Noise and Vibration: Generation, Propagation and Effect on Humans and Environment

General description:

Noise is sound considered unpleasant, loud or disruptive to hearing, which has become an increasing concern throughout the world. While urban noise (from transportation, construction, etc.) brings a negative influence on human health, underwater noise (from pile driving, seismic surveys, etc.) threatens the leaving space of marine mammals and fish. Similar to noise, vibration is undesirable in many cases because it causes damage to engineering structures and discomfort to people. From the viewpoint of physics, noise is vibrations transmitted through a medium, such as air or water. Therefore, effective control of noise and vibration can be possibly be achieved at the source, path, or receiver. In this module, students learn the fundamentals of noise and vibration, including structural vibrations, sound generation and transmission, perception of noise by inhabitants, conduct in-class/lab tests to obtain and analyse vibro-acoustic data, and use numerical tools to mitigate the adverse effects on the urban and marine environment.

Overall structure of the module:

The module structure consists of two interrelated themes; Theory and Project. The Theory theme starts first and students are exposed to fundamentals of noise and vibrations, important sources of noise in air and underwater and dynamics of structures. The coupling between the structure and the surrounding media, in which waves are transmitted, is central in the Theory theme. Vibro-acoustic modelling techniques are discussed and software (that the students use for the Project theme) is introduced. Besides modelling, students are also exposed to measurement setups and equipment regularly used to measure and quantify noise and vibration levels. The theme on Theory is followed by the Project theme in which students apply the theoretical concepts to realistic environmental noise and vibration problems. Case studies, in which levels of vibrations and/or noise are unacceptable, are selected by the instructors together with the relevant industry. Students form groups to tackle the environmental challenging case. Results of this investigation are reported by the group and presented at the end of the quarter.

In the theme theory the mathematical background of acoustics and vibration is taught with an eye on real-life applications. Emphasis is placed on an in-depth analysis of structure-borne noise emission and its effective cancellation either at the source or at the propagation path. This unit is developed such that it includes illustrative applications of the different noise sources in the environment including the effects on people and animals. This unit is fundamental and interlinked to the theme project in which a practical implementation of the theoretical concepts is accomplished.

In the theme Project, students apply the theoretical concepts to realistic environmental noise and vibration problems. The students are divided into groups. Groups are formed by 2-3 students following different MSc programmes in order to enrich the expertise within the groups and to be able to reach scientific depth in the final result of the project.