Detailed Investigation of Capacitive Micromachined Ultrasound Transducer Design Space for Optimal Operation

2011 ◽  
Author(s):  
Onursal Onen ◽  
Rasim Guldiken
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Material Selection ◽  
Optimal Operation ◽  
Design Guidelines ◽  
Ultrasound Transducers ◽  
Response Curves ◽  
Design Studies ◽  
Strong Function ◽  
Transducer Design

This paper presents our detailed design studies on capacitive micromachined ultrasound transducers (CMUTs) via finite element models developed in ANSYS 12. In this study, we will discuss our experimentally verified coupled field finite element simulations for operation frequency and bandwidth. The effects of device geometry, type of coupling media, material selection and properties are investigated for the frequency response, and bandwidth using an analytical approach. A commercial design of experiment software, Minitab is utilized for sample runs for obtaining response curves. The design principles for CMUTs are given in detail for effective and quick design. The design guidelines illustrate that, the frequency response is a strong function of transducer geometry, material selection and coupling media.

Nonlinear Finite Element-Based Path Following of Periodic Solutions

2011 ◽  
Author(s):  
Andrea Arena ◽  
Giovanni Formica ◽  
Walter Lacarbonara ◽  
Harry Dankowicz
Keyword(s):  
Finite Element ◽  
Vector Field ◽  
Frequency Response ◽  
Periodic Solutions ◽  
Parametric Resonance ◽  
Primary Resonance ◽  
Path Following ◽  
State Variables ◽  
Response Curves ◽  
Space Dependence

A computational framework is proposed to path follow the periodic solutions of nonlinear spatially continuous systems and more general coupled multiphysics problems represented by systems of partial differential equations with time-dependent excitations. The set of PDEs is cast in first order differential form (in time) u˙ = f(u,s,t;c) where u(s,t) is the vector collecting all state variables including the velocities/time rates, s is a space coordinate (here, one-dimensional systems are considered without lack of generality for the space dependence) and t denotes time. The vector field f depends, in general, not only on the classical state variables (such as positions and velocities) but also on the space gradients of the leading unknowns. The space gradients are introduced as part of the state variables. This is justified by the mathematical and computational requirements on the continuity in space up to the proper differential order of the space gradients associated with the unknown position vector field. The path following procedure employs, for the computation of the periodic solutions, only the evaluation of the vector field f. This part of the path following procedure within the proposed combined scheme was formerly implemented by Dankowicz and coworkers in a MATLAB software package called COCO. The here proposed procedure seeks to discretize the space dependence of the variables using finite elements based on Lagrangian polynomials which leads to a discrete form of the vector field f. A concurrent bifurcation analysis is carried out by calculating the eigenvalues of the monodromy matrix. A hinged-hinged nonlinear beam subject to a primary-resonance harmonic transverse load or to a parametric-resonance horizontal end displacement is considered as a case study. Some primary-resonance frequency-response curves are calculated along with their stability to assess the convergence of the discretization scheme. The frequency-response curves are shown to be in close agreement with those calculated by direct integration of the PDEs through the FE software called COMSOL Multiphysics. Besides primary-resonance direct forcing conditions, also parametric forcing causing the principal parametric resonance of the lowest two bending modes is considered through construction of the associated transition curves. The proposed approach integrates algorithms from the finite element and bifurcation domains thus enabling an accurate and effective unfolding of the bifurcation and post-bifurcation scenarios of nonautonomous PDEs with the underlying structures.

Dynamic Characteristics Analysis and Topology Optimization of Column Based on Finite Element Method

2013 ◽  
Vol 721 ◽  
pp. 541-544
Author(s):  
Jing Chen ◽  
Ze Long Yang ◽  
Xian Xuan Li
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Response Analysis ◽  
Response Curves ◽  
Element Analysis ◽  
Column Structure

Aiming to improve the dynamic and static characteristics of a type of machining center column, the finite element modal analysis and harmonic response analysis of the column are performed, and this paper analyzes the dynamic characteristics of the column based on the first five mode shapes and natural frequencies of the column and the displacement - frequency response curves of the column. Topology optimization analysis of the column is performed with ANSYS, and the finite element analysis is performed on the column again after the column structure is improved based on the optimal distribution of material of the column structure and the design experience of column. The result shows that the first five natural frequencies of the column increase, the peak of the displacement - frequency response of the column decrease, and the dynamic characteristics are improved significantly.

COUPLED FINITE ELEMENT ANALYSIS OF A PIEZO-CERAMIC FORCE TRANSDUCER

2006 ◽  
Vol 30 (1) ◽  
pp. 167-181
Author(s):  
Behrouz Shiari ◽  
Peter M. Wild
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Frequency Response ◽  
Element Model ◽  
Force Transducer ◽  
Sensing Element ◽  
Element Analysis ◽  
Transducer Design ◽  
Flat Frequency Response ◽  
Good Agreement

The coupled finite element method is used to design a novel miniaturized piezoelectric force transducer for the pulp refiners. The analysis focuses on a proposed transducer design using commercially available piezoelectric sensing element and a steel assembled housing. The software ANSYS was used to create a finite element model in order to improve transducer electromechanical behaviour. The primary goal of modeling is to design a transducer with a frequency response higher than a lab-scale refiner. Thus, modal and harmonic responses of the transducer model are studied. A coupled electromechanical model is used for prediction the output of the transducer. In order to enhance the performance of the transducer, the design is studied with respect to output magnitude and a flat frequency response. The modeling results are used for fabrication a prototype force transducer. The experimental results showed good agreement with the modeling.

scholarly journals Investigating inlay designs of class II cavity with deep margin elevation using finite element method

