ADINA Publications

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The Theory used in ADINA is richly documented in the following books by K.J. Bathe and co-authors


Finite Element Procedures
 

Finite Element Procedures in Engineering Analysis

Numerical Methods in Finite Element Analysis
 


The Mechanics of Solids and Structures — Hierarchical ...


The Finite Element Analysis of Shells — Fundamentals


Inelastic Analysis of Solids and Structures

 
 
To Enrich Life
(Sample pages here)
 

 

Following are more than 700 publications — that we know of — with reference to the use of ADINA. The pages give the Abstracts of some papers published since 1986 referring to ADINA. The most recent papers are listed first. All these papers may be searched using the box:

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Effects of One-Way and Two-Way Directional Heavy Vehicle Simulator Loading on Rutting in Hot Mix Asphalt Pavements

M. Novak1, B. Birgisson1, R. Roque1, B. Choubane2

1University of Florida, Department of Civil and Coastal Engineering, P.O. Box 116580, Gainesville, FL 32611-6580
2Florida Dept. of Transportation, Materials Research Park, 5007 N.E. 39th Avenue, Gainesville, FL 32609

Proc. TRB 2004 Annual Meeting, 2004

Abstract: Instability rutting generally occurs within the top five centimeters (two inches) of the asphalt layer when the structural properties of the asphalt concrete are inadequate to resist the stresses imposed upon it. It is generally believed that near-surface transverse shear stresses perpetuate instability rutting. Field observations of Heavy Vehicle Simulator (HVS) testing noted greater rutting in one-way directional loading compared to two-way directional loading, even at lower temperatures and with longer rest periods between load applications. An analysis of stress states in the asphalt pavement layer using the three-dimensional finite element commercial code ADINA showed that longitudinal stress path patterns varied between the different directional loadings. A hypothesis was developed that the differences in longitudinal plane stress path patterns between one-way and two-way directional loading attributed to the different levels of rutting. A visco-elastic model with load applications simulating the different directional loadings was constructed and used to test this hypothesis. The visco-elastic model results indicated qualitatively that even with greater relaxation times, one-way directional loading produces greater strains.

Keywords: Instability Rutting - Heavy Vehicle Simulator - Finite Element Analysis - Stress Path Patterns

Finite Element Analysis of Active Eustachian Tube Function

Samir N. Ghadiali1,2,3, Julie Banks3, J. Douglas Swarts2,3

1Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015
2Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
3Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania 15213

J Appl Physiol, March 26, 2004

Abstract:
The inability to open the collapsible Eustachian tube (ET) has been related to the development of chronic Otitis Media. Although ET dysfunction may be due to anatomical and/or mechanical abnormalities, the precise mechanisms by which these structural properties alter ET opening phenomena have not been investigated. Previous investigations could only speculate on how these structural properties influence the tissue deformation processes responsible for ET opening. We have therefore developed a computational technique that can quantify these structure-function relationships. Cross-sectional histological images were obtained from 8 normal adult human subjects with no history of middle ear disease. A midcartilaginous image from each subject was used to create two-dimensional finite element models of the ET’s soft tissue structures. ET opening phenomena were simulated by applying muscle forces on soft tissue surfaces in the appropriate direction and were quantified by calculating the resistance to flow in the opened lumen (Rv). A sensitivity analysis was conducted to determine the relative importance of muscle forces and soft tissue elastic properties. Muscle contraction resulted in a medial-superior rotation of the medial lamina, stretching deformation in the Ostmann’s fatty tissue and lumen dilation. Variability in baseline Rv values correlated with tissue size while the functional relationship between Rv and a given mechanical parameter was consistent in all subjects. ET opening was found to be highly sensitive to the applied muscle forces and relatively insensitive to cartilage elastic properties. These computational models have therefore identified how different tissue elements alter ET opening phenomena, which elements should be targeted for treatment and the optimal mechanical properties of these tissue constructs.

