MECA0062-1

Duration

26h Th, 26h Pr, 30h Proj.

Number of credits

	Master MSc. in Aerospace Engineering, professional focus in aerospace engineering	5 crédits
	Master Msc. in Mechanical engineering, professional focus in mechatronics	5 crédits
	Master MSc. in Mechanical Engineering, professional focus in sustainable automotive engineering	5 crédits

Lecturer

Loïc Salles

Language(s) of instruction

English language

Organisation and examination

Teaching in the first semester, review in January

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit contents

This course provides a comprehensive introduction to experimental modal analysis, a key technique in structural dynamics and mechanical vibration analysis. It focuses on understanding the dynamic properties of structures and systems through experimental testing and data analysis. Topics include vibration theory, instrumentation, data acquisition, signal processing, modal parameter extraction, and validation of modal models. Practical applications in mechanical, aerospace, civil engineering, and other fields will be emphasized.

Course Structure :

Introduction to Modal Analysis: Overview, Applications, and History
Fundamentals of Vibrations and Theoretical Modal Analysis: Single and Multi-degree-of-Freedom Systems, Natural Frequencies, Damping
Instrumentation for Modal Testing: Sensors, Exciters, Data Acquisition Systems, Calibration Techniques
Data Acquisition and Signal Processing: power spectral density, discrete Fourier transform, FFT algorithm, digital spectrum analyzers, aliasing and leakage phenomena.
Modal Parameter Extraction Methods: Curve Fitting, Peak Picking, Complex Mode Indicator Function (CMIF)
Advanced Modal Parameter Extraction: PolyMAX, Stochastic Subspace Identification (SSI)
Experimental Modal Analysis Procedures: Test Planning, Setup, Measurement Techniques, Data Validation
Modal Model Validation and Correlation: Modal Assurance Criteria (MAC), Orthogonality Checks
Use of modal parameters
Finite Element Model Updating Using Experimental Data: Theory and Practical Approaches
Operational Modal Analysis: Ambient Vibration Testing, Output-Only Techniques, Applications
Hands-On Modal Testing: conducting experiments on an aircraft mock-up

Laboratory Sessions: Laboratory sessions will provide hands-on experience with modal testing equipment, data acquisition systems, and software for modal analysis. Students will work in teams to conduct experiments and analyze data on a scaled aircraft model

Learning outcomes of the learning unit

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.

Prerequisite knowledge and skills

Fundamentals of Vibrations (course MECA0029)
Mechanical Systems Dynamics
Basic knowledge of the finite element method
Basic Knowledge of Signal Processing and MATLAB/Python

Planned learning activities and teaching methods

The lab sessions are organised in groups and upon appointment only.
The assistant leads the first session, which 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:

the detailed description of the measurements made in the laboratory on the test structure,
the development and application of two modal parameter identification methods (mode, frequency and damping) of the structure based on the experimental results obtained,
exploitation of a finite element model of the structure tested in the MATLAB/PYTHON and Siemens NX
the qualitative and quantitative comparison between theoretical and experimental results.

The lab sessions are MANDATORY. Any unjustified absence may lead to the refusal of participation in the final exam.

Mode of delivery (face to face, distance learning, hybrid learning)

Face-to-face course

Course materials and recommended or required readings

Platform(s) used for course materials:
- eCampus

Further information:

The lecture notes and the course slides are available online on ecampus. The notes and the slides are regularly updated and will be available before each lecture.

Recommended references:

P. Avitabile, Modal Testing: a Practitioner's guide, Wiley, 2018, ISBN 1119222893
D. J. Ewins, Modal Testing: Theory, Practice and Application, Research Studies Press Ltd., 2000, ISBN 0-86380-218-4

Exam(s) in session

Any session

- In-person

written exam ( open-ended questions ) AND oral exam

Written work / report

Further information:

The final grade will be based on the project report, its presentation and the written 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). An oral presentation will be organised at the end of the project.

2. The written exam will consist in answering to questions related to the theoretical concepts presented during the lectures. No document is allowed for the exam.

Student assessment criteria:

Project report: 75%.
Exam: 25%.

The assessment is based on the weighted geometric average of the project and the exam. The final note is calculated as follows:

Final note = (Project)^(0.75) * (Exam)^(0.25)

Work placement(s)

Organisational remarks and main changes to the course

The course's organisation is presented in detail during the first lecture.

Contacts

Loïc Salles l.salles@uliege.be

Assistant: Olivier Devigne o.devigne@uliege.be

Vibration testing and experimental modal analysis