Optimal locally resonant bandgaps in a windmill-like phononic crystal structure

2021 ◽  
pp. 2150264
Author(s):  
Xingfu Ma ◽  
Hang Xiang ◽  
Xiane Yang ◽  
Jiawei Xiang
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Finite Element ◽  
Response Surface Methodology ◽  
Phononic Crystal ◽  
Optimization Method ◽  
Key Factors ◽  
Optimal Range ◽  
Simulation Data

In this paper, a windmill-like phononic crystal (PC) structure with optimal locally resonant bandgaps (LRBGs) is proposed. By analyzing the variation trend of BGs, three geometric parameters (the side length and height of cuboid scatterer, and the width of elastic beams) are found to be key factors for the determination of BGs. Using response surface methodology (RSM), 3-factor and 7-level experiment are designed to obtain experimental data with the help of finite element simulations. Three relationships (fitting equations) between the three factors and the second BGs terminating frequency, the first BGs bandwidth, and the second BGs bandwidth, are further obtained by fitting the simulation data. Based on the three fitting equations, the optimal LRBGs are finally obtained using a simple optimization method. The proposed windmill-like structure PC is demonstrated to possess an optimal range of BG.

Theoretical determination of the structures of CaSiO3 perovskites

2006 ◽  
Vol 62 (6) ◽  
pp. 1025-1030 ◽  
Author(s):  
Razvan Caracas ◽  
Renata M. Wentzcovitch
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Determination ◽  
Functional Theory ◽  
Starting Point ◽  
Atomic Coordinates ◽  
The Ideal

Density functional theory is used to determine the possible crystal structure of the CaSiO3 perovskites and their evolution under pressure. The ideal cubic perovskite is considered as a starting point for studying several possible lower-symmetry distorted structures. The theoretical lattice parameters and the atomic coordinates for all the structures are determined, and the results are discussed with respect to experimental data.

scholarly journals A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

2021 ◽  
Author(s):  
Wassim Habchi ◽  
Philippe Vergne
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Film Thickness ◽  
Quantitative Determination ◽  
Excellent Agreement ◽  
Operating Conditions ◽  
Pure Rolling ◽  
Minimum Film Thickness

Abstract The current work presents a quantitative approach for the prediction of minimum film thickness in elastohydrodynamic lubricated (EHL) circular contacts. In contrast to central film thickness, minimum film thickness can be hard to accurately measure, and it is usually poorly estimated by classical analytical film thickness formulae. For this, an advanced finite-element-based numerical model is used to quantify variations of the central-to-minimum film thickness ratio with operating conditions, under isothermal Newtonian pure-rolling conditions. An ensuing analytical expression is then derived and compared to classical film thickness formulae and to more recent similar expressions. The comparisons confirmed the inability of the former to predict the minimum film thickness, and the limitations of the latter, which tend to overestimate the ratio of central-to-minimum film thickness. The proposed approach is validated against numerical results as well as experimental data from the literature, revealing an excellent agreement with both. This framework can be used to predict minimum film thickness in circular elastohydrodynamic contacts from knowledge of central film thickness, which can be either accurately measured or rather well estimated using classical film thickness formulae.

Development of Material Constants for Nonlinear Finite-Element Analysis

1988 ◽  
Vol 61 (5) ◽  
pp. 879-891 ◽  
Author(s):  
Robert H. Finney ◽  
Alok Kumar
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Large Strain ◽  
Strain Range ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Material Models ◽  
Tensile Data

Abstract The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.

scholarly journals Structure Determination of Ho2PdSi3

2014 ◽  
Vol 70 (a1) ◽  
pp. C224-C224
Author(s):  
Melanie Nentwich ◽  
Matthias Zschornak ◽  
Carsten Richter ◽  
Dmitri Novikov ◽  
Dirk Meyer
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Local Environment ◽  
Ray Method ◽  
X Ray ◽  
Metal Silicides ◽  
Wide Range ◽  
Site Selective ◽  
Palladium Silicide

Holmium-Palladium-Silicide Ho2PdSi3 is a member of rare earth-transition metal silicides exhibiting a wide range of interesting magnetic and electrical properties like multiple transition temperatues. The crystal structure results from HoSi2 by substitution of Si by Pd which is ordering commensurably with a 2 × 2 × 8 superstructure confirmed by a previous XRD and a Diffraction Anomalous Fine Structure (DAFS) measurement of the super structure reflection 1/2 1/2 3/8. DAFS is a X-ray method combining the advantages of absorption and diffraction and hence offers the possibility of element and site selective studies. Thus, it was feasible to probe the local environment of Ho and Pd separately. In the following, we will present a comparison of several structure proposals of Ho2PdSi3 with experimental data from beamline E2 and BW1 of the former synchrotron DORIS III at DESY/HASYLAB.