Keywords: Young’s modulus - biomechanics - elasticity - respiratory airway - compliance - fluid-structure interactions - mathematical modeling

 

Characterization of the Atherosclerotic Carotid Bifurcation Using MRI, Finite Element Modeling, and Histology

M. R. Kaazempur-Mofrad,1,5 A.G. Isasi,1 H.F. Younis,1 R.C. Chan,2 D.P. Hinton,2 G. Sukhova,3 G.M. Lamuraglia,4 R. T. Lee,3 and R.D. Kamm1

1 Department of Mechanical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA;
2 Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA;
3 Department of Cardiovascular Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA;
4 Department of Vascular Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA; and
5 Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA

Annals of Biomedical Engineering, 32(7): 932–946, 2004

Abstract: Atherogenesis is known to be associated with the stresses that act on or within the arterial wall. Still, the uneven distribution of atherosclerotic lesions and the impact of vessel remodeling on disease progression are poorly understood. A methodology is proposed to study the correlations between fluid dynamic parameters and histological markers of atherosclerosis. Trends suggested by preliminary data from four patients with advanced carotid bifurcation arterial disease are examined and compared to hypotheses in the literature. Four patients were scanned using MRI and ultrasound, and subsequently underwent carotid endarterectomy. For each patient, a geometric model and a numerical mesh were constructed fromMRdata, and velocity boundary conditions established. Computations yield values for average wall shear stress (WSS), maximum wall shear stress temporal gradient (WSSTG), and Oscillatory Shear Index (OSI). Following surgery, the excised plaques were sectioned, stained for smooth muscle cells (SMC), macrophages (Mf), lipid (LIP), and collagen (COL), and analyzed quantitatively. Correlations attempted between the various fluid dynamic variables and the biological markers were interesting but inconclusive. Tendencies of WSSTG and WSS to correlate negatively with Mf and LIP, and positively with COL and SMC, as well as tendencies of OSI to correlate positively with Mf and LIP and negatively with COL and SMC, were observed. These trends agree with hypotheses in the literature, which are based on ex vivo and in vitro experimental studies.

Keywords: Atherosclerosis — MRI — FEM — Carotid 3D geometry — Low/oscillatory shear stress — Excised plaque composition

 

Seismic Upgrade Of Oak Street Bridge With Gfrp

Y.Ding, B. Hamersley

Klohn Crippen Consultants, Vancouver, BC, Canada

Proc. 13th World Conference on Earthquake Engineering, 2004

Abstract: Vancouver’s 2 km long Oak Street Bridge was constructed in the 1950’s across the North Arm of the Fraser River. The south approach consists of continuous cast-in-place concrete girders founded in liquefiable soils. The structure required protection from movements caused by soil liquefaction, as part of a comprehensive upgrade. Klohn Crippen was retained to examine structural alternatives for improving the girders’ ability to accommodate the pier movements. Detail finite element analysis indicated that should the piers settle in an earthquake the bridge’s under-reinforced girders would be expected to form single flexural cracks at the positive moment region of the girders, which would open wide enough to rupture the reinforcing. Various strengthening methods were studied including steel plates, carbon fiber reinforced polymer wraps, and glass fiber reinforced polymer wraps. Composites provided cost and aesthetic  advantages over steel plates. Glass fiber was chosen for design because it was considered the most flexible of the composites, which would accommodate the required level of settlement without brittle failure of the structure. The retrofit was completed in 2002 and resulted in cost savings in excess of $1 million over the ground improvement alternative.

 

Seismic analysis of the new Tacoma Narrows suspension bridge

M.Jones1, S. Treyger2 and P.Pence3

1 Project Manager, HNTB Corporation, Santa Ana, USA.
2 Associate Vice President, HNTB Corporation, Seattle, USA.
3 Senior Project Engineer, HNTB Corporation, Santa Ana, USA.

Proc. 13th World Conf. on Earthquake Engineering, 2004

Abstract: This paper presents the seismic analysis that was conducted for the new Tacoma Narrows Suspension Bridge, which is located in the Seattle-Tacoma area of the State of Washington. This area is in a high seismicity region, capable of producing earthquakes of Richter moment magnitude eight or larger. Project specific performance-based design criteria mandated that a non-linear time-history analysis be used to supply the bridge with prescribed levels of seismic resistance. Some of the analysis subjects discussed include damping, soil-structure interaction, caisson rocking, hydrodynamic mass, and finite element modeling of various bridge components. The paper demonstrates that analysis techniques are available to confirm that seismic goals specified by performance-based design criteria are achievable for bridges in high seismic regions.

 

Relation Between Vertical Orientation and Stability of Acetabular Component in the Dysplastic Hip Simulated by Nonlinear Three-dimensional Finite Element Method

H. Oki, M. Ando, H. Omori, Y. Okumura, K. Negoro, K. Uchida, and H. Baba

Department of Orthopaedic Surgery, Faculty of Medicine, University of Fukui, Matsuoka, Fukui, Japan

Artificial Organs, 28(11): 1050-1054, 2004

Abstract: In acetabular dysplasia, more vertical orientation of the acetabular component is often used to minimize the superolateral bone grafting. This study was designed to determine the effects of vertical orientation of the cup on the stability and polyethylene wear of the acetabular component in uncemented total hip arthroplasty (THA). Three-dimensional finite element models of the hemipelvis with dysplastic acetabulum were developed. Metal-backed hemispherical cups were placed in the true acetabulum with abduction angles of 35, 45, 55, and 65 degrees. It was found that more vertical orientation of the cup was associated with larger relative motion of the metal shell between the acetabulum and metal shell. Furthermore, tilting and torsional shear stresses in the model of the cup abduction angle of 65 degrees were found to be 1.7 times larger than that in the model with 35 degrees at the bone–metal shell interface. More vertically oriented cups caused larger contact stresses at the articulating surfaces of the polyethylene liners. The results suggest that the abduction angle of the acetabular component significantly influences cup loosening and polyethylene wear in THA.

Keywords: Cup abduction angle — Acetabular component — Relative motion — Shear stress — Contact stress

 

Computational modeling of flow over an ogee spillway

Chatila, Jean (Department of Civil Engineering, Sch. of Engineering and Architecture, Lebanese American University); Tabbara, Mazen Source: Computers and Structures, v 82, n 22, September, 2004, p 1805-1812

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Ltd

Abstract: This paper presents an investigation into the hydraulics of regular ogee-profile spillways. The free-surfaces of the fluid for several flow heads as measured in the hydraulics laboratory are used as benchmarks. The finite element computational fluid dynamics software, ADINA, was used to predict the free surface over an ogee spillway and thus model the flow field. Since the actual flow is turbulent the k-ε flow model was used. For the cases considered in this paper, ADINA predicted reasonable free surface results that are consistent with general flow characteristics over spillways. The results are also in close agreement with measured free-surface profiles over the entire length of the spillway. © 2004 Elsevier Ltd. All rights reserved. (30 refs.)

Keywords:  Spillways  -  Hydraulics  -  Surface phenomena  -  Turbulent flow  -  Benchmarking  -  Finite element method  -  Computational fluid dynamics  -  Numerical analysis  -  Mathematical models

Secondary  Keywords:  Ogee-spillway  -  Numerical  -  Experimental  -  Modeling  -  Free surface  -  Finite element

 

 

Mechanical analysis of atherosclerotic plaques based on optical coherence tomography

Alexandra H. Chau,1,2 Raymond C. Chan,2 Milen Shishkov,2 Briain Macneill,2 Nicusor Iftimia,2 Guillermo J. Tearney,2 Roger D. Kamm,1 Brett E. Bouma,2 And Mohammad R. Kaazempur-Mofrad1

1Department of Mechanical Engineering and Biological Engineering Division, Massachusetts Institute of Technology, Cambridge, MA 02139

2Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114

Annals of Biomedical Engineering, Vol. 32, No. 11, pp. 1494–1503, 2004

Abstract: Finite element analysis is a powerful tool for investigating the biomechanics of atherosclerosis and has thereby provided an improved understanding of acute myocardial infarction. Structural analysis of arterial walls is traditionally performed using geometry contours derived from histology. In this paper we demonstrate the first use of a new imaging technique, optical coherence tomography (OCT), as a basis for finite element analysis. There are two primary benefits of OCT relative to histology: 1) imaging is performed without excessive tissue handling, providing a more realistic geometry than histology and avoiding structural artifacts common to histologic processing, and 2) OCT imaging can be performed in vivo, making it possible to study disease progression and the effect of therapeutic treatments in animal models and living patients. Patterns of mechanical stress and strain distributions computed from finite element analysis based on OCT were compared with those from modeling based on “gold standard” histology. Our results indicate that vascular structure and composition determined by OCT provides an adequate basis for investigating the biomechanical factors relevant to atherosclerosis and acute myocardial infarction.

Keywords: Optical coherence tomography (OCT) - FEM - Atherosclerotic plaques

 


A coupled elastoplastic damage model for geomaterials

Salari, M.R. (Dept. of Civil Environ./Arch. Eng., Univeristy of Colorado); Saeb, S.; Willam, K.J.; Patchet, S.J.; Carrasco, R.C. Source: Computer Methods in Applied Mechanics and Engineering, v 193, n 27-29, Jul 9, 2004, p 2625-2643

ISSN: 0045-7825 CODEN: CMMECC

Publisher: Elsevier

Abstract: A triaxial constitutive model is developed for elastoplastic behavior of geomaterials, which accounts for tensile damage. The constitutive setting is formulated in the framework of continuum thermodynamics using internal variables. The interaction of elastic damage and plastic flow is examined with the help of very simple constitutive assumptions: (i) a Drucker-Prager yield function is used to define plastic loading of the material in combination with a non-associated flow rule to control inelastic dilatancy; (ii) elastic damage is assumed to be isotropic and is represented by a single scalar variable that evolves under expansive volumetric strain. Thereby, positive volumetric deformations couple the dissipation mechanisms of elastic damage and plastic flow which introduce degradation of the elastic stiffness as well as softening of the strength. The constitutive model is implemented in the finite element program ADINA to determine the response behavior of the combined damage-plasticity model under displacement and mixed control. A number of load histories are examined to illustrate the performance of the material model in axial tension, compression, shear and confined compression. Thereby incipient failure is studied at the material level in the form of non-positive properties of the tangential material tensor of elastoplastic damage and the corresponding localization tensor comparing non-associative with associative plasticity formulations. © 2004 Elsevier B.V.All rights reserved. (23 refs.)

Keywords:  Geosynthetic materials  -  Elastoplasticity  -  Thermodynamics  -  Strain  -  Stiffness  -  Tensile strength  -  Plastic flow  -  Shear deformation

Secondary  Keywords:  Elastic damage  -  Continuum thermodynamics  -  Geomaterials  -  Axial tension

 


Finite element developments for general fluid flows with structural interactions

Bathe, Klaus-Jurgen (Massachusetts Inst. of Technology); Zhang, Hou Source: International Journal for Numerical Methods in Engineering, v 60, n 1, May 7, 2004, p 213-232

ISSN: 0029-5981 CODEN: IJNMBH

Publisher: John Wiley and Sons Ltd

Abstract: The objective in this paper is to present some developments for the analysis of Navier-Stokes incompressible and compressible fluid flows with structural interactions. The incompressible fluid is discretized with a new solution approach, a flow-condition-based interpolation finite element scheme. The high-speed compressible fluids are solved using standard finite volume methods. The fluids are fully coupled to general structures that can undergo highly non-linear response due to large deformations, inelasticity, contact and temperature. Particular focus is given on the scheme used to couple the fluid media with the structures. The fluids can also be modelled as low-speed compressible or slightly compressible media, which are important models in engineering practice. Some solutions obtained using ADINA are presented to indicate the analyses that can be performed. © 2004 John Wiley and Sons, Ltd. (35 refs.)

Keywords:  Flow of fluids  -  Deformation  -  Compressible flow  -  Interpolation  -  Finite element method  -  Navier Stokes equations  -  Numerical methods

Secondary  Keywords:  Discretized  -  Compressible fluids  -  Fluid media  -  Structural interactions

 

A Three-Dimensional Viscoelastic Model for Cell Deformation with Experimental Verification

Helene Karcher,* Jan Lammerding,a Hayden Huang,a Richard T. Lee,a Roger D. Kamm,* and Mohammad R. Kaazempur-Mofrad*

*Department of Mechanical Engineering and Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
aCardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts

Biophysical Journal, Volume 85, November 2003, 3336–3349

Abstract: A three-dimensional viscoelastic finite element model is developed for cell micromanipulation by magnetocytometry.  The model provides a robust tool for analysis of detailed strain/stress fields induced in the cell monolayer produced by forcing one microbead attached atop a single cell or cell monolayer on a basal substrate. Both the membrane/cortex and the cytoskeleton are modeled as Maxwell viscoelastic materials, but the structural effect of the membrane/cortex was found to be negligible on the timescales corresponding to magnetocytometry. Numerical predictions are validated against experiments performed on NIH 3T3 fibroblasts and previous experimental work. The system proved to be linear with respect to cytoskeleton mechanical properties and bead forcing. Stress and strain patterns were highly localized, suggesting that the effects of magnetocytometry are confi ned to a region extending <10 µm from the bead. Modulation of cell height has little effect on the results, provided the monolayer is >5 µm thick. NIH 3T3 fibroblasts exhibited a viscoelastic timescale of ~1 s and a shear modulus of ~1000 Pa.

 

The numerical design of a parallel plate flow chamber for investigation of endothelial cell response to shear stress

B.J. Chunga, A.M. Robertsona, D.G. Petersb

aDepartment of Mechanical Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
bDepartment of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA

Computers and Structures 81 (2003) 535–546

Abstract: Parallel plate chambers are frequently used to examine the response of biological cells to a constant wall shear stress. However, the stress can vary more than 80% across the chamber due to end effects. Earlier estimates of the magnitude of this inhomogeneity used boundary layer theory and experiments. Here, the full equations for steady, three-dimensional flow in a novel parallel plate device were solved numerically and used to identify an active test region where the shear stress is within 5% of a constant value. Endothelial cells can be con.ned to this region to assure a nearly uniform shear stress exposure.

Keywords: Parallel plate device - Shear stress - Endothelial cells - Active test region - Mechanotransduction

 

Computation of blood flow in a diaphragm-type ventricular assist device

Doyle, M. (Department of Mechanical Engineering, University of Ottawa); Tavoularis, S.; Bourgault, Y. Source: Proceedings of the IASTED International Conference on Biomechanics, Proceedings of the IASTED International Conference on Biomechanics, 2003, p 92-96

ISBN-10: 0889863598

Conference: Proceedings of the IASTED International Conference on Biomechanics, Jun 30-Jul 2 2003, Rhodes, Greece Sponsor: IASTED

Publisher: Int. Assoc. of Science and Technology for Development

Abstract: The goal of this research is to advance the use of Computational Fluid Dynamics (CFD) in modelling the operation of ventricular assist devices (VADs) connected to the circulatory system, as a cost-effective alternative to experimentation. An idealized VAD, based on a design developed by a group at Brunel University, has been chosen for this research because of the availability of experimental and computational results. The simulations are made with the use of the commercial finite element software package ADINA, which is among the few available codes with fluid-structure interaction (FSI) capabilities, as required for the modelling of fluid flows coupled with the deformation of solid components. The present VAD model consists of two rigid hemispherical chambers separated by a flexible circular diaphragm. This device is attached to compliant and resistive elements used to represent the components of the circulatory system and is run on a closed loop. Preliminary results show the feasibility of this approach and are, in order-of-magnitude, in agreement with the Brunel University results. (6 refs.)

Keywords:  Hemodynamics  -  Blood  -  Computational fluid dynamics  -  Cardiovascular surgery  -  Implants (surgical)  -  Biological membranes  -  Computational geometry  -  Mathematical models  -  Computer simulation

Secondary Keywords:  Cardiovascular implants and devices  -  FEM modeling  -  Computational blood flow  -  Fluid-structure interaction

 


Quantifying effects of controlling factors on flow and stress distribution in stenotic arteries with lipid cores

Tang, Dalin (Mathematical Sciences Dept., Worcester Polytechnic Institute); Yang, Chun; Kobayashi, Shunichi; Ku, David N. Source: American Society of Mechanical Engineers, Bioengineering Division (Publication) BED, v 55, 2003 Advances in Bioengineering, 2003, p 53-54

ISSN: 1071-6947 CODEN: ASMBEP

Conference: 2003 ASME International Mechanical Engineering Congress, Nov 15-21 2003, Washington, DC., United States Sponsor: The Bioengineering Division, ASME

Publisher: American Society of Mechanical Engineers

Abstract: 2D and 3D multi-physics experiment-based nonlinear models with fluid-structure interactions (FSI) and structure-structure interactions (SSI) are introduced to model blood flow and stress/strain distributions in stenotic arteries with lipid pools. Material properties for the vessel and plaque are based on experimental measurements and information available in the literature (Huang et. al., 2001; Tang et. al., 2001). The Navier-Stokes equations are used as the governing equations for the fluid. Mooney-Rivlin models are used for both arteries and lipid cores. A well-tested finite element package ADINA is used to solve the models to perform flow and stress/strain analysis. Our results indicate that artery plaque stress/strain distributions are affected considerably (50%-400% or even more) by vessel material properties, stenosis severity and eccentricity, tube axial pre-stretch, pressure conditions, lipid core material property, size, position and geometry, and fluid-structure and structure-structure (vessel wall and lipid core) interactions. Differences in model assumptions and controlling factor specifications must be taken into consideration when interpreting the significance of computational results. (3 refs.)

Keywords:  Blood vessels  -  Finite element method  -  Hemodynamics  -  Lipids  -  Mathematical models  -  Navier Stokes equations  -  Nonlinear systems  -  Strain  -  Stresses

Secondary  Keywords:  Atherosclerosis  -  Fluid-structure interaction  -  Artery  -  Stenosis  -  Plaque cap rupture  -  Stroke  -  Heart  -  Blood flow

 


Dynamic behaviour of compliant towers in deep sea

Clauss, Gunther F. (Inst. of Land and Sea Transportation, Division of Ocean Engineering, Technical University of Berlin); Lee, June Young Source: Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, v 1, 2003, p 317-327

CODEN: PIOSEB

Conference: 22nd International Conference on Offshore Mechanics and Arctic Engineering; Offshore Technology Ocean Space Utilization, Jun 8-13 2003, Cancun, Mexico Sponsor: ASME;American Concrete Institute;ASCE;Associazione Italiana di Ingegneria Offshore e Marina;Brazilian Society of Naval Architects

Publisher: American Society of Mechanical Engineers

Abstract: For oil and gas production in deep water (&gt; 500m) compliant structures are designed. By dedicated reduction of stiffness and optimization of mass (including added mass contributions) the fundamental period is tuned to about 30s, which is well above the period range of significant wave energy. This paper presents the results of a comprehensive numerical analysis of the hydroelastic behaviour of compliant towers in deep water, investigating the dynamic response of a flexible structure in a given sea state. The numerical program system is based on ADINA with an integrated hydrodynamic module for wave/structure interaction. Nonlinear effects of viscous forces are considered using Morison's vector equation. In addition nonlinear characteristics of soil/structure interaction are also included according to API regulations. At first, for verification of the program system, the numerical results of a monotower are compared to analytical solutions obtained by modal analysis of the structure in regular and irregular seas. Based on the validated program a compliant tower installed in 503 m water in the Gulf of Mexico (Baldpate tower) is modeled in 3D, and the characteristic dynamic behavior is evaluated. Finally, the tower is exposed to a real "freak" wave (the 25.6m high New Year Wave which has been registered at the North Sea Draupner platform on January 1, 1995), and the associated loads and motions are evaluated. (19 refs.)

Keywords:  Ocean structures  -  Towers  -  Flexible structures  -  Stiffness  -  Structural analysis  -  Offshore oil well production  -  Water wave effects  -  Fluid structure interaction  -  Soil structure interactions  -  Computer programming  -  Structural optimization  -  Finite element method  -  Modal analysis

Secondary  Keywords:  Compliant towers  -  Harmonic excitations

 


Tensions and deformations of WC-Co cermets and 17-4 PH steel vacuum brazed joints

Nowacki, Jerzy (Institute of Materials Engineering, Technical University of Szczecin); Kawiak, Michal Source: Journal of Materials Processing Technology, v 143-144, n 1, Dec 20, 2003, p 294-299

