Simulation and the monte carlo method

Nonlinear Oscillations: Exact Solutions and their Approximations

High-Performance Piezoelectric Energy Harvesters and Their Applications

The last two decades have witnessed several advances in microfabrication technologies and electronics, leading to the development of small, low-power devices for wireless sensing, data transmission, actuation, and medical implants. Unfortunately, the actual implementation of such devices in their respective environment has been hindered by the lack of scalable energy sources that are necessary to power and maintain them. Batteries, which remain the most commonly used power sources, have not kept pace with the demands of these devices, especially in terms of energy density. In light of this challenge, the concept of vibratory energy harvesting has flourished in recent years as a possible alternative to provide a continuous power supply. While linear vibratory energy harvesters have received the majority of the literature’s attention, a significant body of the current research activity is focused on the concept of purposeful inclusion of nonlinearities for broadband transduction. When compared to their linear resonant counterparts, nonlinear energy harvesters have a wider steady-state frequency bandwidth, leading to a common belief that they can be utilized to improve performance in ambient environments. Through a review of the open literature, this paper highlights the role of nonlinearities in the transduction of energy harvesters under different types of excitations and investigates the conditions, in terms of excitation nature and potential shape, under which such nonlinearities can be beneficial for energy harvesting. [DOI: 10.1115/1.4026278]

On the Role of Nonlinearities in Vibratory Energy Harvesting: A Critical Review and Discussion

Thank you for reading stochastic processes and filtering theory. Maybe you have knowledge that, people have look numerous times for their favorite novels like this stochastic processes and filtering theory, but end up in harmful downloads. Rather than reading a good book with a cup of tea in the afternoon, instead they are facing with some infectious bugs inside their computer. stochastic processes and filtering theory is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library saves in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the stochastic processes and filtering theory is universally compatible with any devices to read.

Stochastic Processes And Filtering Theory

This manuscript deals with the creation and stabilization of limit cycles in the Lorenz attractor with the help of orbit closure technique. Chaos control techniques such as the OGY and OPF techniques apply small perturbations to a system parameter to stabilize an unstable periodic orbit present in a chaotic attractor. But it may happen that the system parameters may not be available for control. For example, in structural systems, it is difficult to alter their geometry and material properties in real-time, so as to suppress chaos. In such cases, use of state feedback control will provide ease of implementation. The orbit closure technique is a novel method of controlling chaos wherein a finite time control effort is applied to the system states, once per period, to bring back the chaotic trajectory to a desired periodic orbit so as to stabilize it. In this manuscript, the orbit closure technique is applied to create and stabilize limit cycles of different time periods in the Lorenz attractor. The control effort required for closure of the orbits is provided through feedback linearization. As a pilot study, the efficacy of the proposed technique is demonstrated through numerical simulations in this manuscript. Further, the influence of the control gain on the shape and time period of the stabilized orbit is studied and reported.

Stabilization of limit cycles in the Lorenz attractor through the orbit closure method

Control of Transient Coupled Radiative-conductive Heat Transfer Equation

The study focuses on the design of an energy harvesting nonlinear dynamic vibration absorber (DVA) for possible vibration attenuation and energy generation. As an application vibration mitigation of a base-excited single degree of freedom (SDOF) system is considered. Conventional DVAs are widely used as vibration control devices that undergo large displacements in order to dissipate the energy from the primary structure. For an energy harvester higher the vibration higher is the energy generated. Therefore, if an energy harvester is attached to the DVA, the primary structure DVA interaction can be used for dual purposes. In this study, a duffing-type nonlinear DVA system with a piezo patch is proposed as energy harvesting nonlinear DVA to mitigate the vibration and to obtain electricity. The modeling of the total system is carried out considering the electromechanical interactions between the harvester-DVA and structural system. The formulation is done in time domain and a simulation study is carried out for harmonic base excitation to understand the effect of nonlinearity in voltage generation. A frequency sweep study is carried out to locate the frequency band in which the system responses are consistently higher. Further, the important design parameters are identified. A parametric study to obtain optimal design parameters is also reported. The advantages of nonlinear energy harvesting DVA over the linear ones are many. A nonlinear harvester provides power over a broad range of frequencies and, therefore would be able to dissipate energy from the primary structure over wideband excitations. Finally, the performance of the designed nonlinear DVA system with harvester is examined for vibration mitigation of SDOF primary system.

Design of a Nonlinear Energy Harvesting Dynamic Vibration Absorber

This study focusses on the vibration control of linear large scale engineering structures, modelled as continuous system, with varying system parameters. Because of manufacturing limitations or/and measurement errors, system parameters need to be modelled as random variables. Here, system parameters are modelled as non-Gaussian random variables. Mathematically, continuous system is governed by partial differential equations and solved using approximation methods. High fidelity finite element model is the starting point of the analysis. Since numerical approximation involves large number of degrees-of-freedom, solving the system in real time is computationally expensive and application of control algorithm is cumbersome. In this study, a reduced order model is developed to reduce the state space dimension of the problem and further integrated with the control algorithm. Next, controller gain is obtained using linear quadratic regulator in reduced subspace which is used as a feedback to the actuators to produce the required control force for vibration control. A numerical example of flexible cantilever beam is solved to demonstrate the efficacy of the algorithm and probabilistic characterisation is carried out using Monte Carlo simulation.

ROM integrated vibration control of stochastically parametered flexible structures

This paper presents active morphing and vibration control of thin cantilever plates using an array of piezoelectric sensor and actuator system The piezoelectric actuators and sensors are used to form a feedback control loop to suppress the undesired vibrations caused during configuration change Dynamic Inversion technique is used to determine the control variables to morph the plate and suppress its vibrations The partial differential equations governing the plate deformation and piezoelectric actuation are solved using projection method to obtain algebraic equations, following Design-then-Approximate (DTA) method Two configurations are considered from its eigenspace to perform simulations The actuators are designed for both morphing and vibration control since thin plates have poor damping characteristics and need external damping The displacement norm and velocity norm time histories and the configuration achieved by the system are analysed

Shaikh Faruque Ali

Papers

Stabilization of limit cycles in the Lorenz attractor through the orbit closure method

Control of Transient Coupled Radiative-conductive Heat Transfer Equation

Design of a Nonlinear Energy Harvesting Dynamic Vibration Absorber

ROM integrated vibration control of stochastically parametered flexible structures

Active vibration control and shape morphing of thin plates using dynamic inversion technique