Comsol Case Studies Shake, Rattle, and Roll

	Shake, Rattle, and Roll Comsol

Shake, Rattle, and Roll

Comsol

Technology Category	Analytics & Modeling - Digital Twin / Simulation Analytics & Modeling - Predictive Analytics
Applicable Industries	Buildings Construction & Infrastructure
Applicable Functions	Facility Management Quality Assurance
Use Cases	Building Automation & Control Building Energy Management Predictive Maintenance
Services	Software Design & Engineering Services System Integration
Challenge	Anyone who has slept near an airport will know the sensation — an early morning flight wakes you from sleep, not only because the engine is noisy but also because everything around you seems to be shaking. Likewise, people living near wind turbines, military sites, or hospitals with helicopter landing pads often complain that windows rattle and everyday objects buzz when there is external noise. More puzzling for them is the fact that even when they can discern no sound, they may still notice irritating vibrations. If the response of the sound is 20 vibrations per second (20 Hz) or less, it is described as infrasound, meaning that the original sound is not usually audible to the human ear. The effects, however, are very easy to detect. As waves hit windows, spread to the floor, and affect internal walls, they induce a noticeable indoor vibration. Low-frequency sound waves are notorious for their potential to create annoying disturbances. Noise is part of modern life and there are formal standards that use sound pressure level measurements to recognize high-frequency sound waves at levels of sensitivity, intrusion, and danger for humans. According to Finn Løvholt of the Norwegian Geotechnical Institute (NGI), the generation of building vibration due to infrasound is an area of research that has not been explored extensively. For this reason, NGI, an international center for research and consulting within the geosciences, has been running investigative programs for several years on behalf of the Norwegian Defence Estate Agency. Read More
About Customer	The Norwegian Geotechnical Institute (NGI) is an international center for research and consulting within the geosciences. They have been running investigative programs for several years on behalf of the Norwegian Defence Estate Agency. NGI focuses on understanding and mitigating the effects of low-frequency sound waves, particularly in the context of building vibrations caused by external noise sources such as airports, wind turbines, military sites, and hospitals with helicopter landing pads. Their research aims to alleviate the annoying vibrations that residents experience due to these low-frequency sound waves. NGI employs advanced simulation software and laboratory testing to model and analyze the transmission of sound waves within buildings, enabling them to recommend design adjustments and countermeasures to reduce these disturbances. Read More
Solution	Løvholt and his colleagues decided to create a computer model that would allow them to pick apart the mechanism of low-frequency sound waves hitting and penetrating a building. They used the COMSOL Multiphysics® software to simulate a wooden structure with two rooms separated by a wall, closely mimicking the laboratory experiment setup. Within the model, they assigned a loudspeaker to one room, a microphone to the other, and placed various probes around the structure in order to monitor sound pressure levels and vibrations. Every component was carefully modeled, including the steel frame, the air cavity and studs in the wall, the windows, the plywood sheet, and the plasterboard. The team also had to recognize compound resonances created when two components are joined, such as two pieces of timber that are screwed together. The advantage of COMSOL Multiphysics is that it allows them to enter all the parameters needed to monitor. In particular, it enables them to couple physics, so they can, for example, look at the acoustics of open-air sound interacting with indoor structural dynamics. The coupling works both ways so they can identify feedback. This coupling is crucial for their analysis because sound waves can generate a huge range and variety of resonances. The model really allows them to see these. The NGI team then verified their simulation with laboratory testing of low-frequency sounds as they were transmitted through a wooden construction with two rooms. The motion of the wall and the sound pressure level are the main quantities measured, and results show very close correlation to the COMSOL Multiphysics model. The model shows that the transmission of sound within a building is governed by the way in which low-frequency waves interact with the fundamental modes of the building components, the dimensions of the room, and the way in which air leaks from the building envelope. Vibrations in ceilings and walls seem to be the dominant source of low-frequency indoor sound, with floor vibration driven by sound pressure inside the room. Read More Log in to view content
Contents