ISSN: 0924-0136 CODEN: JMPTEF

Publisher: Elsevier Ltd

Abstract: Analysis of the properties of WC-Co cermets and precipitation hardening stainless steel of 17-4 PH type vacuum brazed joints has been presented. The joints are used in a large-dimension-spinning nozzle for polyethylene granulation in that considerable strength and ductility of the joints is required. The results of mechanical properties of the joint tests were a base for further numerical investigation. Shearing tests of the joints have been done on specimens based on the spinning nozzle brazed joint model. They have been executed using a special shearing test device. Numerical calculation of tensions and deformations of the joints have been made by means of the finite element method of the ADINA system. Influence of the geometrical parameters of the joints like the connection thickness as well as a fixed load on stresses and displacements of the joints have been analysed. Results of the experimental test were the base for identification and verification of the theoretical model parameters. The thickness of the joints has essential influence on the values of local stress and the significant influence on the joint rigidity. In case of the considered joints, the local stress differences have been even a few hundred percent, depending on a fixed load manner. © 2003 Elsevier Science B.V. All rights reserved. (10 refs.)

Keywords:  Cermets  -  Deformation  -  Stainless steel  -  Precipitation (chemical)  -  Hardening  -  Polyethylenes  -  Shearing  -  Compressive stress  -  Vacuum brazing  -  Finite element method

Secondary  Keywords:  Shearing tests


Three-dimensional transient finite element analysis of the laser enamelling process and moving heat source and phase change considerations

Nisar, A. (Manufacturing Division, Department of Mechanical Engineering, UMIST); Schmidt, M.J.J.; Sheikh, M.A.; Li, L. Source: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, v 217, n 6, 2003, p 753-764

ISSN: 0954-4054 CODEN: PIBMEU

Publisher: Professional Engineering Publishing Ltd.

Abstract: A finite element model has been developed to determine the temperature distribution generated during a high power diode laser (HPDL) tile grout sealing process. Because of the complexity of the process, which involves five different materials in a complicated geometrical arrangement, finite element (FE) numerical simulation using ADINA rather than an analytical system has been used to model the temperature profile. The analysis has involved simulation of the three-dimensional transient temperature field produced by a laser beam with constant power scanning over the glazed enamel surface at constant speeds. Latent heat effects due to melting and solidification of the glazed enamel have been taken into account in the FE model, thereby facilitating a more realistic thermal analysis. Experimental validation of the FE predicted temperature profile has also been presented. The results show that both the FE predicted temperatures and those determined experimentally are in close agreement with each other. The effect of varying process parameters on temperature profiles is discussed to facilitate prediction of optimized process parameters. (14 refs.)

Keywords:  High power lasers  -  Semiconductor lasers  -  Enameling  -  Temperature distribution  -  Transients  -  Laser beams  -  Thermoanalysis  -  Finite element method  -  Computer simulation

Secondary Keywords:  Transient temperature fields

 


Performance analysis for thermo-elastic-hydrodynamic lubrication of thrust bearing with pins and double layer system

Wu, Zhong-De (Sch. of Mechatronic Eng., Harbin Inst. of Technol.); Zhang, Hong; Ren, Zhong-Hai; Wang, Li-Qin; Qu, Da-Zhuang; Qi, Yu-Lin Source: Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology, v 35, n 1, January, 2003, p 81-84 Language: Chinese

ISSN: 0367-6234 CODEN: HPKYAY

Publisher: Harbin Institute of Technology

Abstract: The thermo-elastic-hydrodynamic lubrication performance of Three Gorges test thrust bearing with pins and double layer system for Alstom has been analyzed by the finite element methods. The lubrication calculation is programmed with the finite element methods. Together with the function of structural finite element program ADINAT and ADINA, a complete software of the thermo-elastic-hydrodynamic(TEHD) lubrication performance analysis is obtained, where the physical model includes lubricating oil film, thrust bearing, runner and thrust head. The thermo-elastic-deformation of thrust bearing and runner is analyzed with the program ADINA(T). The calculated results are compared with the measured ones in real operation. It shows that calculated characteristics are coincident with the experimental measurement, the pins and double layer system used in the test model has the advantage to control the thermal and elastic deformation of the pad, and the elasticity of the optimized pins further allows equalizing a significant part of the runner deformation. (4 refs.)

