Vibration and Sensitivity Analysis of a Beam With a Lumped Mass of Translational and Rotary Inertias

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
D. Wang
Keyword(s):  
Natural Frequency ◽  
Degrees Of Freedom ◽  
Free Vibration Analysis ◽  
Rotary Inertia ◽  
Closed Form Expression ◽  
Lumped Mass ◽  
Form Expression ◽  
Element Analysis ◽  
Discrete Method ◽  
The Finite Element Analysis

The free vibration analysis of a uniform beam carrying a lumped mass with the inclusion of both translational and rotary inertias are performed, and a closed-form expression of the frequency sensitivity with respect to the attachment location of the lumped mass is formulated using the discrete method upon the finite element analysis. By virtually introducing additional degrees of freedom at the mass-attached point, the first-order derivative of the natural frequency can be determined straightforwardly. Comparisons of numerical results from two typical examples show that the rotary inertia of a lumped mass may impose important effects on the natural frequency and its sensitivity. Neglecting the rotary inertia may lead to inaccurate or even erroneous solutions of the beam’s dynamics.

scholarly journals Investigation of Free Vibration Response of E-Glass/Epoxy Delaminated Composite Plates

2012 ◽  
Vol 21 (1) ◽  
pp. 096369351202100 ◽  
Author(s):  
Turan Ercopur ◽  
Binnur Goren Kiral
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Epoxy Composite ◽  
Free Vibration Analysis ◽  
Composite Plates ◽  
Vibration Response ◽  
Mode Shapes ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Free Vibration Response

This paper deals with the finite element analysis of free vibration response of the delaminated composite plates. Free vibration analysis is performed by using ANSYS commercial software developing parametric input files. Natural frequency values and associated mode shapes of E-glass/epoxy composite delaminated plates are determined. Effects of delamination shape, dimension and location on the natural frequency and associated mode shapes are investigated and for the purpose of the observing the effect of the boundary conditions, cantilever and clamped-pinned delaminated composite plates are taken into consideration. Comparisons with the results in literature verify the validity of the developed models in this study. It is observed that the natural frequency decreases in the existence of the delamination and level of the decrease depends on the dimension, shape and location of the delamination.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

Finite Element Analysis of 2-D Structures by New Strain Based Triangular Element

2018 ◽  
Vol 35 (3) ◽  
pp. 305-313 ◽  
Author(s):  
C. Rebiai
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Numerical Solutions ◽  
Time Integration ◽  
Triangular Element ◽  
Membrane Element ◽  
Lumped Mass ◽  
Element Analysis ◽  
Benchmark Tests ◽  
Three Degrees Of Freedom

ABSTRACTIn this investigation, a new simple triangular strain based membrane element with drilling rotation for 2-D structures analysis is proposed. This new numerical model can be used for linear and dynamic analysis. The triangular element is named SBTE and it has three nodes with three degrees of freedom at each node. The displacements field of this element is based on the assumed functions for the various strains satisfying the compatibility equations. This developed element passed both patch and benchmark tests in the case of bending and shear problems. For the dynamic analysis, lumped mass with implicit/explicit time integration are employed. The obtained numerical results using the developed element converge toward the analytical and numerical solutions in both analyses.

Free Vibration Analysis of PZT Glide Heads

1999 ◽  
Vol 121 (4) ◽  
pp. 984-988 ◽  
Author(s):  
Alex Y. Tsay ◽  
Jin-Hui Ouyang ◽  
C.-P. Roger Ku ◽  
I. Y. Shen ◽  
David Kuo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Laser Doppler Vibrometer ◽  
Free Vibration Analysis ◽  
Mode Shapes ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Bonding Length ◽  
Measured Displacement

This paper studies natural frequencies and mode shapes of a glide head with a piezoelectric transducer (PZT) through calibrated experiments and a finite element analysis. In the experiments, the PZT transducer served as an actuator exciting the glide head from 100 kHz to 1.3 MHz, and a laser Doppler vibrometer (LDV) measured displacement of the glide head at the inner or outer rail. The natural frequencies were measured through PZT impedance and frequency response functions from PZT to LDV. In the finite element analysis, the glide head was meshed by brick elements. The finite element results show that there are two types of vibration modes: slider modes and PZT modes. Only the slider modes are important to glide head applications. Moreover, natural frequencies predicted from the finite element analysis agree well with the experimental results within 5% of error. Finally, the finite element analysis identifies four critical slider dimensions whose tolerance will significantly vary the natural frequencies: PZT bonding length, wing thickness, slider thickness, and air bearing recess depth.

Vibration Characteristic Analysis of V-Shaped Electrothermal Microactuator

2012 ◽  
Vol 503 ◽  
pp. 118-121
Author(s):  
Zhen Lu Wang ◽  
Xue Jin Shen ◽  
Ling Zhou ◽  
Xiao Yang Chen
Keyword(s):  
Theoretical Calculation ◽  
Natural Frequency ◽  
Mechanical Model ◽  
Natural Frequencies ◽  
Maximum Error ◽  
Vibration Characteristic ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
The Finite Element Analysis

This paper is focused on the finite element analysis (FEA) and theoretical calculation of vibration characterization of V-shaped electrothermal microactuator. A vibration mechanical model about V-shaped electrothermal microactuator is presented. By having a comparison between FEA and theoretical calculation about natural frequencies of V-shaped electrothermal microactuator, the maximum error is within 0.19 %. This paper also analyzes the influences of microactuator geometric parameters on natural frequency. The length and thickness have larger effect on the natural frequency of the actuator, while the angle and width have less effect on the natural frequency.

Finite Element Quarter Vehicle Suspension Model under Periodic Bump and Sinusoidal Road Excitation

2018 ◽  
Vol 880 ◽  
pp. 163-170
Author(s):  
Ștefan Cristian Castravete ◽  
Gabriel Cătălin Marinescu ◽  
Nicolae Dumitru ◽  
Oana Victoria Oţăt
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Finite Model ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Car Suspension ◽  
The Finite Element Analysis ◽  
Road Excitation ◽  
Suspension Model

The paper studies the behavior of a quarter-car suspension model under periodic road excitation: sinusoidal and bump (trapezoidal shape) for a constant vehicle speed. A theoretical and a finite element model were developed. The theoretical model has two degrees of freedom and a modal and sinusoidal excitation was performed to compare with finite model analysis. The finite element analysis consists of three parts: preload, modal analysis and deterministic external excitation. The study consists of the analysis of forces, displacements and accelerations that are transmitted to the vehicle regarding their variation in time and frequency.

Workspace Comparison Between 3-PRR and 3-RPR Micro-Manipulator

2012 ◽  
Author(s):  
Yi Dong ◽  
Feng Gao ◽  
Yi Yue ◽  
Jin Feng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
The Other ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Structural Differences ◽  
Micro Manipulator

This paper presents two compliant micro-manipulators with different structures. One uses 3-PRR mechanism while the other one adopts 3-RPR mechanism. Both of the two micro-manipulators have two translational degrees of freedom (DOF) and one rotational DOF. But the properties, such as workspace, of the two micro-manipulators are not the same. In this paper, the workspaces are studied and compared. First, the structural differences are presented. Then, the stiffness derivations of the two micro-manipulators are given and the workspaces are calculated considering the properties of piezoelectric (PZT) actuators. Finally the finite element analysis and prototype experiments are performed to validate the obtained results.

Development of a Closed-Form Expression for the Assessment of the Integrity of Internally Corroded Pipelines

2018 ◽  
Author(s):  
M. Fahed ◽  
I. Barsoum
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Steel ◽  
Parametric Study ◽  
Mechanical Response ◽  
Closed Form Expression ◽  
Burst Pressure ◽  
Form Expression ◽  
Element Analysis ◽  
Internal Corrosion

Carbon steel pipelines are renowned for their long-term resistance to the hydrostatic pressure of the transported fluid. Nevertheless, failure of carbon steel pipes can be catastrophic if not predicted or mitigated properly. One of the most common failure causes in carbon steel pipelines is corrosion of the pipeline inner and outer surfaces. The corrosion on pipeline walls will eventually lead to severe loss of material to a point which will cause complete loss of pipeline integrity. The study will assess the burst pressure of predefined internal corrosion-defected carbon steel pipelines through finite element analysis. The mechanical response of the host carbon steel pipeline is empirically estimated. A set of corrosion defect geometrical sizes, such as depth width and length to be considered is carefully developed. Accordingly, a parametric study considering the developed set of defect geometrical parameters, as well as the mechanical response of the pipe material, is conducted. The parametric study is performed through finite element analysis to investigate the influence of the highlighted parameters to the overall burst pressure of the pipe. Based on the results from parametric study of corrosion-defected carbon steel pipelines, the Buckingham π-theorem modelling approach is used to derive an analytical closed-form expression to predict the burst pressure of defected pipes containing internal corrosion defects of an arbitrary size.

Design and Analysis of a Planar Piezo-Actuated Nanopositioner with Millimeter Scale Stroke

2016 ◽  
Vol 679 ◽  
pp. 143-148
Author(s):  
Hui Tang ◽  
Jian Gao ◽  
Xin Chen ◽  
Lan Yu Zhang ◽  
Zhao He Zeng
Keyword(s):  
Degrees Of Freedom ◽  
Cross Coupling ◽  
Optimal Designs ◽  
Fast Tool Servo ◽  
Precision Manufacturing ◽  
Element Analysis ◽  
Satisfactory Performance ◽  
The Finite Element Analysis ◽  
High Bandwidth ◽  
Promising Application

In recent years, Fast Tool Servo (FTS) mechanism in precision manufacturing equipment emerges as a promising application for the piezo-actuated flexible nanopositioner. A flexible nanopositioner with large stroke, high bandwidth, high precision and multi-Degrees-of-Freedom (multi-DOFs) is really desired for this application. In order to meet this requirement, a novel 2-DOF flexible nanopositioner consists of two pairs of differential lever displacement amplifiers (DLDA) is proposed in this paper first, also, kinetostatics modeling is conducted by using the Pseudo-Rigid Body (PRB) method. After a series of mechanism optimal designs, the performance of the designed nanopositioner is verified by using the Finite Element Analysis (FEA) method. A piezoelectric (PZT) actuator with 90 µm is selected in this simulation, the experimental results indicate that the mechanism workspace can achieve around 2.1×2.1 mm2, the bandwidth can reach up to around 136 Hz, while the cross-coupling is also kept with 1%. All the results consistently prove the proposed device possesses satisfactory performance for fulfilling the practical precision manufacturing tasks.

Research on Natural Frequency of MEMS Structure with Meander Suspensions by Mechanical Character Analysis

2014 ◽  
Vol 609-610 ◽  
pp. 1369-1374
Author(s):  
Yi Jun Li ◽  
Ming Zhu Sun ◽  
Xin Zhao
Keyword(s):  
Finite Element Analysis ◽  
Natural Frequency ◽  
Deformation Theory ◽  
Energy Harvester ◽  
Analysis Method ◽  
Elasticity Coefficient ◽  
Mechanic Analysis ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Micro Deformation

A new concept of using four meander suspensions as a constraint is proposed to construct planar spring-like energy harvester actuators with larger displacement. Meander suspensions with multi-folded beams having three vibrating directions. This paper introduce a new structure of “-type” to calculate modulus of elasticity of one meander suspensions. Based upon the micro deformation theory and the displacement superposition theory, the expression on the displacement for the movement end of the meander beams by outer forces and force moments are deduced. Since the energy harvester is geometric symmetry, elasticity coefficient and natural frequency of the energy harvester will be deduce by above given information. The finite-element analysis was used to model the performances and verified the above mentioned mechanic analysis method.

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