Moving Europe forward by building green, smart cities and buildings is of paramount importance in our modern technological and connected/inclusive society. With this in mind, the SmarT-uP project makes a step change in high-rise building design (expected to be the most common building typology in future congested urban areas) subjected to environmental- (e.g. wind-) induced vibrations, by introducing a new breed of tall/slender buildings with macro-scale energy harvesting capabilities for powering diffused wireless sensors provided for building automation (leading to an increment of the building sustainability) and/or for structural-health monitoring (leading to an increase of the building resilience). Specifically, the envisioned structures not only resist effectively wind loads, causing occupants¿ discomfort (loss of serviceability) or damage to non-structural components (loss of integrity) in tall buildings, but they exploit wind-induced vibrations to improve their performance in terms of carbon footprint. This is accomplished by developing piezoelectric-dampers (PiDs) for simultaneous structural elements connection and energy harvesting (EH). The developed PiDs are composite connections (piezoelectric+steel or rubber) engaged by wind-induced oscillations to dissipate the kinetic energy of the oscillating building by transforming it into electric energy stored for powering sensors. In this manner, a proper number of PiDs provided to a building will constitute, as a whole, a parallel power system for sensors¿ energy needs, which is self-powered, cable free (thanks to the wireless technology) and almost maintenance free (absence of cables). These innovative devices will be groundbreaking since they will be able to extend EH techniques from the (currently developed) micro (nano- milli-meters) and meso (centimeters) scales, to the (undeveloped) macro scale (meters).
ADVANCING THE KNOWLEDGE BASE OF DISCIPLINE (tall building design)
A multi-objective optimum design procedure of PiDs-based tall buildings achieving code-compliant structural performance while maximizing the harvested energy for BA and SHM will be defined. The optimum design tall buildings against tailored application-dependent performance criteria uses standard numerical techniques and is well-studied in the literature . On the other side, optimal design of and SHM systems for structures is mainly focused on the optimal placement of sensors. However, the (non investigated until today) problem of optimal design of EH devices in buildings will involves two always conflicting objectives: maintaining vibrations under a certain level and maximizing the harvested energy . In particular, the optimization of the EH system constituted by the diffused PiDs along the building in view of its goal of powering a wireless sensors network will lead to innovative optimization criteria. The novelty is not in the optimization techniques (e.g. optimal sensors¿ placement), but in the criteria for optimization which are based on the self-powering and wireless unique characteristics of the proposed system. This problem is handled in SmarT-uP by appropriate formulation of the PiD-based tall building and sensors design problem, given a benchmark tall building and input loading, aiming to appropriately locate the PiDs (on the basis of input vibrations and sensors location criteria) and to maximize the harvested energy (objective function) and, at the same time, meeting code-compliant structural performance requirements as constraints to the optimization problem. The experience of the PI in optimal SHM, will significantly facilitate this task.
INNOVATIVE TECHNOLOGIES
This project will develop innovative structural energy-producing connections (PiDs) based on the combination of piezoelectric and structural blocks. Conceptual design, analytical and numerical electromechanical modelling of PiDs will be developed in a bottom-up approach (step 2 and 3 in Fig.2). Specific innovation will be the (macro-) scale of these piezoelectric devices, something not developed until now since the use of piezoelectric materials for EH from oscillating civil engineering structures has been hindered by the large magnitude of the involved forces. The developed PiDs overcome this problem by coupling piezomaterials with other materials with mechanical properties (e.g., rubber and steel) which can carry large forces. Advanced FE models and analytical simplified models will be developed for the electromechanical characterization of the PiDs.