Romesh C. Batra

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We study the influence of von Karman nonlinearity, van der Waals force, and a athermal stresses on pull-in instability and small vibrations of electrostatically actuated mi-croplates. We use the Galerkin method to develop a tractable reduced-order model for elec-trostatically actuated clamped rectangular microplates in the presence of van der Waals(More)
We analyze electrostatic deformations of rectangular, annular circular, solid circular, and elliptic micro-electromechanical systems (MEMS) by modeling them as elastic membranes. The nonlinear Poisson equation governing their deformations is solved numerically by the meshless local Petrov–Galerkin (MLPG) method. A local symmetric augmented weak formulation(More)
We describe the development of modules for teaching a senior level course, Mechanical Behavior of Materials, that incorporate the results of state of the art simulation techniques. The modules are Web-Java based and make extensive use of materials available through the Internet. The most important characteristic of these modules is that they teach the(More)
An analytical solution is presented for three-dimensional thermomechanical deformations of a simply supported functionally graded (FG) rectangular plate subjected to time-dependent thermal loads on its top and/or bottom surfaces. Material properties are taken to be analytical functions of the thickness coordinate. The uncoupled quasi-static linear(More)
A robust nonlinear observer, utilizing the sliding mode concept, is developed for the dynamic positioning of ships. The observer provides the estimates of linear velocities of the ship and bias from the slowly varying environmental loads. It also filters out wave frequency motion to avoid wear of actuators and excessive fuel consumption. Especially, the(More)
The problem of calculating the overall elastic moduli of a microcracked material is now understood relatively well, however, only under the assumption that the cracks are fixed, that is, neither grow nor shorten during loading. Such a calculation yields the secant moduli for the response stress-strain curves of microcracked materials. The present paper(More)
Three-dimensional deformations of a multilayered, linear elastic, anisotropic rectangular plate subjected to arbitrary boundary conditions at its edges are analyzed by the generalized Eshelby-Stroh formalism. The rectangular laminate consists of anisotropic and homogeneous laminae of arbitrary thicknesses. Perfect bonding is assumed between the adjoining(More)
Values of constants c 2 and c 3 in Table 1 should be interchanged (i.e., c 2 = 0.126 and c 3 = 0.325. Authors apologize for any inconvenience caused to users of the Table. Abstract: A novel estimate for the line-to-ground capacitance that accurately predicts the pull-in instability parameters for narrow electrostatically actuated microbeams is proposed.(More)
We consider the von Kármán nonlinearity and the Casimir force to develop reduced-order models for prestressed clamped rectangular and circular electrostatically actuated microplates. Reduced-order models are derived by taking flex-ural vibration mode shapes as basis functions for the transverse displacement. The in-plane displacement vector is decomposed as(More)