The Genie Meets the Lamp

Additive Manufacturing and Topology Optimization

Nov 14, 2017 · Topology Optimization
Cris Moen, PhD., P.E.

Additive manufacturing by itself is remarkable, like an outrageous wish-granting genie. We believe it’s even better when used with a lesser known technology – topology optimization. This blog post discusses why.

Topology-optimized telescope mirror support geometries. Credit: NBM Technologies.

Why additive manufacturing?

Additive manufacturing (AM) is hot – endorsed as a federal initiative, highlighted by universities, and supported by angel investors. AM is not a fad – its capabilities are powerful and continue to evolve. Everyone in worldwide industries from aerospace to biomedical to building construction is excited by the possibilities that result when you remove manufacturing constraints.

Enter topology optimization

Topology optimization (TO) is the design method perfectly suited to take advantage of the freedom provided by additive manufacturing. This burgeoning tool systematically adds and removes material to computationally create new designs – similar to a virtual compilation of Lego building blocks. But rather than follow a preconceived notion of the design, we let mathematics and physics drive all of the design decisions.

Given a blank slate—a bunch of building blocks for design—what would you do? You would think, calculate, and assemble them the best you could. But your best may not be the best that is technically achievable given the overwhelming, distinct, and unfamiliar solutions TO actually can achieve for the built world. TO attacks each problem with a fresh start, without bias, allowing math to search a design space often so complex it cannot be efficiently navigated by the human mind.

Inside the lamp

Topology optimization is like a lamp for the genie that is AM. The lamp isn’t magic: it shrinks a powerful cloud of possibilities into the best outcomes. It does this by relying principles that govern fundamental definitions of shape and form.

A common goal for TO is finding that material configuration which minimizes mass while satisfying requirements imposed by the system’s demands. The procedure is to set the design domain (the available space for your creation), and then define the loads and demands (mechanical force, thermal, fluid). TO then automatically distributes your building blocks to provide the best response: think lightest beam in an aircraft; smallest axial shortening of a car strut; highest heat dissipation in a heat sink; or minimal pressure drop in a manifold.

TO+AM: A good fit   

With the maturation of AM into a viable commercial process, TO has it made as a method for materializing its most fantastic designs. What a good fit. AM is still generally a batch process. Cost is a factor. TO peers into multiple design dimensions in a methodical, organized fashion. New solutions appear that address multiple goals, such as structural efficiency, multi-functionality, cost, and performance robustness.

Those who value TO value it most for its ability to inspire design. Those who don’t understand it, wonder “How can a computer beat out the creativity and engineering experience of a human being?” A psychological barrier prevails, even in technology champions who already embrace AM. Experts remain few. Commercial software can be limiting; for others, forbiddingly daunting.

When the genie meets the lamp   

At NBM Technologies, we encounter clients that are increasingly hungry for TO+AM. We also experience clients that are open to it, even if it is not what they are sure they need. In these cases, we conduct a pre-screening of their engineering challenge to see if TO+AM is a good match for their problem. Other times, we find ourselves striving to communicate the benefits of this modern design method to clients who have not asked for it. It can sound like simple upselling, but when the genie meets the lamp, the performance improvements are irrefutable.

Count us among the converted. Every engineering problem that comes across our desk becomes a ‘what-if?’; “What if TO has a better solution than what my engineering team would come up through traditional design methods?” Yes – you can print almost everything with AM. But you don’t want to print everything. You want to print the best design possible.

(Header image via Madisontuff.com)