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| MECA0062-1 | Vibration testing and experimental modal analysis
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| Duration : | 30h Th, 30h Pr |
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| Number of credits : |
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| Lecturer : | Jean‑Claude Golinval |
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Language(s) of instruction :
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| English language |
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Course contents :
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| Vibration sensors: displacement, speed, acceleration. Signal analysis: power spectral density, discrete Fourier transform, FFT algorithm, digital spectrum analyzers, aliasing and leakage phenomena. Excitation methods in vibration: types of excitation signals (impact, sine sweep, pseudo-random, etc.), electrodynamic exciter, impulse hammer. Theoretical background of modal analysis: transfer function, receptance, mobility, impedance, Bode diagram, Nyquist diagram, development of the dynamic influence coefficient matrix in terms of poles and residues. Identification methods: phase separation and phase resonance methods, identification of modal parameters on the basis of the frequency or impulse response functions, 1 DOF-method(peak picking, circle fitting) and multi-DOF methods, influence of residual terms, multiple excitation. Introduction to model updating methods in linear elastodynamics. Diagnosis of the mechanical state of a machine through vibratory measurements. |
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Learning outcomes of the course :
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| The aim of the course is to train students to use vibration measurement equipment in laboratories, to acquire, process and exploit the vibratory signals as well as modal identification methods, comparison techniques between theoretical and experimental results and parametric correction methods for structural models on the basis of experimental results. |
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Prerequisites and co-requisites/ Recommended optional programme components :
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| This course requires a basic knowledge in mechanical vibrations. |
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Planned learning activities and teaching methods :
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| The lab sessions are organised in groups and upon appointment only.
The first session is led by a member of the staff from the Vibrations and Identification of Structures Laboratory. It is aimed at allowing students to familiarise themselves with the measuring equipment available in the laboratory. During the following sessions, students work independently on a real lattice-work type of structure or an airplane mock-up.
An individual report has to be handed in within a set deadline to be agreed upon with the students. It must include:
1. the detailed description of the measurements made in the laboratory on the test structure,
2. the development and application of two modal parameter identification methods (mode, frequency and damping) of the structure based on the experimental results obtained,
3. the construction and exploitation of a finite element model of the structure tested in the MATLAB environment,
4. the qualitative and quantitative comparison between theoretical and experimental results.
The lab sessions are OBLIGATORY. Any unjustified absence may lead to the refusal of participation in the final exam. |
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Mode of delivery (face-to-face ; distance-learning) :
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| The course includes 30 hours of theoretical lectures and 30 hours of practical work.
It is organised during the first quadrimester. |
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Recommended or required readings :
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| The course notes are handed out during lectures. |
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Assessment methods and criteria :
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| The final grade will be based on the project report and the oral exam:
1. The grade of the project report will be based on the results and the quality of the report (scientific and technical content, conciseness, structuring of the written report and clarity of the text).
2. The oral exam will be based on the individual presentation of the project report. During the oral exam, the students will have to show a solid knowledge of the course materials. A special attention will be devoted to the understanding of the different concepts.
Student assessment criteria:
- Project report: 50%.
- Oral exam: 50%.
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Organizational remarks :
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| The course will start on Friday 23 September 2011 at 9:00 in room 0/528 (B52) |
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Contacts :
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| Jean-Claude Golinval (JC.Golinval@ulg.ac.be)
Mathieu Bertha (Mathieu.Bertha@ulg.ac.be) |
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| Items online : |
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| Copy of the slides |
| Copy of the slides used during the lectures. |
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