The SMARTECH project will initiate innovative devices called piezoelectric-dampers (PiDs) to be embedded in modern tall buildings for simultaneous structural elements connection and energy harvesting (EH). PiDs are composite elements (piezoelectric+steel and rubber) located in the connections between structural members (e.g. columns and beams) and engaged by wind-induced oscillations to transform the kinetic energy of the vibrating structure into electricity. This will be possible thanks to the embedment of piezoelectric materials in PiDs. In fact, if subjected to forces, piezoelectric materials generate electric charges proportionate to strain amplitude and vibration frequency induced by that force.
The concept of PiD this will scale-up currently developed piezoelectric EH (pzEH) techniques at the micro and meso scales to the truly macro scale. pzEH devices have never been implemented as structural connections in civil structures for a number of reasons, such as the inadequacy of piezo materials in carrying loads and low frequencies of the vibrations occurring in buildings. These will be comprehensively addressed in SMARTECH by innovative in-parallel coupling schemes between piezo and the load carrying members such as steel or rubber members, and by allowing the piezo-blocks working in nonlinear/high-frequency regimes arising from buckling or impact. These features will allow their implementation in buildings for powering wireless sensors provided for building automation (BA), which leads to an increment of the building sustainability, and for structural-health monitoring (SHM). The SMARTECH project makes a step change in civil engineering structures design and management, by defining a new breed of SMART structures (SSs) with self-powering, adaptive-in-behavior capabilities. These structures not only resist loads, but they exploit wind-induced vibrations to reduce their carbon footprint and improve their performances.
1) Innovative devices/technology. EH-enabled composite PiDs connections in dynamically excited tall buildings using piezo-materials. Conceptual design and electromechanical modelling of PiDs will be conducted by a bottom-up approach. Novel aspects in PiDs conception are: i) their nonlinear functionality (buckling or impact dynamics); ii) their macro-scale (coupling piezomaterials with materials carrying large forces, e.g. rubber, steel). These aspects will bridge current knowledge gaps hindering usage of pzEH in civil structures, and will lead to the following ground-breaking expected results:
- revolutionary unconventional structural connections will be developed;
- access of civil engineers to piezoelectric as new, smart, construction material will be facilitated.
2) Novel, approaches/methods for Civil Engineering design by the definition of a novel multi-performances approach for PiDs-equipped tall buildings for code-compliant structural performance against service and extreme/accidental loads and EH maximization towards energy autonomous BA and SHM. PBD of tall buildings is one of the primary research areas for the PI and collaborators. Further, optimal design of SHM systems involves optimal placement of sensors in a given structure irrespective of available power source locations and/or optimal data sampling and wireless transmission. However, SMARTECH addresses a significantly different problem from the above (not addressed before since PiDs or any other similar technology did not exist) involving the optimal placement of PiDs (based on stress concentration and optimal sensors location criteria) to maximize EH (objective function) while meeting code-prescribed performance requirements (taken as constraints) for wind forces. The novelty lies in the optimization criteria which are based on the diffuse self-powering and wireless unique characteristics of the proposed system. This point will lead to the following ground-breaking expected results:
- a new analytical, multidisciplinary (electro-mechanical) theory representing the behavior of PiDs in large-scale structure will be formulated;
- a new breeds of smart energy-autonomous structures will change the way of designing, constructing and perceiving civil engineering structures;