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Vibrations and Acoustics 2019-2020 10. Research Topics

10/12/2019

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Research topics in Structural Dynamics at ULB

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Mechanical Engineering Civil Engineering

Prof A. DeraemaekerProf C. Collette

• Develops instrumentation and strategies for actively measuring and controlling the vibrations of structures.

• Internationally renown expertise in high precision control of large instruments dedicated to experimental physics:• gravitational wave detectors• particle colliders• segmented ground and space telescopes• satellites and light sources

Prof C. ColletteProf A. Deraemaeker

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Active isolation Active Damping

𝐹 Actuator

Sensor

Tools and methods

Numercialmechatronic

s models

Design and fabrication of prototypes

Vibration testing

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𝐹 Actuator

Sensor

Source of disturbance: drone

System to be stabilized: camera

Drone

CameraQuality of the images captured affected by the

vibrations from the drone

Solution: Active isolation

Image to be captured

Conventional system uses passive isolation

Passive isolation degrades the high frequency performance

Active isolation of drone cameras

[Mohit Verma]

• Single-axis isolation system (1 dof) • Multi-axis isolation system (6 dof)

Active isolation of drone cameras

[Mohit Verma]

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Active isolation in gravitational wave detectors

Gravitational waves

Principle of a gravitational wave detector

6 dofs isolation system developed

[Jennifer WatchiBinlei DingGuoying Zhang]

High precision / Low frequency sensors

Commercial sensor PML sensor

- High precision interferometer- Under vacuum (low damping)- Low resonant frequency

[Binlei Ding]

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Translation/tilt gravity decoupling

laser postion detector

(laser spot motion)

laser source

Beam splitter

Tilted surface

Original reflecting surface (tilting angle)

[Binlei Ding]

• Disturbances from rotations/translations

• Active hexapod to reject disturbances

Active rejection of disturbances at a nano-metric level

[Thomas Dehaeze]

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Damping of bladed structures

Light weight/low dampingVibrations -> Fatigue / noise radiation

Active vibration damping

Optimal control laws for linear systems

[Ahmad Paknejab,Guoying Zhao]

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Optimal control laws for non-linear systems


Non-linear active control

Linear active conrol

Hybrid vibration control


• Failsafe• Low power consumption

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Optimisation of mechatronics systems

• Sensors and actuator types/positions ?• Control strategy ?

• Integrated mechatronics models• Robust optimisation strategies

[Shashank Pathak,Dimitri Piron]

Develops instrumentation and strategies for wave-based structural health monitoring of concrete structures and vibration damping with special emphasis on :

• Numerical modeling of piezoelectric structures• Piezoelectric transducers development• SHM data processing and decision algorithms• Design of tuned mass dampers

Prof A. Deraemaeker

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Tools and methods

Numercialmodels

Design and fabrication of prototypes

Testing

Piezoelectric module co-developed with SDTools (E. Balmès)

3D elements Multi-layer plate elements

The Structural Dynamics Toolbox (under Matlab)

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The Structural Dynamics Toolbox (under Matlab)

Complex models(1 million+ DOFS.)

Embedded piezoelectric transducers

Modeling of embedded piezoelectric transducers for concrete monitoring

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Modeling of embedded piezoelectric transducers for concrete monitoring

• Improved transducers (patent)• Development of shear wave transducers• Improvement of wave propagation models in concrete

Structural Health Monitoring

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Wave-based Structural Health Monitoring

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Wave-based Structural Health Monitoring

Application in the Rogier Tunnel in Brussels

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Application in the Rogier Tunnel in Brussels

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Tuned vibration absorbers

Variability due to the environment (T°, humidity)• Effect on performance of TMD ?• Robust design of TMD ?

Other criteria for optimisation• Response spectra• Realistic input spectra (wind, earthquake)

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