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yung-Chung Chen ◽  
Chi-Lun Lin ◽  
Chun-Hsien Hou
Keyword(s):  
Finite Element ◽  
Stress Responses ◽  
Mechanical Performance ◽  
Material Selection ◽  
Design Guidelines ◽  
Geometric Design ◽  
Design Parameters ◽  
Element Analysis ◽  
Tooth Structure ◽  
Deep Margin

Abstract Background This study evaluates the mechanical performance of deep margin elevation technique for carious cavities by considering the shape designs and material selections of inlay using a computational approach combined with the design of experiments method. The goal is to understand the effects of the design parameters on the deep margin elevation technique and provide design guidelines from the biomechanics perspective. Methods Seven geometric design parameters for defining an inlay’s shape of a premolar were specified, and the influence of cavity shape and material selection on the overall stress distribution was investigated via automated modelling. Material selection included composite resin, ceramic, and lithium disilicate. Finite element analysis was performed to evaluate the mechanical behavior of the tooth and inlay under a compressive load. Next, the analysis of variance was conducted to identify the parameters with a significant effect on the stress occurred in the materials. Finally, the response surface method was used to analyze the stress responses of the restored tooth with different design parameters. Results The restored tooth with a larger isthmus width demonstrated superior mechanical performance in all three types of inlay materials, while the influence of other design parameters varied with the inlay material selection. The height of the deep margin elevation layer insignificantly affected the mechanical performance of the restored tooth. Conclusions A proper geometric design of inlay enhances the mechanical performance of the restored tooth and could require less volume of the natural dentin to be excavated. Furthermore, under the loading conditions evaluated in this study, the deep margin elevation layer did not extensively affect the strength of the tooth structure.

Effects of nonlinear interactions of flexural modes on the performance of a beam autoparametric vibration absorber

2019 ◽  
Vol 26 (7-8) ◽  
pp. 459-474
Author(s):  
Saeed Mahmoudkhani ◽  
Hodjat Soleymani Meymand
Keyword(s):  
Frequency Response ◽  
Internal Resonance ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Primary System ◽  
Lumped Mass ◽  
Response Curves ◽  
Internal Resonances ◽  
The One

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

scholarly journals Development of Simulation Based p-Multipliers for Laterally Loaded Pile Groups in Granular Soil Using 3D Nonlinear Finite Element Model

2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Muhammad Bilal Adeel ◽  
Muhammad Asad Jan ◽  
Muhammad Aaqib ◽  
Duhee Park
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Design Guidelines ◽  
American Petroleum Institute ◽  
Winkler Foundation ◽  
Group Effect ◽  
Pile Groups ◽  
Element Analysis ◽  
Laterally Loaded Pile ◽  
Laterally Loaded

The behavior of laterally loaded pile groups is usually accessed by beam-on-nonlinear-Winkler-foundation (BNWF) approach employing various forms of empirically derived p-y curves and p-multipliers. Averaged p-multiplier for a particular pile group is termed as the group effect parameter. In practice, the p-y curve presented by the American Petroleum Institute (API) is most often utilized for piles in granular soils, although its shortcomings are recognized. In this study, we performed 3D finite element analysis to develop p-multipliers and group effect parameters for 3 × 3 to 5 × 5 vertically squared pile groups. The effect of the ratio of spacing to pile diameter (S/D), number of group piles, varying friction angle (φ), and pile fixity conditions on p-multipliers and group effect parameters are evaluated and quantified. Based on the simulation outcomes, a new functional form to calculate p-multipliers is proposed for pile groups. Extensive comparisons with the experimental measurements reveal that the calculated p-multipliers and group effect parameters are within the recorded range. Comparisons with two design guidelines which do not account for the pile fixity condition demonstrate that they overestimate the p-multipliers for fixed-head condition.

Study of material selection and design improvement for a portable blender by using finite element analysis

2021 ◽  
Author(s):  
R. M. Farizuan ◽  
A. R. Irfan ◽  
H. Radhwan ◽  
Shafeeq Ahmad Shamim Ahmad ◽  
Khoo Kin Fai ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Selection ◽  
Element Analysis ◽  
Design Improvement

Study of plate vibrating in fluids having part-through crack at random angles and locations

2021 ◽  
pp. 095440622110127
Author(s):  
Ruqia Ikram ◽  
Asif Israr
Keyword(s):  
Frequency Response ◽  
Multiple Scales ◽  
Peak Amplitude ◽  
Nonlinear Frequency ◽  
Response Curves ◽  
Crack Location ◽  
Cracked Plate ◽  
Nonlinear Frequency Response ◽  
Angle Crack ◽  
Crack Angle

This study presents the vibration characteristics of plate with part-through crack at random angles and locations in fluid. An experimental setup was designed and a series of tests were performed for plates submerged in fluid having cracks at selected angles and locations. However, it was not possible to study these characteristics for all possible crack angles and crack locations throughout the plate dimensions at any fluid level. Therefore, an analytical study is also carried out for plate having horizontal cracks submerged in fluid by adding the influence of crack angle and crack location. The effect of crack angle is incorporated into plate equation by adding bending and twisting moments, and in-plane forces that are applied due to antisymmetric loading, while the influence of crack location is also added in terms of compliance coefficients. Galerkin’s method is applied to get time dependent modal coordinate system. The method of multiple scales is used to find the frequency response and peak amplitude of submerged cracked plate. The analytical model is validated from literature for the horizontally cracked plate submerged in fluid as according to the best of the authors’ knowledge, literature lacks in results for plate with crack at random angle and location in the presence of fluid following validation with experimental results. The combined effect of crack angle, crack location and fluid on the natural frequencies and peak amplitude are investigated in detail. Phenomenon of bending hardening or softening is also observed for different boundary conditions using nonlinear frequency response curves.

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