Hybrid Acoustic Modeling: Bridging Measurements and Simulations in Acoustic Design
Simulation has become an essential tool in modern acoustic design. Engineers in automotive, aerospace, and industrial sectors increasingly rely on acoustic simulations to predict performance, optimize noise treatments, and validate designs. Yet, even the most powerful acoustic CAE tools face practical roadblocks when applied to real-world systems.
Why full acoustic simulations are so challenging
The first challenge lies in the input data. Many components are effectively “black boxes”, suppliers may not disclose the full details due to intellectual property restrictions, and in some cases, they do not even have all the parameters required for an accurate model. Without this foundation, even the most sophisticated simulations start with uncertainty.
Even when data is available, complexity quickly becomes a barrier. Acoustic behavior rarely depends on one factor alone; instead, it emerges from the interplay of vibration, airflow, structural coupling, and non-linear effects. Capturing all of this requires large, multi-physics models that can be difficult to set up and even harder to manage.
Finally, there is the issue of time. In practice, noise problems often appear late in the development cycle, during prototype testing or pre-production phases. At that point, there is rarely time to rebuild or re-run massive simulation models, leaving engineers with few options.
A practical alternative: Hybrid Acoustic Modeling
Hybrid Acoustic Modeling offers a way around these obstacles by combining the strengths of measurements and simulations. Instead of simulating every physical detail from scratch, engineers start with real-world measurements of the acoustic source and use them as the initial input. The simulation then focuses only on how that measured source propagates through the environment.
In practice, this means using high-resolution 3D sound intensity measurements, obtained with Microflown’s particle velocity sensors, as the input to powerful simulation platforms like Hexagon Actran. The result is a workflow that bypasses the most difficult aspects of modeling, while still delivering reliable and predictive results.
Why it works
Hybrid Acoustic Modeling reduces uncertainty by grounding the simulation in real measurement data. Conditions such as load, temperature, and boundary effects are captured directly during the measurement stage, meaning the model begins with reality instead of assumptions. Once the source has been characterized, the propagation stage of the simulation becomes straightforward and efficient. Engineers can then evaluate different scenarios, introduce countermeasures, or study installation effects much faster than with conventional approaches.
This method not only accelerates the workflow but also strengthens confidence in the outcome. Potential treatments such as foams, covers, barriers, or alternative materials can be tested virtually before a single prototype is built. By combining accuracy, speed, and efficiency, Hybrid Acoustic Modeling proves especially valuable when projects are close to deadline and late-stage design changes need to be de-risked quickly.
Case study: Truck rear axle noise optimization
A recent application of this method highlights its value. In collaboration with DAFF, Insuma, and hexagon, using Actran, Microflown Technologies investigated the acoustic output of a truck rear axle during propulsion and braking. By measuring the acoustic sources directly and importing them into a hybrid simulation, the team was able to identify the dominant contributors to noise and propose effective treatments. This led to shorter development cycles and more reliable results compared to relying on simulation alone.
For those interested in the technical details, the full study is available here:
Watch our free webinar
If you would like to see this approach explained in more detail, we also hosted a webinar together with Hexagon Actran where we walk through the workflow, real applications, and lessons learned.
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Conclusion
As noise regulations tighten and product cycles accelerate, engineers are under growing pressure to make faster and more accurate design decisions. Hybrid Acoustic Modeling provides a practical solution by blending the realism of measurements with the predictive power of simulations.
By combining Microflown’s sound intensity measurement technology with Hexagon Actran’s simulation capabilities, engineers gain a robust and efficient workflow for addressing complex acoustic challenges. It is an approach that does not replace simulation, but strengthens it, ensuring that acoustic design is based on both accurate data and reliable prediction.
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