Energy harvesting technologies have been explored by researchers for more than two decades as an alternative to conventional power sources (e.g. batteries) for small-sized and low-power electronic devices. The limited life-time and necessity for periodic recharging or replacement of batteries has been a consistent issue in portable, remote, and implantable devices. Ambient energy can usually be found in the form of solar energy, thermal energy, and vibration energy. Amongst these energy sources, vibration energy presents a persistent presence in nature and manmade structures. Various materials and transduction mechanisms have the ability to convert vibratory energy to useful electrical energy, such as piezoelectric, electromagnetic, and electrostatic generators. Piezoelectric transducers, with their inherent electromechanical coupling and high power density compared to electromagnetic and electrostatic transducers, have been widely explored to generate power from vibration energy sources. A topical review of piezoelectric energy harvesting methods was carried out and published in this journal by the authors in 2007. Since 2007, countless researchers have introduced novel materials, transduction mechanisms, electrical circuits, and analytical models to improve various aspects of piezoelectric energy harvesting devices. Additionally, many researchers have also reported novel applications of piezoelectric energy harvesting technology in the past decade. While the body of literature in the field of piezoelectric energy harvesting has grown significantly since 2007, this paper presents an update to the authors' previous review paper by summarizing the notable developments in the field of piezoelectric energy harvesting through the past decade.

https://iopscience.iop.org/article/10.1088/1361-665X/ab36e4/pdf

A review of energy harvesting using piezoelectric materials: state-of-the-art a decade later (2008–2018)

Stereolithography is a solid freeform technique (SFF) that was introduced in the late 1980s Although many other techniques have been developed since then, stereolithography remains one of the most powerful and versatile of all SFF techniques It has the highest fabrication accuracy and an increasing number of materials that can be processed is becoming available In this paper we discuss the characteristic features of the stereolithography technique and compare it to other SFF techniques The biomedical applications of stereolithography are reviewed, as well as the biodegradable resin materials that have been developed for use with stereolithography Finally, an overview of the application of stereolithography in preparing porous structures for tissue engineering is given

A review on stereolithography and its applications in biomedical engineering

Variable stiffness material and structural concepts for morphing applications

Review: A review of active structural control: challenges for engineering informatics

Fused deposition modeling-based additive manufacturing (3D printing): techniques for polymer material systems

Abstract In this work, a comprehensive investigation of curvilinear fiber reinforcement on damping of rectangular and skew composite plates is computationally estimated using higher-order shear flexible model. A set of governing equilibrium equations developed here in form of eigenvalue analysis is solved by adopting the Q-R algorithm. The damping factors associated with different vibrational modes are evaluated from the complex eigenvalues. The proposed model is validated against the available analytical and experimental results. The damping capability of laminated rectangular/skew composite plates is thoroughly analyzed by varying the curvilinear fiber path angles in the layers, lay-up orientations, structural boundary conditions, skew angle of the laminate, and nature of the material. Results reveal that the damping pretending to the curvilinear fibers plate is better than the conventional composite laminate; it varies significantly according to the variation in center and edge of the curvilinear fiber angles. It is also noted that the damping increases with the skew angle of the plate. The study conducted here shows the suitability of such variable stiffness composite structure for safe design under dynamic/impact loading situation.

A comprehensive damping study of variable stiffness composite rectangular/skew laminates reinforcement with curvilinear fibers by higher-order shear flexible model

A design optimization methodology is presented to maximize the modal damping factor of a partially treated MR sandwich beam. Modal strain energy approach has been implemented in the finite element model developed for a partially treated MR sandwich beam to derive the modal damping factor at each node. Two different configurations of a partially treated MR sandwich beam are considered including a beam with a cluster of MR fluid segments and a beam with arbitrarily located MR fluid segments. The significance of the location of MR fluid segments on the modal damping factor is investigated under different end conditions. The design optimization problem is formulated by combining the finite element method with optimization based on genetic algorithm (GA) to identify the optimal location of the MR fluid segments to maximize the modal damping factor for the first five modes individually under various end conditions. The results suggest that the optimal location of the MR fluid treatment is strongly related not only to the end conditions but also to the mode of vibration.© 2010 ASME

Optimal Location of the MR Fluid Segments in the Partially Treated Magnetorheological Fluid Sandwich Beam

The present study is focused on the numerical and experimental investigation of the non-linear buckling behavior and ply-failure analysis of a hybrid composite shell under uniform hydrostatic pressure exposed on its outer surface. Laminated composite shells made of glass fiber reinforced polymer (GFRP) composites with and without multi-walled carbon nanotubes (MWCNT) reinforcement are considered for the investigation. The critical buckling pressure is numerically determined by performing a buckling analysis on a hybrid composite shell with consideration of various non-linearities such as material non-linearity, geometric non-linearity, and geometric imperfection using the commercially available software ANSYS®. The governing non-linear differential equations of composite shell structures are solved using the arc-length approach and non-linear finite element analysis. The nanotubes dispersion, distribution, structural integrity, aspect ratio, functional group, and purity level of CNT reinforcement with epoxy matrix materials are quantified using field emission scanning electron microscopy (FE-SEM). The elastic and plastic properties of the GFRP lamina with and without MWCNT reinforcement are experimentally determined based on ASTM D3039. The critical buckling pressure obtained through experiments on a GFRP composite shell with and without MWCNT reinforcement is compared with the results obtained from the numerical analysis to validate the effectiveness of the present numerical model. Parametric studies are undertaken to investigate the first ply failure analysis, the effect CNT reinforcement, aspect ratio of MWCNT, and different lamination sequences on the critical buckling pressure of the composite shell. It was observed that the Von-Misses stresses developed on the composite structures with ply angles of either all layers as 0° or combination of ply angles with 0° and 90° is always less than those of the structures having ply-angles such as 45° and 60°, irrespective of CNTs reinforcement. Furthermore, the highest critical buckling pressure was obtained with reinforcement of 1.5 wt% MWCNT in the composite shell with ply orientation of [90°]4s. 

Non-linear buckling analysis of MWCNT reinforced hybrid composite shell subjected to hydrostatic pressure: A numerical and experimental investigation

In the present study, a numerical and experimental investigation is carried out on vibration-based energy harvesting from unimorph cantilever tapered composite beams. A uniform and various configurations of a tapered composite structure embedded with piezoelectric material are considered to identify the electrical energy generated by the piezoelectric material when dynamic energy is imparted on the structure. Lead zirconate titanate (PZT) of 5-H grade piezoelectric material is considered to be embedded on a cantilever beam made of glass fiber reinforced polymer matrix composite. The numerical modeling and analysis are performed on the composite structure embedded with PZT to calculate the total amount of electrical energy that can be generated by the PZT material using commercially available ANSYS APDL software. Various parametric studies are also carried out to investigate the effects of varying the location of the PZT patch and the configuration of the PZT patches on the electrical energy developed by the PZT. Further, the power generated through unimorph composite structure with PZT material connected in series and parallel are explored. 

Vasudevan Rajamohan

Papers

A comprehensive damping study of variable stiffness composite rectangular/skew laminates reinforcement with curvilinear fibers by higher-order shear flexible model

Optimal Location of the MR Fluid Segments in the Partially Treated Magnetorheological Fluid Sandwich Beam

Non-linear buckling analysis of MWCNT reinforced hybrid composite shell subjected to hydrostatic pressure: A numerical and experimental investigation

Modeling and analysis of tapered composite beams with piezoelectric energy harvester: Numerical and experimental investigations