Course detail

Vibrations and Noise

FSI-RVHAcad. year: 2010/2011

Vibrations and noise are a general accompaniment to all machinery operations. The whole chain encompassing the vibration sources, transfer paths of the structure, noise emitters on the machine surface and ambient acoustic environment needs to be analyzed. We need to mainly focus on active methods of reducing vibrations and noise.
Basic areas of examination:
Spectra of vibro-acoustic quantities, experimental analysis,
biomechanics of the human voice and hearing, acoustic properties of closed areas.
Identification of sources of vibrations and noise, aerodynamic sources of noise.
Passive methods of noise reduction.
Active methods of noise reduction - vibroacoustic systems of machines, deterministic models (modelled by means of FEM ) for low-frequency noise), statistic models (solutions of high-frequency noise).

Language of instruction

Czech

Number of ECTS credits

5

Mode of study

Not applicable.

Guarantor

doc. Ing. Vojtěch Mišun, CSc.

Department

Institute of Solid Mechanics, Mechatronics and Biomechanics (ÚMTMB)

Learning outcomes of the course unit

To carry out the machine noise, sourer vibrations and noise identification, the modelling of dynamic phenomenon in the working processes, to realize the active and passive methods of vibrations and noise. By means of the machine noise analysis then to suggest the corresponding constructional and next arrangements, so that the dynamic machine properties would be influenced in desired direction.

Prerequisites

Fundamentals of acoustics:
acoustic wave, acoustic quantities (pressure, intenzity, power), acoustic cavities, acoustic signal spectra, experimental analysis of the acoustic quantities, acoustic fields, spectral and modal properties of acoustic cavities.
Mathematics:
matrix algebra, linear algebra, trigonometrical functions, programming on computers,computer modeling of mechanical structure.

Co-requisites

Not applicable.

Planned learning activities and teaching methods

Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations.

Assesment methods and criteria linked to learning outcomes

The classified accreditation is prescribed for the subject.
The claims for accreditation:
100 % attendance on the exercises. In case of the orderly excused absence is necessary to solve a alternate problem. Accreditation is carried out by means of the written test at the term end. The test consists of the three questions covered a very important areas of the acoustics subject. Participation on the exercises is compulsory. Head of exercises carry out continuous check of student’s presence , their activity and fundamental knowledge. A not excused presence in the exercise is a reason not to give the accreditation. Definite form of the fulfilment of these claims defines the head of exercises in the term begin.

Course curriculum

1. Acoustic variables, linear and decibel representation
2. Spectra of acoustic variables : band pass, tracking,
multispectra
3.Acoustic properties of a closed areas
4.-5. Biomechanics of a human voice and hearing
6.Experimental identification of machine acoustic power
7.Aerodynamic noise sources, principles and examples
8.Passive methods of vibration and noise reduction
9.Principle of reactive dampers of pipe systems
10-11.Deterministic models of vibroacoustic machine systems:
- the coupling structure of vibroacoustic machine systems
- the methods of solution (FEM and BEM)
12-13. Statistical models of vibroacoustic systems (method SEA)

Work placements

Not applicable.

Aims

The target of the subject is theoretical and practical analyses of machine-tools noise, computer modelling their systems for reason to reduce the vibrations and acoustic energy radiation. An identification with the modern methods for analysis and solution of vibration and noise reduction when using the special programme systems for their solution – SYSNOISE, SEADS and etc.

Specification of controlled education, way of implementation and compensation for absences

The inspection of the education is carried out systematically, on the exercises the presence will be written in the student’s list. A student’s preparedness for the education is carried out continuously and individually in the students, or by the short test. In case of orderly excused missing presence it is necessary to fulfil the missing items and optionally to solve some compensatory examples. A missing experimental exercises it is necessary to compensate in the alternate time.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

Nový, R.: Hluk a chvění, České vysoké učení technické, Praha, 2009 (CS)

Recommended reading

Mišun, V.: Vibrace a hluk, Vysoké učení technické, Brno, 1998 (CS)

Classification of course in study plans

  • Programme N3901-2 Master's

    branch M-IMB , 2 year of study, winter semester, compulsory-optional

Type of course unit

 

Lecture

26 hod., optionally

Teacher / Lecturer

doc. Ing. Vojtěch Mišun, CSc.

Syllabus

1. Acoustic variables, linear and decibel representation
2. Spectra of acoustic variables : band pass, tracking,
multispectra
3.Acoustic properties of a closed areas
4.-5. Biomechanics of a human voice and hearing
6.Experimental identification of machine acoustic power
7.Aerodynamic noise sources, principles and examples
8.Passive methods of vibration and noise reduction
9.Principle of reactive dampers of pipe systems
10-11.Deterministic models of vibroacoustic machine systems:
- the coupling structure of vibroacoustic machine systems
- the methods of solution (FEM and BEM)
12-13. Statistical models of vibroacoustic systems (method SEA)

Computer-assisted exercise

13 hod., compulsory

Teacher / Lecturer

doc. Ing. Vojtěch Mišun, CSc.

Syllabus

1. Band pass spectra , different scales, filters
2. Spectral and modal properties of cavities
3. Human voice analysis, its generation, vowel formants
4. Source noise identification, acoustic emitters
5. Acoustic power emitted by the machine
6. Aerodynamic noise sources - blowers, compressors
7. Calculation of the simple reactive noise absorber
8.-9. Deterministic models: solved by FEM
10.-11. Deterministic models: solved by BEM
20.Statistical models, modeling of model subsystems
13.Credit