Showing papers by "Shaikh Faruque Ali published in 2021"

Dynamics of symmetric and asymmetric potential well-based piezoelectric harvesters: A comprehensive review:

Abstract: Small and micro-scale energy harvesting is an essential and viable option for the powering of portable and maintenance free electronic devices, wireless sensor nodes, and similar applications. In t...

Studies on large deflection of geometrically nonlinear corrugated structures

Abstract: This manuscript proposes an iterative scheme for geometrically large deflection analysis of corrugated structures using the nonlinear shooting method. The corrugated structure is modeled by discretizing it in several corrugated units. The solution of each unit is obtained assuming it to be consistering of several beam elements. Finally, the deflection of a corrugated structure is calculated assembling the deflection of each of the corrugated units. The formulation has been extended to various boundary conditions (fixed–fixed and fixed–hinged) and loading conditions (point loads and uniformly distributed load). This shows the versatility of the methods in solving various problems. Furthermore, two prototypes of the corrugated structure are fabricated using aluminum and carbon fiber reinforced polymer (CFRP) laminate, and a moment actuation test is performed. The deflections of these prototypes obtained using the proposed iterative scheme are compared with the numerical model and validated with experiments, and results are found to be in good agreement.

Parametric Uncertainty and Random Excitation in Energy Harvesting Dynamic Vibration Absorber

Abstract: An energy harvesting dynamic vibration absorber (EHDVA) is studied to suppress undesirable vibrations in a host structure as well as to harvest electrical energy from vibrations using piezo...

Nonlinear dynamics and control of helicopter ground resonance

Abstract: Ground resonance is an aero-mechanical instability in helicopters that use soft in-plane rotors. Traditionally, ground resonance is mitigated by using passive lead–lag dampers that provide sufficie...

Harvesting Energy from a Series of Harvesters

Abstract: Increase in usage of small electronics and environment threat that batteries provide have accelerated the research in energy harvesting in the last decade. The main challenges in energy harvesting are to increase the operating frequency bandwidth of harvesters and to increase the amount of power harvested. Multiple tuned harvesters have gained a lot of attention in alleviating these challenges. Attaining perfect tuning is a challenge and mistuning is inherent in systems. This study looks into the effect of mistuning in a set of harvesters that are designed to be perfectly tuned. The harvester set is considered to be a set of nonlinear oscillators that represent pendulum-based energy harvester. Four different arrangements among the oscillators are considered. These are (a) series of independent harvesters, (b) series of independent but mistuned harvesters, (c) interacting harvesters, and (d) interacting but mistuned harvesters. In all these cases, base excitation is imparted to the system and physics of the system is studied. It is observed that in the mistuned cases bandwidth is larger when compared to the tuned cases.

Design of a Flow Control Device Using a Special Class of Hybrid Symmetric Bistable Laminates in Clamped Boundary Condition

Abstract: In this manuscript, a concept flow control valve is designed, exploiting the bistable characteristics of a special class of hybrid laminates made of glass epoxy and carbon epoxy prepregs. The principal structural element of the device is a hybrid bistable laminate, having a multi-section layup laid in a symmetric configuration. The thermal curing process responsible for the inherent bistability is simulated in ABAQUS\(^{\textregistered }\) and the equilibrium shapes hence obtained using the FEA scheme is validated against an existing semi-analytical technique based on the Rayleigh-Ritz minimization of potential functional. These multi-stable elements are then studied for their potential in controlling a flowing stream. Toward that, the snapping response of these laminates in a flow stream is analyzed using a combination of XFOIL and ABAQUS\(^{\textregistered }\). The pressure distribution on the laminate is estimated using XFOIL, which is an interactive program for analysis of subsonic isolated airfoils in viscous/inviscid low Reynolds number flow. The pressure distribution hence obtained is used to evaluate the load-displacement characteristics of the laminate using post-buckling regime analysis capabilities of ABAQUS\(^{\textregistered }\). Using these analysis tools, the design space is explored and the possibility of using the proposed bistable design elements for flow regulation is established.

Design of a Nonlinear Energy Harvesting Dynamic Vibration Absorber

Abstract: 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.

Form factors and two-photon exchange in high-energy elastic electron-proton scattering

Abstract: We report new precision measurements of the elastic electron-proton scattering cross section for momentum transfer squared (Q$^2$) up to 15.75~\gevsq. These data allow for improved extraction of the proton magnetic form factor at high Q$^2$ and nearly double the Q$^2$ range of direct longitudinal/transverse separated cross sections. A comparison of our results to polarization measurements establishes the presence of hard two-photon exchange in the $e$-$p$ elastic scattering cross section at greater than 95\% confidence level for Q$^2$ up to 8 (GeV/c)$^2$.

Deeply virtual Compton scattering using a positron beam in Hall-C at Jefferson Lab

Abstract: We propose to use the High Momentum Spectrometer of Hall C combined with the Neutral Particle Spectrometer (NPS) to perform high precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section using a beam of positrons. The combination of measurements with oppositely charged incident beams is the only unambiguous way to disentangle the contribution of the DVCS$^2$ term in the photon electroproduction cross section from its interference with the Bethe-Heitler amplitude. This provides a stronger way to constrain the Generalized Parton Distributions of the nucleon. A wide range of kinematics accessible with an 11 GeV beam off an unpolarized proton target will be covered. The $Q^2-$dependence of each contribution will be measured independently.

Analysis of Stepped Beam Using Reduced Order Models

Abstract: Damage detection in complicated engineering systems from vibration measurements typically involves the use of algorithms that are built on the principles of bayesian dynamic state estimation. These methods invariably required the solution of the forward problem a fairly large number of times. For complex engineering systems that are numerically modeled using Finite Element (FE), this can be computationally intensive especially when a single FE run for the problem takes a large time. To alleviate this problem, there is a need for the development of Reduced Order Models (ROMs) that significantly reduce the computational cost associated with solving the forward problem, for a given measure without sacrificing the accuracy. The present study discusses three ROM methods with specific reference to a simple problem. These methods include well-known Component Mode Synthesis (CMS) and System Equivalent Reduction Expansion Process (SEREP) which are applicable only for linear systems, as well as Principal Component Analysis (PCA)—the method which is more general and can be used for nonlinear systems as well. A comparison of the performance of all these methods is carried out for a stepped beam. The FE based results obtained from the full model is treated as the benchmark.