Cabin noises are a complex topic familiar to anyone who has flown before. Whether it’s the muffled voice of the captain’s announcements, singing partygoers in the back row, or sounds from the galley and lavatory door, they all overlap with the already colorful soundscape of the loud drone of the engines. We asked ZAL acoustic expert Dr. Patrick Cordes how airplane cabins can become quieter. His team is developing a digital simulation tool that identifies weaknesses in acoustic damping even before the cabin is built.

What does the future of cabin acoustics look like?

Cordes: The future of cabin acoustics lies in simulation. Achieving good acoustics during aircraft operation is the result of a long chain of measures, starting from the cabin lining to the customized seat mounts. Noise can enter the cabin through various sound paths. This complexity can increasingly be simulated, reducing the risk of problems being discovered only during flight tests. With improved predictability, we can now identify overlooked sound paths in advance, thereby reducing testing and associated costs.

For individual cabin designs, such as VIP cabins, the situation is even more challenging. Since these cabins are often built only once, extensive acoustic testing for batch size 1 is too elaborate and costly. Therefore, it is important to predict cabin acoustics as accurately as possible. If the cabin is built but acoustically not optimally designed, opportunities for improvement are limited. Additional damping material can sometimes be a solution but also leads to increased weight.

Here, our simulation can help achieve an acoustic bullseye, as demonstrated by a current research project on the predictability of noise-damping measures in VIP cabins (see research project Entirety, ZAL GmbH in collaboration with Lufthansa Technik and Hamburg University of Applied Sciences).

What is the particular challenge?

Cordes: Cabin development never stands still. For example, the use of new, more sustainable materials is currently being researched. 3D printing also enables entirely new lightweight components, which, of course, affects acoustics as well. In short, our simulation models must remain maximally flexible because we don’t even know what innovations are yet to come.

Therefore, our goal is to make our simulation applicable to any cabin setup. We want to precisely determine how noise enters the cabin and which countermeasures help.

Especially in VIP cabins, there are exceptional interior designs and special materials. How can the complexity of the real world be replicated in an acoustic simulation?

Cordes: In simple terms, we start from the small and work our way up to the big. In this process, simulations and experiments go hand in hand. We first examine and simulate material samples, then entire components or structures like a sidewall. Based on these results, a section of the complete aircraft cabin can be simulated. The key is that we always complement this with real tests in the acoustic labs at ZAL. Each component thus exists both “physically” and as a digital twin. This allows us to demonstrate the accuracy of the simulation in the small and fully exploit the flexibility of the simulation tool in the large, without relying solely on experiments. This approach can accompany an entire development cycle and ideally reduce costs and effort, as only a few tests are necessary.

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