scholarly journals Numerical modeling of three-dimensional open elastic waveguides combining semi-analytical finite element and perfectly matched layer methods

2015 ◽  
Vol 344 ◽  
pp. 158-178 ◽  
Author(s):  
K.L. Nguyen ◽  
F. Treyssède ◽  
C. Hazard
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Three Dimensional ◽  
Perfectly Matched Layer ◽  
Elastic Waveguides

Spreadsheet Tool for Quick-Turn 3D Numerical Modeling of Package Thermal Performance With Non-Uniform Die Heating

2001 ◽  
Author(s):  
Abhay A. Watwe ◽  
Ravi S. Prasher
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Finite Volume ◽  
Thermal Performance ◽  
Three Dimensional ◽  
3D Numerical Modeling ◽  
Conventional Analysis ◽  
Time Required ◽  
The Impact ◽  
Fourier Equation

Abstract Traditional methods of estimating package thermal performance employ numerical modeling using commercially available finite-volume or finite-element tools. Use of these tools requires training and experience in thermal modeling. This methodology restricts the ability of die designers to quickly evaluate the thermal impact of their die architecture due to the added throughput time required to enlist the services of a thermal analyst. This paper describes the development of an easy to use spreadsheet tool, which performs quick-turn numerical evaluations of the impact of non-uniform die heating. The tool employs well-established finite-volume numerical techniques to solve the steady-state, three-dimensional Fourier equation of conduction in the package geometry. Minimal input data is required and the inputs are customized using visual basic pull-down menus to assist die designers who may not be thermal experts. Data showing comparison of the estimates from the spreadsheet tool with that obtained from a conventional analysis using the commercially available finite element code ANSYS™ is also presented.

A Study on PHC Pipe Pile Spur Dikes Three-Dimensional Finite Element Numerical Modeling in the Lower of Yellow River

2011 ◽  
Vol 243-249 ◽  
pp. 4670-4674
Author(s):  
Zhong Fu Wang ◽  
Min Zhou ◽  
Bao Shen Zhang
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Yellow River ◽  
Three Dimensional ◽  
Structure Design ◽  
Spur Dike ◽  
Pipe Pile ◽  
Dimensional Finite Element ◽  
Spur Dikes ◽  
Three Dimensional Finite Element

Based on the analyses of the traditional rockfill groins of spur dikes，the PHC pipe pile groin is presented.The functions of the riverwall protection function, anti-erosion performance, and structure design of the groin were analyzed. By the three-dimensional finite element numerical modeling, when the scour depth of spur dike is 20m, the safty coefficient of spur dike is 1.21 and the maximum deformation is 1.3 centimeter. The studies are shown that the PHC pipe pile have high strength, stability and anti-erosion performance; The deign of double-row pile is applied to the head of spur dike where the displacement is maximum and improves stress boundary condition of the spur dike and improves the whole stability effectively.

Finite Element Simulation of Ultrasound Propagation in Trabecular Bone

2013 ◽  
Author(s):  
Behzad Vafaeian ◽  
Yuchin Wu ◽  
Michael R. Doschak ◽  
Marwan El-Rich ◽  
Tarek El-Bialy ◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Wave Propagation ◽  
Trabecular Bone ◽  
Quantitative Ultrasound ◽  
Three Dimensional ◽  
Osteoporotic Bone ◽  
Ultrasound Propagation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Quantitative ultrasound is used to identify healthy versus osteoporotic bone. However the physics of ultrasound propagation in trabecular media is still not sufficiently understood. This lack of understanding is reported to be an obstacle in further development of this bone assessment technique. Numerical models of wave propagation stand as a potentially successful tool to explain the various experimental observations. The main issue in the numerical modeling of wave propagation in trabecular bone is the complex geometry of the trabecular structures surrounded by a fluid (bone marrow). So far, the complex geometrical domain of trabecular structures has been approximated by finite difference grids for wave propagation analyses. In this work, numerical simulation of ultrasound propagation into trabecular bone sample is performed using the finite element method (FEM). A new procedure for numerical modeling of trabecular bone tailored for the FEM is introduced. The entire complex trabecular geometries of two cubic bone samples are reconstructed using computed microtomography data. For the first time a three dimensional finite element mesh using tetrahedral elements is generated for the two-phase medium of a trabecular bone. Separate meshes for the bony part and the filling marrow (considered as non-viscous water) are generated and acoustic-structure interaction condition is imposed on their interface. It is shown that the three-dimensional simulation using the FEM can predict ultrasound propagation phenomena observed in experiments: linear dependency of attenuation on frequency, the effect of bone volume on the attenuation and speed of sound, and the propagation of fast and slow waves. Moreover, the broadband ultrasound attenuation (BUA) for two ultrasonic signals propagating into a healthy and an osteoporotic sample are compared. A distinguishable difference in BUA between the two samples is observed expressing lower BUA for osteoporotic bone. Our developed model is the first three-dimensional finite element analysis model to compare the ultrasound propagation in healthy versus osteoporotic bone. The developed model can be further utilized as a tool to explain various experimental observations of quantitative ultrasound of bone.

