Aerospace and defense (A&D) manufacturers looking to sustain business efficiency in the face of uncertainty and competition will continue to pursue ever-more advanced design and material solutions to further compress product development cycles, improve system performance, and reduce costs. Rapid adoption of these new, more advanced technologies will be critical for success in the ongoing race for “lighter, stronger, faster, and safer.”

One of the technologies that major A&D manufacturers and smaller specialist companies alike are adopting to support their upward business-growth paths is advanced computational engineering software. The digital toolkits such software provides allow deep interrogation of the complex multiphysics of product performance required to imagine and design anything that flies—from satellites to commercial and military aircraft to drones. Founded in implicit-based algorithms, this software allows calculations to be made, solutions to be optimized, and results to be visualized in seconds rather than hours. Such software goes far beyond the traditional computer-aided design (CAD) tools that many manufacturers still employ today.

Beyond Current CAD Tools

Of course, CAD has been a fundamental contributor to the aerospace industry since its introduction at the dawn of the space race. What is the difference between CAD and today’s more advanced computational engineering software? For starters, there’s the advanced software’s ability to generate all the data necessary for creating a digital twin, which enables a company to design, test, build and then monitor their product’s life digitally, collaboratively and in real-time. The result is a tighter development cycle, informed by feedback from simulation and experimental data, that provides the information needed to shorten lead-times and avoid costly mistakes while significantly improving product quality.

Today’s latest engineering software can be delivered as a highly collaborative platform, with workflows that can template engineering tasks but are also readily customizable to particular projects or customers. The workflows are reusable and shareable, eliminating the need to repeatedly reinvent the wheel. The software also has built-in security and model-format options that allow for data exchange with outside vendors and customers while protecting intellectual property (IP).

An important side benefit of computational engineering software having implicit algorithm-based functionality is that it allows for more seamless integration with advanced manufacturing technologies, most notably additive manufacturing (AM). Also known as 3D printing, AM can produce highly complex shapes that can’t be manufactured any other way. Coupling these two technologies opens the door to countless lightweighting opportunities that didn’t exist even a decade ago and does so without sacrificing—and in many cases improving—performance and structural integrity.

Making the Case for Lightweighting

To fully realize these benefits, computational engineering software quickly and accurately generates the meshes, ribs, lattice structures, and other complex yet topology-optimized shapes that AM makes possible.

The lightweighting benefits from such designs can be substantial. An example of this is the CubeSat (Figure 1), a miniaturized satellite constructed of 1,000 cm 3 modules weighing a maximum of 1.33 kg (3 lb) per unit. Using metal AM, together with advanced topology-optimization software, researchers at the U.S. Air Force Institute of Technology (AFIT) were able to cut the weight of its CubeSat modules in half while increasing overall stiffness by 20% (Figure 2). Perhaps more importantly, the total number of components in each module went from 150 to less than 25, not only reducing the chance of failure six-fold but simplifying the supply chain significantly.

Figure 2. (Left) internal lattice and gyroid design options generated by computational modeling software for lightweighting satellite bus struts and (right) 3D-printed samples of options (printed on a Concept Laser M2).

Performance-Driven Heat Exchanger Design

Heat is another common engineering challenge, a by-product of energy transformation that must be managed for the proper function of many air and space components. Here again, AM’s ability to produce complex surfaces and internal passages that mitigate heating (Figure 3) is a game-changer for manufacturers and design engineers who can employ the advanced topology software that is capable of generating such geometries.

Figure 3. Cross section view of variable thickened shell in a UAV engine cylinder (left), and the completed cylinder (right), all designed with computational engineering software. (Images courtesy nTopology and Cobra Aero)

Cobra Aero, a drone and small-engine design and manufacturing firm in Hillsdale, Michigan, recently applied both lightweighting and temperature-control software capabilities to improve the performance of its A33N drone engine. By replacing the traditional finned-style heat exchanger with a topology-optimized lattice structure, Cobra Aero engineers found they could achieve higher performance at lower engine speeds. This, in turn, allowed them to decrease the size of the drone's cooling duct and reduce vehicle drag, further improving vehicle efficiency. They also found the new design easier to additively manufacture (with a Renishaw 3D printer), with far less post-processing necessary to remove the metal support structures that were required for the previous finned, 3D printed configuration.

Collaboration is King

A similar success story comes from London-based Betatype, which used advanced computational engineering software to optimize a 3D-printed rocket nozzle design (Figure 4). Working closely with the software provider and the metal AM machine maker, the team was able to significantly improve the manufacturability of the titanium component, resulting in a 28% reduction in build time.

Figure 4. Software screenshot of design for rocket nozzle with dual-domain internal cooling channels, and the titanium nozzle as 3D-printed by Betatype. (Screenshot image courtesy nTopology)

This achievement highlights another benefit of the new paradigm in aerospace design and manufacturing: the combination of advanced engineering software, AM hardware, and the people using it forms a nimble, collaborative environment, allowing multiple design iterations to be developed and tested, quickly and cost-effectively.

Future developments

Increasing numbers of AM equipment makers are beginning to align their technology with the latest advanced computational engineering software, allowing manufacturing considerations to be brought to bear on design development from the earliest stages. Design-geometry slice data can now be transferred directly to several leading 3D printer models for manufacturing, without the need for the complex STL files that are widely acknowledged by product designers to be challenging to format into printable data.

Figure 5. Screenshot demonstrates the effects on design of a broad range of multiphysics fields, which are being explored and evaluated through a hypothetical engine cylinder model in nTop Platform. (Image courtesy nTopology)

Aerospace engineers today have access to faster compute speeds that support the latest computational modeling software on a desktop, or the cloud, with ease. They enjoy multi-physics capabilities (Figure 5), implicit and explicit modeling, real-time simulation, and seamless integration with other advanced software tools. Designs can be realized faster without the need to test physical parts until the final iterations.

The continued improvement of near-real-time simulation capabilities that enables aerospace engineers to quickly iterate and optimize their design in a matter of minutes instead of hours or days will further shorten development cycles and enhance innovation.

The aerospace and defense industries have long sought and fought for capabilities in the manufacturing sector that match the imagination of their design engineers. Modern air and spacecraft’s relatively low-volume production and high-performance requirements provide an ideal stage on which to better integrate the latest design and manufacturing capabilities. Advanced computational engineering software and additive manufacturing are now delivering solutions that offer innovation and efficiency together.

This article was written by Ryan O’Hara, Technical Director of Aerospace and Defense, nTopology Inc. (New York, NY). For more information, visit here .

Aerospace & Defense Technology Magazine

This article first appeared in the December, 2020 issue of Aerospace & Defense Technology Magazine.

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