Technology Category

Analytics & Modeling - Digital Twin / Simulation

Analytics & Modeling - Predictive Analytics

Applicable Industries

Buildings

Construction & Infrastructure

Applicable Functions

Facility Management

Quality Assurance

Use Cases

Building Automation & Control

Building Energy Management

Predictive Maintenance

Services

Software Design & Engineering Services

System Integration

Challenge

Anyone who has slept near an airport will know the sensation — an early morning flight wakes you from sleep, not only because the engine is noisy but also because everything around you seems to be shaking. Likewise, people living near wind turbines, military sites, or hospitals with helicopter landing pads often complain that windows rattle and everyday objects buzz when there is external noise. More puzzling for them is the fact that even when they can discern no sound, they may still notice irritating vibrations. If the response of the sound is 20 vibrations per second (20 Hz) or less, it is described as infrasound, meaning that the original sound is not usually audible to the human ear. The effects, however, are very easy to detect. As waves hit windows, spread to the floor, and affect internal walls, they induce a noticeable indoor vibration. Low-frequency sound waves are notorious for their potential to create annoying disturbances. Noise is part of modern life and there are formal standards that use sound pressure level measurements to recognize high-frequency sound waves at levels of sensitivity, intrusion, and danger for humans. According to Finn Løvholt of the Norwegian Geotechnical Institute (NGI), the generation of building vibration due to infrasound is an area of research that has not been explored extensively. For this reason, NGI, an international center for research and consulting within the geosciences, has been running investigative programs for several years on behalf of the Norwegian Defence Estate Agency.

About Customer

The Norwegian Geotechnical Institute (NGI) is an international center for research and consulting within the geosciences. They have been running investigative programs for several years on behalf of the Norwegian Defence Estate Agency. NGI focuses on understanding and mitigating the effects of low-frequency sound waves, particularly in the context of building vibrations caused by external noise sources such as airports, wind turbines, military sites, and hospitals with helicopter landing pads. Their research aims to alleviate the annoying vibrations that residents experience due to these low-frequency sound waves. NGI employs advanced simulation software and laboratory testing to model and analyze the transmission of sound waves within buildings, enabling them to recommend design adjustments and countermeasures to reduce these disturbances.

Solution

Løvholt and his colleagues decided to create a computer model that would allow them to pick apart the mechanism of low-frequency sound waves hitting and penetrating a building. They used the COMSOL Multiphysics® software to simulate a wooden structure with two rooms separated by a wall, closely mimicking the laboratory experiment setup. Within the model, they assigned a loudspeaker to one room, a microphone to the other, and placed various probes around the structure in order to monitor sound pressure levels and vibrations. Every component was carefully modeled, including the steel frame, the air cavity and studs in the wall, the windows, the plywood sheet, and the plasterboard. The team also had to recognize compound resonances created when two components are joined, such as two pieces of timber that are screwed together. The advantage of COMSOL Multiphysics is that it allows them to enter all the parameters needed to monitor. In particular, it enables them to couple physics, so they can, for example, look at the acoustics of open-air sound interacting with indoor structural dynamics. The coupling works both ways so they can identify feedback. This coupling is crucial for their analysis because sound waves can generate a huge range and variety of resonances. The model really allows them to see these. The NGI team then verified their simulation with laboratory testing of low-frequency sounds as they were transmitted through a wooden construction with two rooms. The motion of the wall and the sound pressure level are the main quantities measured, and results show very close correlation to the COMSOL Multiphysics model. The model shows that the transmission of sound within a building is governed by the way in which low-frequency waves interact with the fundamental modes of the building components, the dimensions of the room, and the way in which air leaks from the building envelope. Vibrations in ceilings and walls seem to be the dominant source of low-frequency indoor sound, with floor vibration driven by sound pressure inside the room.

Impact #1	The model created using COMSOL Multiphysics allows NGI to make decisions and assign countermeasures to alleviate building vibrations caused by low-frequency sound waves.
Impact #2	The simulation model is much cheaper and quicker than physical testing, enabling more efficient research and development.
Impact #3	The model can be expanded to simulate sound propagation and vibration in an entire building, providing comprehensive insights into building acoustics.

Impact #1

The model created using COMSOL Multiphysics allows NGI to make decisions and assign countermeasures to alleviate building vibrations caused by low-frequency sound waves.

Impact #2

The simulation model is much cheaper and quicker than physical testing, enabling more efficient research and development.

Impact #3

The model can be expanded to simulate sound propagation and vibration in an entire building, providing comprehensive insights into building acoustics.

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Overview

Shake, Rattle, and Roll

Operational Impact