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

Nonlinear flutter of 2D variable stiffness curvilinear fibers composite laminates by a higher-order shear flexible beam theory with Poisson’s effect

In the present study, the combined effects of thermal and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated beams are numerically analyzed. The finite element modelling of laminated composite beams and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the finite element analysis (FEA) is demonstrated by comparing the experimental test results obtained due to mechanical loadings under the influence of thermal environment with those derived using the present FEA. Various parametric studies are also performed to investigate the effect of thermal loading on interlaminar stresses generated in symmetric, anti-symmetric, asymmetric, unidirectional, cross-ply, and balanced composite laminated beams of different stacking sequences with identical mechanical loadings and various boundary conditions. It is shown that the elevated thermal environment lead to higher interlaminar shear stresses varying with the stacking sequence, length to thickness ratio, ply orientations under identical mechanical loading and boundary conditions of the composite laminated beams. It is realized that the magnitude of the interlaminar stresses along xz plane is always much higher than those of along yz plane irrespective of the ply-orientation, length to thickness ratios and boundary conditions of the composite laminated beams. It is also observed that the effect of thermal environment on the interlaminar shear stresses in carbon-epoxy fiber reinforced composite laminated beams are increasing in the order of symmetric cross-ply laminate, unidirectional laminate, asymmetric cross-ply laminate and anti-symmetric laminate. The interlaminar shear stresses are higher in thinner composite laminated beams compared to that in thicker composite laminated beams under all environmental temperatures irrespective of the laminate stacking sequence, ply-orientation and boundary conditions.

Investigation on interlaminar shear stresses in laminated composite beam under thermal and mechanical loading

The paper proposes experimental method to characterize the Magnetorheological (MR) damper for realization of the suspension control for multi-axle military vehicle. An ac-curate model of MR damper based on the laws of physics to be embedded in real time controller for suspension system increases the computational load and implementation intricacies attracting higher costs and attendant issues. This paper presents a novel practical based approach to characterize MR dampers using simple experimental set up which, additionally, with the help of simulation technique, aids to assess the dynamic range of MR damper for various parameters of suspension system for vibration control in respect of multi-axle vehicle vehicles. The paper reports experimental investigation for characterization of MR damper through quarter car model. Equivalent damping coefficient is estimated using work diagrams. The governing equations of a quarter car model are formulated analytically and the damping coefficients obtained by experimental investigation have been used for simulation study. Performance analysis in terms of body acceleration, amplitude gain, suspension working space and normalized tyre forces has been carried out. The analysis reveals that with variation of current, there is effective reduction in amplification of the sprung mass displacement at the sprung mass fundamental frequency and improvement in ride comfort. Proposed approach is helpful to achieve better controllability of the MR damper without re-lying on the software based techniques for accounting the behaviour of MR fluid. The method finds practical application for implementation in military multi-axle vehicles.

MR Damper Characterization for Implementation of Semi-active Suspension Control

In this study, nonlinear buckling response of composite sandwich semi-ellipsoidal shell subjected to uniform hydrostatic external pressure is investigated numerically and experimentally. The face sheet of the sandwich shell is made up of laminated composite layers and the honeycomb core is considered as reinforced with and without strips. The various honeycomb core configurations with strip reinforcements are employed in the sandwich semi-ellipsoidal shell. The numerical buckling analysis of the sandwich shell is performed using the commercially available software ANSYS®. The geometric nonlinearity and material nonlinearity of the shell structures are included through the arc length method while solving the nonlinear differential equations and identifying the critical pressure of the structure. The efficacy of the numerical modeling and analysis are verified by comparing the critical pressure obtained through the experimental investigations performed on a composite semi-ellipsoidal sandwich shell and results available in the literature. The various parametric investigations are performed on the composite sandwich shell to study the effect of honeycomb configurations, ply orientation of face sheets, aspect ratio and slenderness of the structure, geometric imperfections on the critical pressure. It was seen that the semi-ellipsoidal sandwich shell having double strip reinforcement core yields higher critical pressure among the various configurations of honeycomb cores. However, the semi-ellipsoidal sandwich shell with the single strip reinforcement in between the core having [0°]6s face sheet composite ply configuration yields higher stiffness to weight ratio which leads to the highest critical pressure among the various configurations of sandwich shell. 

Nonlinear buckling analysis of a sandwich composite semi-ellipsoidal shell under hydrostatic pressure: A numerical and experimental investigation

In this study, experimental investigations carried out to analyze the influences of different in-plane temperature variations on buckling and free vibration responses of metal and fiber-reinforced ...

Vasudevan Rajamohan

Papers

Nonlinear flutter of 2D variable stiffness curvilinear fibers composite laminates by a higher-order shear flexible beam theory with Poisson’s effect

Investigation on interlaminar shear stresses in laminated composite beam under thermal and mechanical loading

MR Damper Characterization for Implementation of Semi-active Suspension Control

Nonlinear buckling analysis of a sandwich composite semi-ellipsoidal shell under hydrostatic pressure: A numerical and experimental investigation

Modal analysis of cylindrical panels at elevated temperatures under nonuniform heating conditions: Experimental investigation: