Silicon micromachining technology for sub-nanogram discrete mass resonant biosensors

1992 ◽  
Vol 70 (10-11) ◽  
pp. 1178-1183 ◽  
Author(s):  
S. Prescesky ◽  
M. Parameswaran ◽  
A. Rawicz ◽  
R. F. B. Turner ◽  
U. Reichl
Keyword(s):  
Silicon Dioxide ◽  
First Generation ◽  
Mode Shapes ◽  
Sensing Element ◽  
Small Vibration ◽  
Element Analysis ◽  
Resonant Amplitude ◽  
Beam Incident ◽  
Discrete Mass ◽  
Angular Shift

This paper describes a novel sub-nanogram discrete mass sensor with possible biological applications including potential biomass monitoring of living cells in culture. The sensing element is a micromachined silicon dioxide cantilever fabricated using a process compatible with commercial CMOS microelectronic processes. The 1 μm thick silicon dioxide device consists of two 8 × 150 μm cantilever arms supporting a 50 × 50 μm payload platform. Actuation of this first generation device is performed using a small vibration table. Resonant amplitude are measured by detecting the angular shift of a laser beam incident on the device. Finite element analysis is used to model resonant frequencies, mode shapes, and frequency response. Cantilever resonates in fundamental mode at 15.9 kHz and have an experimental mass sensitivity of 1.9 kHz ng−1.

Rotor-Dynamics of Different Shaft Configurations for a 6 kW Micro Gas Turbine for Concentrated Solar Power

2016 ◽  
Author(s):  
A. Arroyo ◽  
M. McLorn ◽  
M. Fabian ◽  
M. White ◽  
A. I. Sayma
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Dynamic Models ◽  
Solar Power ◽  
Critical Issue ◽  
Rotor Dynamics ◽  
Mode Shapes ◽  
Concentrated Solar Power ◽  
Element Analysis ◽  
Rotor Dynamic

Rotor-dynamics of Micro Gas Turbines (MGTs) under 30 kW have been a critical issue for the successful development of reliable engines during the last decades. Especially, no consensus has been reached on a reliable MGT arrangement under 10 kW with rotational speeds above 100,000 rpm, making the understanding of the rotor-dynamics of these high speed systems an important research area. This paper presents a linear rotor-dynamic analysis and comparison of three mechanical arrangements of a 6 kW MGT intended for utilising Concentrated Solar Power (CSP) using a parabolic dish concentrator. This application differs from the usual fuel burning MGT in that it is required to operate at a wider operating speed range. The objective is to find an arrangement that allows reliable mechanical operation through better understanding of the rotor dynamics for a number of alternative shaft-bearings arrangements. Finite Element Analysis (FEA) was used to produce Campbell diagrams and to determine the critical speeds and mode shapes. Experimental hammer tests using a new approach based on optical sensing technology were used to validate the rotor-dynamic models. The FEA simulation results for the natural frequencies of a shaft arrangement were within 5% of the measurements, while the deviation for the shaft-bearings arrangement increased up to 16%.

scholarly journals Rapid Evaluation for Position-Dependent Dynamics of a 3-DOF PKM Module

2014 ◽  
Vol 6 ◽  
pp. 238928 ◽  
Author(s):  
Hai-wei Luo ◽  
Hui Wang ◽  
Jun Zhang ◽  
Qi Li
Keyword(s):  
Natural Frequencies ◽  
Mode Shapes ◽  
Parallel Kinematic Machine ◽  
Computationally Efficient ◽  
Element Analysis ◽  
Reduction Techniques ◽  
Modal Reduction ◽  
Governing Differential Equation ◽  
Parallel Kinematic ◽  
Analytical System

Based on the substructure synthesis and modal reduction technique, a computationally efficient elastodynamic model for a fully flexible 3-RPS parallel kinematic machine (PKM) tool is proposed, in which the frequency response function (FRF) at the end of the tool can be obtained at any given position throughout its workspace. In the proposed elastodynamic model, the whole system is divided into a moving platform subsystem and three identical RPS limb subsystems, in which all joint compliances are included. The spherical joint and the revolute joint are treated as lumped virtual springs with equal stiffness; the platform is treated as a rigid body and the RPS limbs are modelled with modal reduction techniques. With the compatibility conditions at interfaces between the limbs and the platform, an analytical system governing differential equation is derived. Based on the derived model, the position-dependent dynamic characteristics such as natural frequencies, mode shapes, and FRFs of the 3-RPS PKM are simulated. The simulation results indicate that the distributions of natural frequencies throughout the workspace are strongly dependant on mechanism's configurations and demonstrate an axial-symmetric tendency. The following finite element analysis and modal tests both validate the analytical results of natural frequencies, mode shapes, and the FRFs.

scholarly journals Finite Element Analysis of Damping Properties of High Strength Aluminum A356 Alloy Composite

2019 ◽  
Vol 8 (12S2) ◽  
pp. 298-300
Keyword(s):  
Silicon Content ◽  
A356 Alloy ◽  
High Strength ◽  
Mode Shapes ◽  
Damping Properties ◽  
High Quality ◽  
Element Analysis ◽  
Present Evaluation ◽  
Aluminum A356 Alloy ◽  
Numerical Examination

Aluminum composites are in reality notably used as a piece of various programs due to their tremendous load to quality homes. Many studies works had been finished to ponder and improve the mechanical houses of aluminum mixes. The formation of alloying segments anticipate a fundamental component in choosing the properties of a mix. The eventual results of numerical systems have been recognized via and massive as they eagerly facilitate with the check comes to fruition. In the present evaluation a numerical examination contraption i.E., restrained section examination (FEA) is used. The paintings presented in this paper is away for the examination of effect of vibration traits of aluminum blends of various sport plans. The displaying and evaluation is finished the usage of ANSYS programming. A secluded assessment is carried out to recognize the vibration direct i.E., trademark repeat and mode shapes, of the cloth considered. The mode shapes and fashionable Recurrence receive a essential part within the framework Of dynamic machines. The consonant evaluation has been made to choose repeat traits. The examination software scrutinizes the information from the records archive shapes the information and makes the yield document containing the nodal migrations and nodal stretch estimations of various nerves. From the examination it's miles assumed that as the copper and silicon content material within the amalgams grows winding decreases then again. ANSYS comes about insist the smallest Modulus twisting and a definitive tractable strengthincaseofthe380 mixes of 380 additions with the extension in copper and silicon content. Subsequently Al 380 amalgams show high-quality fine with least vibration.

scholarly journals NASTRAN Analysis of a Turbine Blade and Comparison With Test and Field Data

1975 ◽  
Author(s):  
J. M. Allen ◽  
L. B. Erickson
Keyword(s):  
Turbine Blade ◽  
Natural Frequencies ◽  
Beam Theory ◽  
Mode Shapes ◽  
Stress Distributions ◽  
Free Standing ◽  
Element Analysis ◽  
Metallographic Examination ◽  
Stiffening Effect ◽  
Generalized Beam Theory

A NASTRAN finite element analysis of a free standing gas turbine blade is presented. The analysis entails calculation of the first four natural frequencies, mode shapes, and relative vibratory stresses, as well as deflections and stresses due to centrifugal loading. The stiffening effect of the centrifugal force field was accounted for by using NASTRAN’s differential stiffness option. Natural frequencies measured in a rotating test correlated well with computed results. Areas of maximum vibratory stress (fundamental mode) coincided with the three zones of crack initiation observed in a metallographic examination of a fatigue failure. Airfoil stress distributions were found to be significantly different from that predicted by generalized beam theory, especially near the airfoil-platform junction.

scholarly journals Elastic soil

1971 ◽  
Vol 4 (2) ◽  
pp. 258-269
Author(s):  
A. J. Carr ◽  
P. J. Moss
Keyword(s):  
Plane Strain ◽  
Plane Stress ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Mode Shapes ◽  
Element Analysis ◽  
Structure Interaction ◽  
Stiffness Properties ◽  
Acceleration History ◽  
Elastic Soil

This paper presents a refined finite element analysis for the analysis of two-dimensional plane stress and plane strain structures with particular emphasis being placed on the ability to solve problems of soil-structure interaction under earthquake loadings. The structure and
the soil are idealized as an assemblage of quadrilateral plane stress and plane strain elements having a cubic variation in displacement enabling a more accurate representation of the stiffness properties of the system than that previously available. The response of the system to the earthquake acceleration history is achieved by a superposition of normal mode responses and the methods of obtaining the mode shapes and frequencies are outlined. Examples are presented to illustrate the capability of this approach.

Design and Analysis of Foldable Vehicle using Finite Element Simulation

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Vikas Radhakrishna Deulgaonkar ◽  
S.N. Belsare ◽  
Naik Shreyas ◽  
Dixit Pratik ◽  
Kulkarni Pranav ◽  
...  
Keyword(s):  
Finite Element ◽  
Dynamic Properties ◽  
Mode Shapes ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Dynamic Stresses ◽  
Element Simulation ◽  
Vehicle Structure ◽  
Similar Materials ◽  
Good Agreement

Present work deals with evaluation of stress, deflection and dynamic properties of the folded vehicle structure. The folded vehicle in present case is a single seat vehicle intended to carry one person. Design constraints are the folded dimensions of the vehicle and the maximum vehicle speed is limited to 15m/s. Using classical calculations dimensions of the vehicle are devised. Different materials are used for seat, telescopic support and chassis of the foldable vehicle. computer aided model is prepared using CATIA software. Finite element analysis of the foldable vehicle has been carried out to evaluate the static and dynamic stresses induced in the vehicle components. Meshing of the foldable vehicle is carried using Ansys Workbench. From modal analysis six mode shapes of the foldable vehicle are formulated, corresponding frequencies and deflections are devised. Mesh generator is used to mesh the foldable vehicle. The deflection and frequency magnitudes of foldable vehicle evaluated are in good agreement with the experimental results available in literature for similar materials.

Updating of Non-Conservative Systems Using Inverse Methods

1997 ◽  
Author(s):  
Ladislav Starek ◽  
Milos Musil ◽  
Daniel J. Inman
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Natural Frequencies ◽  
Eigenvalue Problems ◽  
Model Updating ◽  
Analytical Models ◽  
Mode Shapes ◽  
Element Analysis ◽  
Modal Data

Abstract Several incompatibilities exist between analytical models and experimentally obtained data for many systems. In particular finite element analysis (FEA) modeling often produces analytical modal data that does not agree with measured modal data from experimental modal analysis (EMA). These two methods account for the majority of activity in vibration modeling used in industry. The existence of these discrepancies has spanned the discipline of model updating as summarized in the review articles by Inman (1990), Imregun (1991), and Friswell (1995). In this situation the analytical model is characterized by a large number of degrees of freedom (and hence modes), ad hoc damping mechanisms and real eigenvectors (mode shapes). The FEM model produces a mass, damping and stiffness matrix which is numerically solved for modal data consisting of natural frequencies, mode shapes and damping ratios. Common practice is to compare this analytically generated modal data with natural frequencies, mode shapes and damping ratios obtained from EMA. The EMA data is characterized by a small number of modes, incomplete and complex mode shapes and non proportional damping. It is very common in practice for this experimentally obtained modal data to be in minor disagreement with the analytically derived modal data. The point of view taken is that the analytical model is in error and must be refined or corrected based on experimented data. The approach proposed here is to use the results of inverse eigenvalue problems to develop methods for model updating for damped systems. The inverse problem has been addressed by Lancaster and Maroulas (1987), Starek and Inman (1992,1993,1994,1997) and is summarized for undamped systems in the text by Gladwell (1986). There are many sophisticated model updating methods available. The purpose of this paper is to introduce using inverse eigenvalues calculated as a possible approach to solving the model updating problem. The approach is new and as such many of the practical and important issues of noise, incomplete data, etc. are not yet resolved. Hence, the method introduced here is only useful for low order lumped parameter models of the type used for machines rather than structures. In particular, it will be assumed that the entries and geometry of the lumped components is also known.

