNNL) explained that PNNL had $1.02 billion in R&D funding in 2014. It was founded in 1965 and is operated by Battelle. The laboratory has 4,300 scientists, engineers, and nontechnical staff, and Nyberg stated that it has been the Department of Energy’s top-performing laboratory for 7 years. He mentioned that the laboratory has a number of core capabilities, including chemical and molecular sciences, biological systems science, chemical engineering, and applied materials systems and engineering, among others.
Nyberg noted that applying lightweight metals to defense applications has been common in the United States for nearly a century. For example, he noted that the B-36 bomber, which was first conceived in the closing years of World War II, had 19,000 pounds of magnesium sheet, forgings, and castings, covering 25 percent of its exterior. He said the M-116 amphibious carrier used 60 pounds of magnesium in its floor and that the German Luftwaffe also began using magnesium in its aircraft in the 1930s.6
Currently, the Obama administration has established a goal of reducing greenhouse gas emissions by 40 percent by 2030 and 80 percent by 2050. Nyberg explained that PNNL’s R&D has been motivated by similar objectives since the mid-1990s. This requires substantial vehicle weight reduction for electric vehicles.
Nyberg discussed the possibility of a 30 to 50 percent weight reduction in vehicles. Such weight reduction is unlikely to occur through optimization and trimming in existing designs or through material substitution in existing designs. Instead, it will require material-specific designs. He said it is also unlikely to occur using existing vehicle composition and will require advancements in multi-material technology. Nyberg showed slides indicating various weight reductions in different parts of an automobile as well as a heavy duty vehicle (see Figure 4).
Advanced materials processing is a focus area for PNNL, explained Nyberg. This includes superplastic and hot metal gas forming, metal injection molding, rapid solidification and extrusion, and centrifugal casting. Superplastic and hot
6 S. Mathaudhu and E. Nyberg, “Mg Alloys in Army Applications: Past, Current and Future Solutions,” 2010 Mg Technology, TMS 2010.
metal gas forming can have many applications and benefits. For instance, they can substitute for sheet stamping and can result in part consolidation and reduced cost as well as improved quality and reduced manufacturing costs, among other benefits. Compared to a baseline of steel, these new materials can have substantial impacts. For example, Nyberg posited that aluminum sheet can have a 30 percent mass reduction and magnesium can have an approximately 50 percent mass savings.
Nyberg explained that metal injection molding can have applications in aerospace, defense, transportation, and medical applications as well. The benefits include reduced machining, lower cost, improved quality, and a reduction in scrap.
Nyberg also discussed rapid solidification and extrusion, which has applications in high strength and lightweight alloys, as well as advanced battery and magnet applications. He said the benefits include bulk production capability, minimal scrap, and the ability to produce unique microstructures. He noted that
PNNL is currently developing a new technology that combines friction stir technology and extrusion tools that can produce bulk extrusions that have fine grain microstructures.
Nyberg said that the laboratory had established development targets for its CRADA7 project. These include less than 50 percent current weight, cost less than 90 percent of current door-in-white,8 and greater than 50 percent performance improvement.
Nyberg concluded that future ground and air vehicles will have to integrate armor protection into the construction materials. This will require using modern design and performance tools to address the significant scientific, performance, and economic challenges that have prevented this from happening before.
7 Cooperative research and development agreement, an agreement between a government agency and a private company or university to work together on research and development.
8 Door-in-white is similar to the expression body-in-white (BIW) but for a subcomponent such as a door. BIW refers to the stage in automobile manufacturing in which a car body’s sheet metal components have been welded together but before moving parts, the motor, sub-assemblies, or trim, electronics, etc. have been added and before painting.