Forced Response of Disks due to Distributed Pressure Fields

2001 ◽  
Author(s):  
A. H. Mohamad ◽  
J. Ravoux ◽  
G. Jacquet-Richardet
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Analytical Model ◽  
Forced Response ◽  
Major Influence ◽  
Finite Element Models ◽  
Circular Plates ◽  
Element Modeling ◽  
Pressure Fields ◽  
Distributed Pressure

Abstract The shape and the frequency of excitation, induced by distributed pressure fields, have both a major influence on the associated response of bladed disks. The way those pressure fields are considered by finite element models have then to be as accurate as possible. In this paper, an analytical model, adapted to the prediction of the forced response of clamped-free circular plates, due to distributed pressure fields, is first derived. This model is considered as a reference in order to assess the effectiveness of different finite element modeling.

EVALUATION OF ANALYTICAL AND FINITE ELEMENT MODELING ON PIEZOELECTRIC CANTILEVER BIMORPH ENERGY HARVESTER

2013 ◽  
Vol 37 (3) ◽  
pp. 621-629 ◽  
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zhengchao Xie
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Analytical Model ◽  
Energy Harvester ◽  
Electrical Energy ◽  
Working Environment ◽  
Dynamic Responses ◽  
Power Sources ◽  
Element Modeling ◽  
Piezoelectric Cantilever

Harvesting the electrical energy from their working environment has become a feasible choice of realizing self-powered systems or providing supplementary power sources to the battery. In this paper, a pre-loaded piezoelectric cantilever bimorph (PCB) energy harvester is adopted as the research object, for which a single degree-of-freedom analytical model and finite element modeling have been carried out to study its dynamic responses. The laboratory experiments have also been performed to validate the analytical and the finite element modeling. It shows that finite element modeling has a better agreement with the experimental results than the analytical model, while the latter has a rough accuracy and can be used to obtain quick estimations of the dynamic response of the PCB energy harvester in certain cases.

Finite Element Modeling for Optimizing Hermetic Package Reliability

1989 ◽  
Vol 111 (4) ◽  
pp. 255-260 ◽  
Author(s):  
J. H. Lau ◽  
L. B. Lian-Mueller
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimal Design ◽  
Thermal Behavior ◽  
Finite Element Modeling ◽  
Thermal Stresses ◽  
Finite Element Models ◽  
The Finite Element Method ◽  
Element Modeling ◽  
Package Reliability

The thermal stresses in microwave packages are studied by the finite element method. Emphasis is placed on the effects of material construction and design on the reliability of very small hermetic packages. Three different microwave packages have been designed and six finite element models (two for each design) have been analyzed. To verify the validity of the finite element results, some leak tests have been performed and the results agree with the analytical conclusions. The results presented herein should provide a better understanding of the thermal behavior of hermetic packages and should be useful for their optimal design.

Automated Finite Element Modeling of Tube Frame Structure Parametric Design

2002 ◽  
Author(s):  
Robert R. Mayer ◽  
Ashok Vaishnav
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Model Building ◽  
Parametric Design ◽  
Finite Element Mesh ◽  
Frame Structure ◽  
Finite Element Models ◽  
Element Mesh ◽  
Element Modeling ◽  
Finite Element Meshes

This research was intended to address the last step in the development of a tube-frame (termed B2B) parametric crashworthiness model - automated finite element modeling of the parametric design. We have added the generation of finite element models to the previously built Unigraphics Version 16 (UG V16) parametric model, so that finite element models could be quickly built. UG/WAVE was used to design the vehicle parametrically and UG/SCENARIO, a pre- and post-processor integrated in UG, was used to automatically construct the finite element mesh. We established the quality of the finite element meshes, generated for two new designs, which were created by changing overall dimensions of the vehicle. This was done using objective criteria for the finite element mesh. The component data was added to the automatically generated mesh, and the results from the crashworthiness analysis of this model compared favorably with the ‘hand-built’ model using traditional model building techniques. The results from this work will be useful in the development of the parametric design process. The use of automatically generated finite element meshes will also be useful for the automated evaluation of these parametric designs.

scholarly journals Study of the Hershel-Quinke Resonator

2020 ◽  
Vol 320 ◽  
pp. 00025
Author(s):  
Veronika Nikolaeva ◽  
Alexandr Komkin
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Analytical Model ◽  
Transmission Loss ◽  
Geometric Parameters ◽  
Numerical Calculations ◽  
Element Modeling

In this paper, the transmission loss of a Herschel-Quincke resonator is investigated. An analytical model of such a resonator is considered. The finite element modeling of the resonator has also been carried out. It is shown that the resonance peaks of the transmission loss spectrum in the analytical model are shifted relative to the results of numerical calculations, as a result of which it is necessary to introduce corrections for the length of the resonator tubes into the analytical model. The amendments made it possible to correct the results of analytical calculations, ensuring their reliability. The dependence of the resonator bandwidth as a function of its geometric parameters is investigated.

