Browsing by Author "Simha, A."

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A Simple Displacement Function to Determine the Response of a Micro Capacitive Pressure Sensor
(2011) Simha, A.; Kulkarni, S.M.; Meenatchi Sundaram, S.; Bhat, S.
The response of a capacitive pressure sensor is generally represented by a fourth order partial differential equation which is complex to solve and does not possess an exact solution. Several attempts have been made earlier through various techniques such as the Galerkin method, Finite Difference Method etc.... In this paper an attempt has been made to develop a simple approximate analytical approach to determine the response of a micro capacitive pressure sensor whose diaphragm is designed to undergo very small deflections (typically less than 25% of the thickness). The non-uniform gap between the electrodes is mathematically expressed as a combination of the initial gap between the electrodes (in the undeformed state) and a displacement function in (x,y). The proposed displacement function is then utilized in evaluating the capacitance as a function of the applied pressure. The results obtained from the analytical approach are benchmarked against those obtained from COMSOL MultiphysicsÂ®, a popular Finite Element Analysis tool in the MEMS industry. It is observed that the results obtained from COMSOL MultiphysicsÂ® and those from the analytical approach are in good agreement with a maximum deviation of about 8.66%. Â© 2011 American Institute of Physics.
An analytical method to determine the response of a micro capacitive pressure sensor
(2011) Simha, A.; Kulkarni, S.M.; Meenatchi Sundaram, S.
The response of a capacitive pressure sensor is generally represented by a fourth order partial differential equation which is complex to solve and does not possess an exact solution. Several attempts have been made earlier through various techniques such as the Galerkin method, Finite Difference Method etc. In this paper an attempt has been made to develop a simple approximate analytical approach to determine the response of a capacitive pressure sensor whose diaphragm is designed to undergo very small deflections (typically less than 25 % of the thickness). The nonuniform gap between the electrodes is mathematically expressed as a combination of the initial gap between the electrodes (in the undeformed state) and a displacement function in (x, y). The proposed displacement function is then utilized in evaluating the capacitance as a function of the applied pressure. The results obtained from the analytical approach are benchmarked against those obtained from COMSOL Multiphysics®, a popular Finite Element Analysis tool in the MEMS industry. It is observed that the results obtained from COMSOL Multiphysics® and those from the analytical approach are in good agreement with a maximum deviation of about 3.38 %. © 2011 IFSA.
Lumped parameter modeling of absolute and differential micro pressure sensors
(2012) Meenatchi Sundaram, S.; Simha, A.; Menon, M.K.; Kulkarni, S.M.; Bhat, S.
Mechanical systems may be modeled as systems of lumped masses (rigid bodies) or as distributed mass (continuous) systems. The latter are modeled by partial differential equations, whereas the former are represented by ordinary differential equations [1] In this paper a lumped parameter model of absolute and differential pressure sensors are developed, whose diaphragm is designed to undergo very small deflections (typically less than 25% of the thickness). A simple approximate model with proper assumptions are considered and analyzed first. A more appropriate model with refined approximation is considered later. Estimation of various parameters like mass, spring constant and damping of the diaphragm & fluid are done and used to estimate the transfer function. The transfer function is then used to understand the frequency and stability analysis of the system. A square, rigidly fixed diaphragm pressure sensor is considered in this work. By limiting the maximum deflection to one-fourth of the thickness, the analysis has been done for a maximum applied pressure of 100 MPa. MATLAB® is used as a tool to carry out the analysis. © 2012 IFSA.
A Simple Displacement Function to Determine the Response of a Micro Capacitive Pressure Sensor
(2011) Simha, A.; Kulkarni, S.M.; Meenatchisundaram, S.; Bhat, S.
The response of a capacitive pressure sensor is generally represented by a fourth order partial differential equation which is complex to solve and does not possess an exact solution. Several attempts have been made earlier through various techniques such as the Galerkin method, Finite Difference Method etc.... In this paper an attempt has been made to develop a simple approximate analytical approach to determine the response of a micro capacitive pressure sensor whose diaphragm is designed to undergo very small deflections (typically less than 25% of the thickness). The non-uniform gap between the electrodes is mathematically expressed as a combination of the initial gap between the electrodes (in the undeformed state) and a displacement function in (x,y). The proposed displacement function is then utilized in evaluating the capacitance as a function of the applied pressure. The results obtained from the analytical approach are benchmarked against those obtained from COMSOL Multiphysics�, a popular Finite Element Analysis tool in the MEMS industry. It is observed that the results obtained from COMSOL Multiphysics� and those from the analytical approach are in good agreement with a maximum deviation of about 8.66%. � 2011 American Institute of Physics.