Stiffness Simulation Analysis of Rubber Bush Mountings Subjected to Tilting Deflection

2013 ◽  
Vol 765-767 ◽  
pp. 341-344
Author(s):  
Bai Qin ◽  
Chao Wu ◽  
Bo Zhang ◽  
Quan Fu Wang ◽  
Ya Juan Ji
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Simulation Model ◽  
Axial Length ◽  
Simulation Analysis ◽  
Element Model ◽  
Simulation Data ◽  
Model Based ◽  
The Finite Element Model

The finite element model of rubber bush mountings is built up. And the value of the reduced tilting stiffness is obtained directly by solving the model. The simulation data and the experimental data can be seen to agree very closely. This fully proves the reliability of the simulation model. Based on this simulation model, which has been parameterized, the influence of the axial length and inner and outer radii on the reduced tilting stiffness of rubber bush is studied by using the co-simulation of MATLAB and ANSYS.

Determination of Surface Acoustic Admittances by Inverse Solution of Finite Element Modeling in the Pipes

2011 ◽  
Vol 301-303 ◽  
pp. 870-875
Author(s):  
Ye An Yin ◽  
Kirill Horoshenkov ◽  
Gui Bing Ou
Keyword(s):  
Inverse Problem ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Optimization Method ◽  
Full Information ◽  
Element Modeling ◽  
Eigen Value ◽  
Eigen Values ◽  
Discrete Domain

This paper presents an approach to determination of acoustic admittances by solving inverse problem which is obtained from finite element modeling. The authors detail the inverse problem and its general eigen-function and introduce an optimization method to obtain boundary conditions by known geometries in a discrete domain and the lowest propagating frequencies and their corresponding attenuations. This method is practical because it only needs few eigen value information rather than full information of the eigen values. Comparison of acoustic experimental results and calculated results, which match well, is given to validate the method.

scholarly journals Determination of kinetic parameters for pressed tetranitropentaerytrite according to results of ODTX experiments

2019 ◽  
pp. 57-64
Author(s):  
Y. S. Zuev ◽  
N. I. Karmanov
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Kinetic Parameters ◽  
Satisfactory Agreement ◽  
Software Package ◽  
Analytical Dependence ◽  
Analysis Software ◽  
Element Analysis

The paper introduces a method for determining kinetic parameters for the pressed explosive tetranitropentaerytrite. This method includes analytical dependence for the period of induction, which is used to process the experimental data, and the ANSYS CFD finite element analysis software package. The found values of the kinetic parameters made it possible to obtain a satisfactory agreement between the calculated and experimental ignition distances for pressed tetranitropentaerytrite

Contributions to Soil Resistance Mapping for Increasing Parts Durability for Agricultural Machinery

2014 ◽  
Vol 657 ◽  
pp. 534-538
Author(s):  
Sergiu Lungu ◽  
Dragoş Paraschiv ◽  
Ion Antonescu ◽  
Eugen Enculescu ◽  
Doru Bardac
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Penetration Resistance ◽  
Solid Model ◽  
Soil Resistance ◽  
Agricultural Machinery ◽  
3D Finite Element

The Paper Presents a Study Conducted by the Authors for Mapping of Soil Resistance According to Depth and Space. the Determination of Penetration Resistance Pressure of the Soil was Done in Field, with a Penetrograph, and the Experimental Data were Statistically Analyzed, in Order to Assess the Loading Regimes Faced by the Active Organs of Agricultural Machinery while Working for Soil Processing, for Estimating the Influences on their Durability. A Durability Case Study on a Real Reversible Chisel Type Cultivator Blade was also Conducted, Using a 3D Finite Element Solid Model and Two Classical 2D Models in Order to Determine its Fatigue Response, Using as Loads the Determined Soil Resistance Pressure.

scholarly journals The Use of Imposed Displacements to Determine Impact Forces in a Multiple Blade Shed Incident

1993 ◽  
Author(s):  
T. B. Dewhurst ◽  
P. Tang
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Accurate Determination ◽  
Physical Reality ◽  
Dynamic Finite Element ◽  
Impact Forces ◽  
Finite Element Procedure ◽  
Accurate Numerical Solution ◽  
Selection Of

Experimental data from a multiple blade shed incident is used to determine the forces exerted by the blades on a containment ring. A transient, dynamic, finite element procedure is used to model the ring during the blade shed. This work focuses on the selection of the proper numerical parameters that lead to a stable and accurate numerical solution while maintaining physical reality. Examination of the degree of implicitness and various measures of damping, as well as incorporation of large displacement algorithms, has lead to a simulation that successfully determines the forces on the ring. Accurate determination of these forces is necessary for optimal design of containment systems.

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