Nonlinear Oscillations: Exact Solutions and their Approximations

Pull-in instability as an inherently nonlinear and crucial effect continues to become increasingly important for the design of electrostatic MEMS and NEMS devices and ever more interesting scientifically. This review reports not only the overview of the pull-in phenomenon in electrostatically actuated MEMS and NEMS devices, but also the physical principles that have enabled fundamental insights into the pull-in instability as well as pull-in induced failures. Pull-in governing equations and conditions to characterize and predict the static, dynamic and resonant pull-in behaviors are summarized. Specifically, we have described and discussed on various state-of-the-art approaches for extending the travel range, controlling the pull-in instability and further enhancing the performance of MEMS and NEMS devices with electrostatic actuation and sensing. A number of recent activities and achievements methods for control of torsional electrostatic micromirrors are introduced. The on-going development in pull-in applications that are being used to develop a fundamental understanding of pull-in instability from negative to positive influences is included and highlighted. Future research trends and challenges are further outlined.

Electrostatic pull-in instability in MEMS/NEMS: A review

Nonlinear behaviour of electrically actuated MEMS resonators

Free vibration of size-dependent Mindlin microplates based on the modified couple stress theory

In order to address the key problems faced by small- and medium-sized enterprises (SMEs), existing solutions and shortcomings were analyzed. The possibilities by using the new emerged technologies and theories (e.g., cloud computing, internet of things, service-oriented technology) to solve the bottlenecks faced by SMEs are investigated. The idea of manufacturing resource and capability sharing based on cloud computing for SME is discussed, and an SME-oriented cloud manufacturing service platform (SME-CMfgSP) is introduced. The architecture of SME-CMfgSP is proposed, and the key technologies for implementing SME-CMfgSP are introduced in details. The challenges for implementing cloud manufacturing service platform for SMEs were discussed. A case study is described to illustrate the application of the proposed SME-CMfgSP.

Cloud manufacturing service platform for small- and medium-sized enterprises

A large deflection model for the pull-in analysis of electrostatically actuated microcantilever beams

Engine performances and emission characteristics of Karanja oil methyl ester blended with diesel were carried out on a variable compression diesel engine. In order to search for the optimal process response through a limited number of experiment runs, application of Taguchi method in combination with grey relational analysis had been applied for solving a multiple response optimization problem. Using grey relational grade and signal-to-noise ratio as a performance index, a particular combination of input parameters was predicted so as to achieve optimum response characteristics. It was observed that a blend of fifty percent was most suitable for use in a diesel engine without significantly affecting the engine performance and emissions characteristics.

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Optimization of Performance and Emission Characteristics of Diesel Engine with Biodiesel Using Grey-Taguchi Method

This study analyses the nonlinear transverse vibration of an axially moving beam subject to two frequency excitation. Focus has been made on simultaneous resonant cases i.e. principal parametric resonance of first mode and combination parametric resonance of additive type involving first two modes in presence of internal resonance. By adopting the direct method of multiple scales, the governing nonlinear integro-partial differential equation for transverse motion is reduced to a set of nonlinear first order ordinary partial differential equations which are solved either by means of continuation algorithm or via direct time integration. Specifically, the frequency response plots and amplitude curves, their stability and bifurcation are obtained using continuation algorithm. Numerical results reveal the rich and interesting nonlinear phenomena that have not been presented in the existent literature on the nonlinear dynamics of axially moving systems.

Combination, principal parametric and internal resonances of an accelerating beam under two frequency parametric excitation

In this paper, analytical and numerical approach is applied to find the steady-state and dynamic behaviors of an axially accelerating viscoelastic beam subject to two-frequency parametric excitation in presence of internal resonance. Direct method of multiple scales is employed to solve the cubic nonlinear integro-partial differential equation. As a result, the governing equation of motion is reduced to a set of nonlinear first-order partial differential equations. These equations are solved through continuation algorithm approach to find the frequency and amplitude response curves and their stability and bifurcation. The system reveals the presence of Hopf, saddle node, and pitchfork bifurcations. The dynamic bevavior of the system is estimated through phase portraits, time traces, Poincare maps, and FFT power spectra obtained via direct time integration. The evolution of maximum Lyapunov exponent reveals the system parameter where the dynamic response changes from stable periodic to unstable chaotic motion of the system.

Two-frequency parametric excitation and internal resonance of a moving viscoelastic beam

The present work accounts Timoshenko beam theory followed by Ritz approximation and an iterative technique to deal nonlinear free vibration problems of cracked Functionally Graded Material (FGM) be...

G. Pohit

Papers

A large deflection model for the pull-in analysis of electrostatically actuated microcantilever beams

Optimization of Performance and Emission Characteristics of Diesel Engine with Biodiesel Using Grey-Taguchi Method

Combination, principal parametric and internal resonances of an accelerating beam under two frequency parametric excitation

Two-frequency parametric excitation and internal resonance of a moving viscoelastic beam

Nonlinear modelling and dynamic analysis of cracked Timoshenko functionally graded beams based on neutral surface approach