Aerodynamic Design: Balancing Material Composition with Manufacturing Methods

The precise relationship between material composition and aerodynamic design has evolved rapidly with new tools and new materials. The result is lighter, stronger and more resilient parts that can deliver safer and more fuel-efficient aircraft of all sizes.

“Aerodynamic considerations drive shape and form and material selection follows to meet the associated mechanical demands,” said Dr. Ankit Saharan, director, Metals Technology, Global Additive Minds at EOS.

“You can’t design for aerodynamics in isolation; the geometry must complement the material’s properties and align with the part’s performance requirements,” added Dr. Zaynab Mahbooba, team manager, Metals, R&D at EOS. “Aerodynamic optimization often leads to streamlined geometries that introduce stress concentrations, increasing the localized loading on the material. This raises the demands on material properties like strength, toughness or fatigue resistance.”

Additive manufacturing creates some new material composition properties that aren’t always possible in traditional subtractive solutions. New CAD design tools help design, test and optimize the best design to meet the challenges of lighter and stronger parts. Artificial Intelligence sorts through the nuances of such designs to find the best solution in less time.

Even as aerospace design rapidly evolves, design and materials engineers understand there is no one magic solution. Like the parts themselves, it’s the correct mix of technologies, design expectations and new materials development that push the envelope of aerospace design.

Conrad Smith, director, Aerospace and Defense for Stratasys, said the combination of better design tools and better materials helps shape those better products. “In aerospace, material properties, weight and characteristics, such as flame, smoke and toxicity, are critical,” Smith said. “With our software, GrabCAD Print and PrintPro we have generative tools that make up our accuracy center, which increases the confidence in builds that parts will be right the first time.

“Thanks to this work,” he added, “we also have great warp-adjusted modulation tools, for predictive modeling—no scanning needed for lower quantity runs—as well as refinement, where scanning is used to further refine parts with machine learning during larger production runs.”

Nickel alloy aerospace part — As with this nickel alloy aerospace part, the material properties often define the design and engineering.

Fundamentals of Aerospace Design

Whether defined by traditional materials or new-age alloys, the starting point for aerospace is rooted in basic principles. “The relationship between design and materials in aerospace is deeply interconnected. In many cases, the part is designed around the properties of the material, or conversely, the material is selected and even engineered to meet specific design requirements,” said Mahbooba. “Often, the functional needs of a component define the design space, dictating what materials can be used and how they must perform.

“One of the fundamental goals in aerospace design is weight reduction, which is critical for both performance and fuel efficiency,” she added. “At the same time, components must withstand extreme environments, particularly in the space industry, where a single part might encounter both extremely high and low temperatures during a mission. This requires materials and designs that offer high performance, safety and durability.”

“Aerospace design often begins with the establishment of what are known as design allowables. These are standardized performance metrics for materials under specific conditions, which guide the design of components,” said Saharan. “The MMPDS (Metallic Materials Properties Development and Standardization) provides these allowables, categorized as A- and B-Basis values for conventional manufacturing, and now also C- and D-Basis values for additive manufacturing.

“The next big leap in aerospace design will likely come from advancements in materials. Enabling designers with better and more versatile material choices will unlock new freedoms in how components are conceived and built.”—Ankit Saharan, EOS

“The differences between these bases lie in their statistical confidence,” he added. “A-Basis values represent the highest confidence level, while B-Basis values have a slightly lower statistical threshold. These design allowables help engineers ensure consistency and reliability in material performance.”

The next step is aligning those performance standards with the specific needs of the customer. “When working with end-users, one of the primary questions we get is how our tested material data aligns with their established design allowables,” explained Saharan. “This is particularly important across different aerospace applications—from lightweight structural components to high-performance engine parts. For engine applications, for instance, materials may need to meet stringent requirements such as creep rupture and fatigue strength, particularly with nickel-based alloys.

“End-users are typically evaluating materials like aluminum, titanium and Inconel, and they want to know how the material data we generate—either independently or in collaboration with them—compares to the MMPDS standards,” he added. “Ultimately, in aerospace, the synergy between design and materials is not just important, it’s essential.”

Wing using aluminim — When using materials such as aluminum, used in this wing, end-users want to ensure the materials selected meet the established standards.

Two Viable Solutions

When additive manufacturing first debuted, designers were intrigued by the possibilities to mass-produce small, complicated parts that were difficult or time-consuming for traditional machining. Over time, both additive and subtractive strategies have found a strong, complementary niche. When used in concert, they provide designers with more options and more tools.

Conrad Smith notes that companies such as Stratasys have been able to help a wide range of aerospace companies improve their parts design and manufacturing operation. “Additive manufacturing has a role throughout aerospace, and we continue to demonstrate we can do air- and space-grade parts, from traditional aerospace primes to startups,” Smith said. “The break-even point based on quantities is a relevant discussion point, but key areas where additive easily makes sense, and provides an advantage, is the upfront design, low quantity production and sustainment.

“With additive, you can bring in more machines to help find the sweet spot versus needing personnel to do more traditional manufacturing,” Smith added. “Additive is also great for legacy manufacturing processes where tooling, drawings or expertise may not be available.”

“You can’t design for aerodynamics in isolation; the geometry must complement the material’s properties and align with the part’s performance requirements.”—Zaynab Mahbooba, EOS

“Traditional manufacturing methods, like subtractive machining or casting, are still very relevant—particularly for legacy components or high-volume production where qualification and certification pathways are already well established,” EOS’ Mahbooba noted. “Additive manufacturing is a complementary approach that excels in producing complex, high-performance components, especially where thermal management and weight reduction are critical. It’s well-suited for low part-count applications where the design flexibility enabled by additive manufacturing justifies the added value.”

