Abstract

The control of noise arising from construction activities effecting the surrounding community is not an issue isolated to a single country.  The fundamental principals of construction noise remain the same the world over, however, the approach to monitoring, controlling and legislating this issue varies between countries and in some cases regional authorities.

In this workshop we have set out to review and summarise the different approaches taken to monitor and control construction noise in the UK, France, Monaco, Germany, Sweden, the USA and Canada.  We have reviewed local legislation and limits, the parameters recorded and best practice with regards to monitoring, reporting and control.

In consultation with experts from each country we have identified the regional factors which have led to the different approaches along with advantages and limitations for each method.

Abstract

Let’s explore how the essence of innovation in acoustics lies in listening carefully and responding to real needs on the ground. By adopting an approach resolutely oriented towards action and practical application, we will demonstrate through case studies and feedback how the most avant-garde acoustic solutions are those designed in perfect harmony with the specific expectations and constraints of users.

This workshop will highlight recent success stories where acoustics has met a variety of challenges :

• Improving industrial maintenance by analysing sound to prevent breakdowns,
• Increasing public safety by accurately identifying critical sound sources such as gunshots,
• Managing a construction site using the “balance approach”.

By focusing on the innovation process, from the recognition of the need to the delivery of an effective and adapted solution, this workshop will illustrate that true innovation is measured not only by its capacity for technological breakthrough, but above all by its tangible and positive impact in the field.

Abstract

Since a few years now, sustainable buildings are in rising demands leading to increasing use of wood construction due to its sustainable character.

Following this trend, mass timber solutions, including cross-laminated timber (CLT), can be an excellent substitute to more traditional, stiffer and heavier building materials such as concrete and steel, when some of their inherent properties aren’t required.

However, while CLT has many advantages as a sustainable building material, it can also pose some rather unique challenges in terms of acoustics. Due to its orthotropic character and low mass density, the material is less effective acoustically, resulting in increased direct sound transmission and flanking transmission paths.

CDM Stravitec has developed and tested floating floor solutions to reduce direct sound transmission. To reduce flanking sound transmission elastic decoupling materials can be installed, and to maintain structural stability, complementary anchors with acoustic decoupling feature need to be installed. Acoustical and structural integrity tests on the developed flanking sound isolation solutions were performed.

CLT panels are also an ideal building material for 3D modular constructions, however, transferring vertical and horizontal forces between stacked modules can compromise acoustic requirements. CDM Stravitec has developed solutions using pre-compressed elastomer decoupling techniques to transfer forces without compromising sound insulation. Structural integrity tests on the couplers and in-situ measurements of airborne sound isolation have shown that good coupling design can achieve the correct load transfer and high sound insulation between the modular structures.

The results of the above-mentioned test campaigns and main findings will be presented and discussed during this workshop, as well as challenges of designing acoustical solutions for mass timber construction without compromising functional and structural integrity of the building.

Keywords: timber construction, cross-laminated timber, modular construction, acoustics, direct sound transmission, flanking transmission, structural integrity.

Abstract

An advanced 2D analysis is developed to accurately determine the Transmission Loss (TL) of axisymmetric dissipative mufflers. These mufflers may include a pod, one or several rings, and/or lining. The model takes into consideration the acoustic properties of perforated sheets and fiber. 

To calculate the eigenvalues and eigenfunctions of sound propagation, the model utilizes complex function analysis, effectively identifying the zeros of the function. Employing the least attenuated mode technique, the model then derives the transmission loss. 

To validate the model’s accuracy, the derived transmission loss is compared with the results obtained from a finite element software. The comparison reveals a remarkable agreement between the two sets of results, affirming the reliability and effectiveness of the developed analysis. 

The proposed model can be easily customized to incorporate mean flow or integrated into a mode matching method 1 to 4 to simulate hybrid silencers with both reactive and dissipative components.

Abstract

This workshop demonstrates the use of Manatee e-NVH CAE collaborative platform by NVH Engineers involved in the development of electric drive systems. In the example chosen to illustrate the workshop, an electric motor with Permanent Magnets is responsible for magnetic excitations of the electric vehicle powertrain, besides the mechanical excitations produced by the gear system. These electromagnetic forces produce dynamic vibrations of the e-powertrain housing and driveline at some specific harmonics, resulting in strong tonalities. This results in so-called electromagnetic Noise, Vibration and Harshness (e-NVH) which can be propagated as air-borne or structure-borne noise.

After troubleshooting the magnetic vibration problem (radial pulsating excitation at H48, exciting a structural mode of the structure), stiffening the housing leads to a significant noise reduction in high-speed range. Besides, eccentric rotor NVH simulations demonstrate that going from 10 to 20% static eccentricity only increases NVH levels of a few dB.

Abstract

This seminar will discuss the latest advancements in noise reduction, with a focus on sound intensity, source localization, and noise ranking methodologies. Participants will learn about innovative techniques and tools for accurately measuring and analyzing sound, which are crucial in solving acoustic problems across various industries. Through a combination of theoretical insights and practical use cases, this session demonstrates how to implement effective noise control strategies. It will cover the usage of particle velocity sensors, the combination of experimental data with numerical simulations, and other state-of-the-art technologies to ensure that acoustic targets are met in diverse environments.

Abstract

Short review of what we are able to do (modelings, measurements, …), what we are working on (2D/3D finite element calculations, indicators, target values, …), the obstacles that remain (poor input data, definition of the appropriate target values, …) with one or two examples on real cases. This would be an introduction to discussion and sharings with participants from other countries on their own practices and feedback. The opportunity to “share knowledges” on this complex topic.