Humans are brilliant creatures who have designed many incredible things over the centuries. But when it comes to perfect design, there’s no competing with nature. That’s why many designers and engineers have looked to nature as an example when it comes to creating new buildings, electronics, airplanes, etc. Christoph Kiener, who investigates new design possibilities for Siemens Corporate Technology, is inspired by the structure of trees.
“A tree’s branch structure contains a transport system that enables an optimized nutrient cycle,” he said. “Things are no different in our lungs, blood vessels or plant roots – fluids are always guided and distributed this way.”
He used these principles to develop a design study for burner tips used in power plants and in energy process technologies, which convert solid or liquid fuels or biomass into fuel gases and incinerate them.
The combination of biomimicry, or biologically inspired design, and additive manufacturing has helped Kiener successfully create parts like a 3D printed metal burner tip that he developed in 2014. The design of the tip made it much easier to cool than the previous design, and so it couldn’t overheat even when its maximum temperature of about 1500ºC was reached. This prompted Kiener to explore the use of additive manufacturing to combine as many features and assemblies in a single component as possible.
Kiener’s first sketch of the design study showed branched cooling ducts. He followed the sketch with computer designs that iterated through optimization processes until a model was ready to be 3D printed. The result was a bucket-sized, fennel-shaped plastic burner tip built in layers with interwoven veins. Kiener believes that biomimicry, generative design and 3D printing could transform industries such as aerospace and automotive.
“At Siemens, we want to make use of these new design possibilities with the help of our product lifecycle management PLM software, because technology developed this way is usually more powerful, cheaper and requires less maintenance,” he said.
Generative design programs are not limited to results based in nature, but the longer the algorithms calculate, the more organic the results tend to be. Nature knows how to achieve maximum results with limited resources, so the parts produced using this technology tend to be strong and require little material and energy. Generative design software perfects characteristics such as flow behavior, strength, heat transmission, and load bearing capacity without the need for any human input, and while these designs are often complex, additive manufacturing can be used to create them quickly and at low cost.
When Kiener created his fennel bulb-shaped burner tip, he and his team fed their first sketches into a Siemens Product Lifecycle Management simulation program.
“We told the program what conditions had to be met, what we wanted to achieve, and in the end, we received an optimized design,” Kiener said.
In this case, what they wanted to achieve was a burner that wouldn’t overheat. Over several days, the PLM program calculated hundreds of arrangements for cooling pipes and the guiding plates distributing burning fuels until it came up with an idea for optimum flow.
“That’s accelerated evolution,” continued Kiener. “Simulations and tests suggest that our design not only serves its purpose, but is also more durable, powerful and affordable than previous models.”
Siemens used this process to develop its 3D printed gas turbine blades, which resemble slightly twisted shark fins. Bionics expert Tobias Kamps is also using the process to integrate several materials into one part – for instance, a component formed by generative algorithms could be formed from expensive high temperature alloys when close to a heat source, and could consist of more common metals where it is farther away from the heat.
“An arm consists of bones, tissue, vasculature and skin,” said Kamps. “With additive manufacturing, we will also be able to produce components from several materials in one single piece.”
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