“Additive manufacturing still represents a small portion of the aerospace value chain,” Saharan said. “While it offers significant advantages, such as reducing part count, consolidating assemblies and enabling more complex geometries, there are still key limitations, particularly in the size of parts that can be produced and the range of applications that are economically viable.”

Heat exchanger — With additive manufacturing, used to build this heat exchanger, one key is to do prototyping for the part and then see whether additive or subtractive manufacturing is the better choice of manufacture of the finished part.

Aerospace Design Solutions Must Conform

In either case, aerospace design must take a holistic approach to all factors—weight, tensile strength and aerodynamic principles. “You can’t design for aerodynamics in isolation; the geometry must complement the material’s properties and align with the part’s performance requirements,” Mahbooba said. “Aerodynamic optimization often leads to streamlined geometries that introduce stress concentrations, increasing the localized loading on the material. This raises the demands on material properties like strength, toughness or fatigue resistance.

“If a part has a sharp corner or a thin trailing edge for aerodynamic reasons, the material must withstand localized stress without failure,” Mahbooba added. “In aerospace applications, properties such as stiffness, fatigue strength, fracture toughness, thermal expansion and creep resistance are critical in determining whether a geometry is viable under real operating conditions.”

Saharan cited an example of a couple of recent EOS projects for Airbus. “We worked on a hydraulic component for the A380 that was manufactured using titanium due to its strength-to-weight ratio and corrosion resistance,” he said. “Another example is the nacelle hinge for the A320, which had specific structural requirements that influenced both material choice and geometry.

“In each case, the design started with load and environmental requirements, and we had to ensure that the materials selected, especially when produced through additive manufacturing, would meet or exceed the necessary design allowables,” Saharan recalled. “The goal was always to align performance data with industry standards like MMPDS while accommodating unique geometric and functional needs.”

AM-designed aerospace part — Additive manufacturers are demonstrating they can design and deliver finished aerospace parts.

Using the New Tools to Create Value

Additive manufacturing once was the hot new technology poised to change the way we manufacture. Then came augmented reality (AR) and virtual reality (VR) to further expand the worker’s skill set. Today, artificial intelligence (AI) is the latest transformative concept sweeping through the plant floor. For the aerospace industry these technologies come with tremendous potential value, but bump up against issues of system reliability and cost-effectiveness.

While AR was the hot thing a couple of years ago, there definitely has been a drop-off in the excitement. “That’s good; that means we’re moving further along. We’ve got to get on that path to realizing value,” said Paul Davies, technical fellow at Boeing during a recent conference at manufacturing hub MxD in Chicago. “It’s not about excitement—it’s about value. We’re making progress.”

That doesn’t mean AI has yet solved all the concerns in aerospace manufacturing. “If we’re using AI to do something, how are we going to accredit that? When will we get to the point where we can actually trust that and not verify with a human?” Davies asked. “The airline industry is heavily regulated. You have FAA on the commercial side. We are required to accredit all of our systems and prove the systems are doing what we think they are doing. In the world of AI, I struggle with how we will get there. I’m sure that we will, but at the moment, that’s a bit of a gap.”

Michael Colasuono, senior manager, Digital and Additive Manufacturing Systems Engineering, Northrup Grumman, told the MxD meeting that data remains a powerful and exacting part of design and manufacturing.

“The biggest challenge for us is, how good is our upstream data? When we talk about the metaverse, AR/VR is just a visualization tool of the work we’ve done before we got to visualization,” Colasuono said. “How well we do our up-front work with our partners and our engineering teams [is important]. It’s not lost on me that we reach into many different places for many different sources of data. How do you verify that data? It’s just one more step to validate that AI model.”

And there remains the human element of manufacturing at a time when technology and data grab so much of the attention. “It’s a balancing art,” Davies said. “If we had this perfect AR system and didn’t have to think about it, that doesn’t lead to satisfying work. That might be good from a company perspective: You swap this person for that person and get the same quality. People don’t want that kind of work. People want to be masters of their craft. So, I struggle with that.”

Prototyping is one area where additive manufacturing has proven particularly effective. “Different components are a better fit for additive,” said Dean Phillips, manager of system integration engineering at MxD. “At MxD, we ask how can we take additive from CAM system, and then how can we take capability and apply that to subtractive manufacturing?

“You need to get the first designs in. We had a lot of prototype tools, and we try to do an 80% solution, see how they fit, and then iterate down from there,” Phillips added. “There’s a lot of great software where you can test before you get to the finished part. Physical testing still is important. There’s a push to find where are the right of levels of redundancy.”

AM-recreated legacy part — Another area where additive manufacturing can be valuable is in the recreation of legacy parts where quality is a more immediate consideration than quantity.

The Next Frontier for Aerospace

There’s little doubt that the potential for technology currently is ahead of its practicality, but that is quickly changing. New materials, faster prototypes and greater use of AI have designers and industry leaders excited about what’s next.

“The next big leap in aerospace design will likely come from advancements in materials,” said Saharan. “Enabling designers with better and more versatile material choices will unlock new freedoms in how components are conceived and built. In a sense, we’re entering a “golden age” of materials innovation—something we haven’t seen at this scale since the 1940s and ’50s, during World War II and the original Space Race.

“As we expand this material palette,” Saharan added, “it will feed directly into application development, allowing engineers to create more efficient, lighter and more capable aerospace systems.”