Finite Element Modeling of Rollover Crash Tests With Hybrid III Dummies

2007 ◽  
Author(s):  
Keith Friedman ◽  
John Hutchinson ◽  
Dennis Mihora
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
The United States ◽  
Finite Element Models ◽  
Element Modeling ◽  
Roof Structure ◽  
Hybrid Iii ◽  
The Impact ◽  
Rollover Crash ◽  
Crash Tests

This paper reports on the finite element modeling of rollover crash tests with Hybrid III dummies. Finite element models of a vehicle design and the Hybrid III dummy were used to evaluate the subsystem under manufacturer created rollover conditions for a production and roll caged roof structure. The objective of this study was to demonstrate the ability to reproduce the impact environment occurring in rollover crash tests. There are over 26,000 fatalities and serious injuries annually occurring in rollover accidents in the United States. Many of these are to restrained occupants and their head and spinal injuries have been associated with contact with the roof structure. To analyze the crash tests the effects of the system, finite element models were made of rollover crash tests that had been conducted using baseline and modified passenger vehicles and Hybrid III dummies using the defined impact conditions. Neck loads were utilized to validate the model against the test results. The results show that finite element modeling can reproduce the results from rollover crash tests.

Finite Element Modeling and Modal Analysis of Coilable Mast

2012 ◽  
Vol 226-228 ◽  
pp. 299-302
Author(s):  
Jie Wang ◽  
Dong Xu Li ◽  
Jian Ping Jiang
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Space Mission ◽  
Joint Model ◽  
Finite Element Models ◽  
Attached Mass ◽  
Element Modeling ◽  
Tension Level

This paper investigates the modal characteristics of a coilable mast for space mission applications. Finite element models are established for characterizing the coilable mast. The simplification of joints between longerons and batten frames and the pre-tension in cables are carefully considered. A parametric modal analysis is performed with considering the following factors, the joint model in the truss, the pre-tension in cables, elements selected for longerons and battens, the mass attached to the top of the mast. Research results show that the natural frequencies of the coilable mast are sensitive to the selected elements and the attached mass. The pre-tension level in cables and the precision degree of the joint model have little effect on natural frequencies. The regularity expressed in the parametric modal analysis is useful for designers and engineers.

scholarly journals The problem of mathematical finite element modeling of inhomogeneous deformable solids using scanning

2019 ◽  
Vol 19 (3) ◽  
pp. 281-289
Author(s):  
V. L. Duong
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Strain State ◽  
Mechanical Characteristics ◽  
Finite Element Models ◽  
Mathematical Methods ◽  
Stress Strain ◽  
Computer Tomograph ◽  
Element Modeling ◽  
Deformable Solids

Introduction. In the mathematical finite element modeling, an average value of the mechanical characteristics of the deformable solid material is used. In aircraft, machine building, construction engineering, medicine and other fields, polymer composite materials and materials of natural origin are increasingly used. In the latter case, the actual change in the mechanical characteristics differs significantly from the averaged change; therefore, when using the averaged parameters to build and analyze finite element models, the results can be significantly distorted. This paper describes the creation of mathematical methods for studying changes in the mechanical characteristics of a material of inhomogeneous deformable solids. The results obtained in this way are used to construct finite element models and analyze their stress-strain state.Materials and Methods. Naturally occurring materials and composites are considered as inhomogeneous deformable solids. To study the changes in the mechanical characteristics of the material, a method was developed based on the use of two components: the pixel characteristics of raster images scanned by a computer tomograph and the experimental data of field tests of standard samples.Research Results. A complex of mathematical methods has been developed for modeling the interpretation of scanning raster images by a computer tomograph, which allows for the study of any complicated structures of real deformable solids. The results are used in the construction of finite element models of such bodies considering the heterogeneity of the mechanical characteristics of the material. The analysis of the stress-strain state of finite element models of test samples has proved the accuracy and convergence of the numerical solution of the finite element method in modeling the property of heterogeneity of the mechanical characteristics of the material.Discussion and Conclusions. The developed approach can be applied to any physical principles of scanning (X-ray, ultrasound, laser, etc.) and for any types of materials if the data obtained as a result of scanning is developed in the form of a digital (raster) image.

