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EU

Funded by the European Union

Work packeages: WP 1WP 2WP 3WP 4WP 5WP 6

WP 3 Structural Adaptation Strategies

Structural adaptation through prestressing of composites: As reported in WP2, a technique for optimization of selected prestress parameters in prestressed composites has been developed. Besides prestress identification, such a technique can be used for design optimization and prestress adaptation in three application areas:
  • reduction of stresses in lightweight decks of pedestrian bridges,
  • reduction of stresses in cylindrical shell structures loaded by internal pressure (pressure tanks, barrels, etc.),
  • fast pneumatic valves based on a controlled snap-through effects for real-time structural adaptation.
A concept of a fast pneumatic valve based on a prestressed composite and a controlled snap-through effect has been proposed. A natural application area are adaptive pneumatic fenders for protection of maritime installations and vessels.

Structural vibroacoustics: The improving the efficiency of the structural vibroacoustics control solutions is being addressed through the following main aspects:
  • energy management : energy harvesting for self-sustainable systems, vibration control strategy,
  • self switching between control strategy : passive, semi-active, signal tuned, broad-band,
  • transient signals / harmonic forces
  • distributed array of sensors,
  • remote sensing area.
Each of these aspects consider an electro-mechanical solution. However, before performing as an adaptive solution, each shall be adapted to the type of physical phenomena, the structure and its environment:
  • energy management : available forms of energy either externally supplied or locally available in the physical phenomena to be controlled (strain energy, acoustic disturbance, temperature gradients), energy management between harvesting and re-used form or time delay.
  • transient signals / harmonic forces : narrow- or broad-band and distributed array of sensors: design of smart grids of de-centralized structural control system that could operate globally or by means of clustered distributed controlling nodes.
In the scope of the project, a secondee has performed a review and studied the design of tuned and broad-band local vibration control strategies for propagative waves in slender structures or components with identified energy flow paths. The research was focused on shunted piezoelectric patches for wave propagation control, possibly with an unknown excitation source, and energy management. A natural further step would be the research on electro-mechanical decentralized and clustered vibroacoustics sensing array for varying time signal disturbances (measurement treatment, indicators and threshold definition for solution selection and adaptation).

The intended goals are:
  • definition of local self-sustainable and self-processing electro-mechanical nodes (principle, architecture, performance). It should have the ability to switch between passive or semi-active depending on the narrow or broad-band input signal, whether transient or continuous.
  • definition, prototype manufacturing and experimental assessment of adaptative vibration surveying grids. The solution shall be based on a local information processing and a low consumption radio-frequency communication protocol.