Design for Desired Mode Shapes: Preliminary Results

1998 ◽  
Author(s):  
Elizabeth K. Lai ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Feasibility Study ◽  
Mode Shape ◽  
Longitudinal Axis ◽  
Mode Shapes ◽  
Future Research ◽  
Structural Members ◽  
Element Analysis ◽  
Cross Sectional ◽  
Made In

Abstract This paper is concerned with the shape optimization of structures to attain prescribed normal mode shapes. Optimizing structural members in order to have desired mode shapes, besides the desired natural frequencies, is of interest in some applications at both macro and micro scales. After reviewing the relevant past work on the “inverse mode shape” problem, a feasibility study using the lumped spring-mass models and finite element models of an axially vibrating bar is presented. Based on the observations made in the feasibility study with bars, a meaningful optimization problem is formulated and solved. Using finite element analysis and numerical optimization, a method for designing beam-like structures for prescribed mode shapes is developed. The method is demonstrated with an example of designing the cross-sectional area profile of a beam along its longitudinal axis to get a desired fundamental mode shape. The nonuniqueness of the solution is noted and avenues for future research are identified.

scholarly journals Experimental and Numerical Investigation of Resonance Characteristics of Novel Pumping Element Driven by Two Piezoelectric Bimorphs

2019 ◽  
Vol 9 (6) ◽  
pp. 1234 ◽  
Author(s):  
Yu-Chih Lin ◽  
Yu-Hsi Huang ◽  
Kwen-Wei Chu
Keyword(s):  
Speckle Pattern ◽  
Laser Doppler Vibrometer ◽  
Impedance Analysis ◽  
Vibration Characteristics ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Element Analysis ◽  
Visible Displacement ◽  
Piezoelectric Bimorphs ◽  
Phase Motion

This paper describes the vibration characteristics of a dual-bimorph piezoelectric pumping element under fluid–structure coupling. Unlike the single bimorph used in most previous studies, the proposed device comprises two piezoelectric bimorphs within an acrylic housing. Amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) was used to examine the visible displacement fringes in order to elucidate the anti-phase as well as in-phase motions associated with vibration. Analysis was also conducted using impedance analysis and laser Doppler vibrometer (LDV) based on the measurement of point-wise displacement. The experimental results of resonant frequencies and the corresponding mode shapes are in good agreement with those obtained using finite element analysis. The gain of flow rate obtained by the anti-phase motion of the dual-bimorph pumping element is larger than both those obtained by in-phase motion and the single bimorph pumping element. This work greatly enhances our understanding of the vibration characteristics of piezoelectric pumping elements with two bimorphs, and provides a valuable reference for the further development of bionic pump designs.

Investigation of stiffness of small wind turbine blade based on vibration analysis technique

2019 ◽  
Vol 44 (1) ◽  
pp. 49-59
Author(s):  
Nilesh Chandgude ◽  
Nitin Gadhave ◽  
Ganesh Taware ◽  
Nitin Patil
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Wind Turbine ◽  
Natural Frequency ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Element Analysis ◽  
Finite Element Software ◽  
Small Wind Turbine

In this article, three small wind turbine blades of different materials were manufactured. Finite element analysis was carried out using finite element software ANSYS 14.5 on modeled blades of National Advisory Committee for Aeronautics 4412 airfoil profile. From finite element analysis, first, two flap-wise natural frequencies and mode shapes of three different blades are obtained. Experimental vibration analysis of manufactured blades was carried out using fast Fourier transform analyzer to find the first two flap-wise natural frequencies. Finally, the results obtained from the finite element analysis and experimental test of three blades are compared. Based on vibration analysis, we found that the natural frequency of glass fiber reinforced plastic blade reinforced with aluminum sheet metal (small) strips increases compared with the remaining blades. An increase in the natural frequency indicates an increase in the stiffness of blade.

Sign in / Sign up

Export Citation Format

Share Document