scholarly journals Bone Stress-Strain State Evaluation Using CT Based FEM

2021 ◽  
Vol 7 ◽  
Author(s):  
Oleg V. Gerasimov ◽  
Nikita V. Kharin ◽  
Artur O. Fedyanin ◽  
Pavel V. Bolshakov ◽  
Maxim E. Baltin ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
Numerical Modeling ◽  
Three Dimensional ◽  
Physical Experiment ◽  
Qualitative Assessment ◽  
Element Analysis ◽  
Crack Location ◽  
External Forces ◽  
Tomography Data

Nowadays, the use of a digital prototype in numerical modeling is one of the main approaches to calculating the elements of an inhomogeneous structure under the influence of external forces. The article considers a finite element analysis method based on computed tomography data. The calculations used a three-dimensional isoparametric finite element of a continuous medium developed by the authors with a linear approximation, based on weighted integration of the local stiffness matrix. The purpose of this study is to describe a general algorithm for constructing a numerical model that allows static calculation of objects with a porous structure according to its computed tomography data. Numerical modeling was carried out using kinematic boundary conditions. To evaluate the results obtained, computational and postprocessor grids were introduced. The qualitative assessment of the modeling data was based on the normalized error. Three-point bending of bone specimens of the pig forelimbs was considered as a model problem. The numerical simulation results were compared with the data obtained from a physical experiment. The relative error ranged from 3 to 15%, and the crack location, determined by the physical experiment, corresponded to the area where the ultimate strength values were exceeded, determined by numerical modeling. The results obtained reflect not only the effectiveness of the proposed approach, but also the agreement with experimental data. This method turned out to be relatively non-resource-intensive and time-efficient.

scholarly journals Finite Element Analysis in Combination with Perfectly Matched Layer to the Numerical Modeling of Acoustic Devices in Piezoelectric Materials

2013 ◽  
Vol 04 (05) ◽  
pp. 64-71 ◽  
Author(s):  
Dbich Karim ◽  
Sylvain Ballandras ◽  
Thierry Laroche ◽  
Karl Wagner ◽  
Jean-Michel Brice ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Modeling ◽  
Piezoelectric Materials ◽  
Perfectly Matched Layer ◽  
Element Analysis

scholarly journals Numerical modeling of the contact between three-dimensional regions with the use of FEM

2018 ◽  
Vol 157 ◽  
pp. 08009
Author(s):  
Tomasz Skrzypczak ◽  
Ewa Węgrzyn-Skrzypczak ◽  
Leszek Sowa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Finite Elements ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Mechanical Interaction ◽  
The Finite Element Method ◽  
Three Dimensional Objects ◽  
Original Program

The numerical approach based on the finite element method (FEM) for modeling of mechanical interaction between three-dimensional objects is presented in the paper. The model of contact is based on the assumption that the nodes of the region which is the source of contact cannot overlap with the nodes of the region being the target. The procedure of the detection of collision between surfaces of the source and the target is discussed in details. The behaviour of surfaces being in contact depends on their rigidity and is numerically modeled in the case of perfectly rigid source and deformable target. Each modeled object has an independent mesh of finite elements. These meshes can be freely moved relative to each other. Example of calculation using original program written in C++ is presented and discussed.

Experimental determination and numerical modeling of the stiffness of a fastener

2020 ◽  
Vol 62 (12) ◽  
pp. 1215-1220
Author(s):  
Ahmet Atak
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
Finite Element Model ◽  
Computational Cost ◽  
Three Dimensional ◽  
Sandwich Panels ◽  
High Strength ◽  
Element Model ◽  
Secondary Structures ◽  
Element Analysis

Abstract To reduce the fuel consumption and enhance the flight performance of satellites, it is desirable to employ structural components of low weight, high strength, and high stiffness. Therefore, most primary and secondary structures of satellites are built using sandwich panels. Fasteners, which constitute secondary structures, are normally used as joining parts in different types of inserts such as partially potted, fully potted, and through-thickness inserts. Finite element analysis (FEA) is valuable for predicting the behavior of such primary and secondary structures. However, to obtain more realistic results from such analysis, it is necessary to define suitable fastener stiffness values. To this end, in this study, a method for calculating the fastener stiffness of a fully potted insert for sandwich panels using a finite element model is exemplarily developed and experimentally validated. In addition, a shell modeling is established for various connection types to further save time and reduce the computational cost of the finite element model. Finally, the effects of the fastener stiffness on the numerical analysis results for satellite structural system are evaluated. The two-dimensional (2D) structure modeling method used in this study was found to be as fully sufficient as three-dimensional modeling. In addition to saving time and cost, 2D FEA numerical modeling and prediction could reduce elaborate test costs.

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