Ambient vibrations are major source of wasted energy, exploiting properly such vibration can be converted to valuable energy and harvested to power up devices, i.e. electronic devices. Accordingly, energy harvesting using smart structures with active piezoelectric ceramics has gained wide interest over the past few years as a method for converting such wasted energy. This paper provides numerical and experimental analysis of piezoelectric fiber based composites for energy harvesting applications proposing a multi-scale modeling approach coupled with experimental verification.The multi-scale approach suggested to predict the behavior of piezoelectric fiber-based composites use micromechanical model based on Transformation Field Analysis (TFA) to calculate the overall material properties of electrically active composite structure. Capitalizing on the calculated properties, single-phase analysis of a homogeneous structure is conducted using finite element method. The experimental work approach involves running dynamic tests on piezoelectric fiber-based composites to simulate mechanical vibrations experienced by a subway train floor tiles. Experimental results agree well with the numerical results both for static and dynamic tests.

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This current study focuses on utilizing Composite Materials with Embedded PZT Filaments for Energy Harvesting. It represents a multi-scale approach to model embedded PZT filaments in polymer based composite material. The work presented models multifunctional composite materials and structures on multiscales considering piezoelectric response to mechanical loads for the reinforcement of unidirectional composites, which are used to construct laminates of a general layup; both membrane and bending vibrational loads are considered.The solution for the local fields is determined in terms of a transformation field analysis scheme in which the local stresses or strains, which are cannot be removed by mechanical unloading are treated as eigen fields applied in an otherwise elastic medium. In the current application, the latter represents an aggregate of unidirectional plies and their phases. Both two phase models such as the Mori-Tanaka model and periodic array models are employed. The solution for the overall response is determined in terms of refined plates theory using Carrera unified formulation. The overall electro-mechanical properties used are obtained from the transformation field analysis conducted earlier.The proposed modeling strategy is applied to fibrous laminates subjected to mechanical loads. These results were then verified experimentally by using piezoelectric ceramic composites. These smart structures will be an important component in future designs of energy harvesting and multi-functional devoices to increase efficiency and recover energy.---

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The complexity of engineering structures dictates a paradigm shift from traditional inspection and damage detection techniques to more reliable and efficient approach. Smarts materials such as piezoelectric materials are being studied as onboard sensors to detect damage progression inside composite structures. Nevertheless, predictive models of such complex structures coupled to piezoelectric materials been absent, especially related to damage detection and prediction. In the current study, a multi-scale approach is suggested to predict the behavior of piezoelectric fiber-based composites. Micromechanical model based on transformation field analysis is described to quantify the overall material properties of electrically active composite structure. Capitalizing on the extracted properties, single-phase analysis of a homogeneous structure is conducted using Carrera Unified formulation; a refined plate theory extended to include electric behavior of active materials. Results obtained here are validated against experimental results. Furthermore, the impact of damage on local and global fields is evaluated on macro-level through simulated voids inside a beam-like structure. KEY WORDSPiezoelectric, composites, and damage identification.---