Influence of Finite Element Modeling Choices in the Assessment of Stress Concentrations at Fatigue Prone Locations in Orthotropic Bridge Decks

2012 ◽  
Vol 525-526 ◽  
pp. 37-40 ◽  
Author(s):  
Wouter de Corte ◽  
Arne Jansseune
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Bridge Decks ◽  
Full Scale ◽  
Major Influence ◽  
Stress Concentrations ◽  
Numerical Work ◽  
Element Modeling ◽  
Mesh Density ◽  
Full Scale Tests

In orthotropic bridge decks, the rib to floorbeam connection is a major source of fatigue problems. Commonly, the trapezoidal ribs cross the floorbeam continuously necessitating clearance holes in its web, and frequently additional web cutouts are foreseen to relieve the ribs lower edges. This solution is favorable for rib cracking but will generate stress concentrations in the web itself. The shape of the additional cutout has a major influence on the sizes of the concentrations rendering differences of a factor 2 or 3 for corresponding overall geometries and loading schemes. Various authors have studied cutout shapes through full scale testing or by computation by finite element modeling. This paper presents such a study, but focuses on the influence of the finite element modeling itself. It is shown that the mesh density, the element type, the choice between shell and volume elements. This is an important finding and should not be overlooked when comparing finite element based results to coded values or measured results. In order to do so, the results of the numerical work are compared to strain results from full scale tests.

Constrained Damping Layer Treatments: Finite Element Modeling

2004 ◽  
Vol 10 (4) ◽  
pp. 575-595 ◽  
Author(s):  
R. Moreira ◽  
J. D. Rodrigues
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Viscoelastic Material ◽  
Spatial Modeling ◽  
Complex Modulus ◽  
Dynamic Properties ◽  
Finite Element Models ◽  
Constrained Layer Damping ◽  
Element Modeling ◽  
Constrained Damping

In this paper we assess the performance of finite element models in modeling structures with sheer damping treatments. We analyze the finite element modeling of constrained layer damping (CLD) and integrated layer damping (ILD) treatments using viscoelastic materials, devoting special attention to the spatial modeling of the treatment and to the characterization of the viscoelastic material properties. In this work, we used a finite element commercial software (MSC.Nastran) to simulate the dynamic response of aluminum plates with both treatment configurations (CLD and ILD). The spatial modeling of the treatment was devel-oped using three different models, all based on a layered assembly of plate/brick conventional finite elements. The dynamic properties of the viscoelastic material were taken into account in the numerical simulation using the complex modulus approach. The numerical results are correlated with experimental data obtained for four treated specimens by direct comparison of the frequency response functions (FRFs) and by using FRF-based correlation indicators. The analyzed finite element models are found to provide very reliable results when compared with experimental acquired data.

3D Finite Element Modeling of Buried Pipelines: On the Interaction of Beam Action of Pipelines and Cross Sectional Behavior

2004 ◽  
Author(s):  
Max A. N. Hendriks ◽  
C. Marcel P. ’t Hart ◽  
Chantal M. Frissen
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Simple Problem ◽  
Finite Element Models ◽  
Buried Pipelines ◽  
Cross Sectional ◽  
Sand Waves ◽  
Element Modeling ◽  
Beam Elements ◽  
3D Effects

A common finite element modeling approach for buried pipelines is the combined use of beam and spring elements. Typical loads are soil settlements, temperature variations, internal pressures, neutral topsoil weight load and traffic loads. The beam elements represent the pipeline; assemblies of spring elements represent the surrounding soil comprising an elastoplastic bedding with friction. The choice for such finite element models is a pragmatic one. The models are relatively easy to construct and the analyses can be performed within reasonable calculation time on an average PC. From a mechanical point of view the problem of a buried pipeline subjected to subsidence, or an offshore pipeline subjected to sand waves, is of a full 3D nature. Beam elements and spring elements only partly incorporate full 3D effects. In practice the common finite element models are therefore enhanced to take into account 3D effects that would be otherwise omitted. A major point is the distinction between beam action and cross sectional behavior of pipes in straight and curved sections and their mutual interaction. This paper discusses the pros and cons of two possible finite element approaches which deal with this full 3D problem. In the final example it is illustrated that the two approaches gives similar results for the relatively simple problem of a buried bended pipe subjected to a temperature load and internal pressure.

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