Keywords:  Thrust bearings  -  Lubrication  -  Control  -  Deformation  -  Elasticity  -  Finite element method  -  Elastohydrodynamics

Secondary  Keywords:  Runner and thrust head  -  Thermoelastichydridynamic  -  Double layer system  -  Lubricating oil film  -  Thermal and elastic deformation

 


Some aspects of modelling of metal forming processes

Gierzynska-Dolna, M. (Technical University of Czestochowa); Lacki, P. Source: Computers and Structures, v 81, n 8-11, May, 2003, p 605-613

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Science Ltd

Abstract: In the paper some numerical simulations of metal forming processes have been described. An attention has been paid to the problems occurring during the simulation processes. An approach to modelling of wear and friction has been presented. The possibility of assessing of a wear value by the basic wear parameters has been shown. The attention has also been paid to both sticking and sliding zones. Tools are very important during the designing process. Therefore, as an example, the possibility of analysis both the tools and a forging in an extrusion process has been shown. The numerical analysis has been performed using the ADINA System. © 2003 Elsevier Science Ltd. All rights reserved. (12 refs.)

Keywords:  Metal forming  -  Wear of materials  -  Friction  -  Metal extrusion  -  Deformation  -  Finite element method

Secondary  Keywords:  Contact surfaces

 


Nonlinear analysis of barge crush behavior and its relationship to impact resistant bridge design

Consolazio, Gary R. (Department of Civil Engineering, University of Florida); Cowan, David R. Source: Computers and Structures, v 81, n 8-11, May, 2003, p 547-557

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Science Ltd

Abstract: Bridge structures crossing navigable waterways must not only be designed to resist gravity, wind, and earthquake loads, but must also be capable of resisting ship and barge collision loads. Design specifications used both in the US and internationally employ empirical models of vessel crush behavior to produce codified procedures for computing equivalent static design loads due to vessel impact. In this paper, the ADINA finite element code is used to compute force-deformation relationships for several hopper barge crushing scenarios. Results obtained from the nonlinear finite element crush analyses are then compared to empirical crush models found in bridge design specifications. © 2003 Elsevier Science Ltd. All rights reserved. (13 refs.)

Keywords:  Structural design  -  Bridges  -  Impact resistance  -  Structural loads  -  Deformation  -  Finite element method

Secondary Keywords:  Barge impact

 


Design analysis of the support structure stressed by large superconducting coils for a plasma fusion experiment

Jaksic, N. (Max-Planck-Inst. for Plasmaphysics, EURATOM Association); Simon-Weidner, J. Source: Computers and Structures, v 81, n 8-11, May, 2003, p 697-714

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Science Ltd

Abstract: A long term task of design analysis for a prototype machine, used in plasma fusion research, is described in this paper. The core part of each plasma fusion experiment, the superconducting coils and their surrounding structure, are under consideration here. Specificity and complexity of the task are discussed as well. The R and D activities on the structural system of the experimental device were done in a time spread of over 10 years. For the numerical simulation and analysis of the phenomena inside the structure, the ADINA code was chosen right from start. This decision was mainly guided considering the efficiency of ADINA in solving nonlinear problems with a large number of degrees of freedom. The ADINA code is still most commonly used for numerical simulations on the current project which is presently in the state of manufacturing. © 2003 Elsevier Science Ltd. All rights reserved. (20 refs.)

Keywords:  Superconducting materials  -  Plasma applications  -  Fusion reactions  -  Stress analysis  -  Structural design  -  Finite element method  -  Problem solving  -  Computer simulation

Secondary  Keywords:  Plasma fusion

 

Nonlinear finite element analysis of prestressed concrete members using ADINA

Kawakami, Makoto (Kozo Keikaku Engineering Inc.); Ito, Tadahiko Source: Computers and Structures, v 81, n 8-11, May, 2003, p 727-734

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Science Ltd

Abstract: A prestressed concrete (PC) column and a precast segmental PC beam are analyzed using ADINA. Two dimensional finite element model is employed with material nonlinearities (concrete cracking/crushing and rebar plasticity) and geometrical nonlinearities (large displacement and contact/separation between the segments). The load-displacement relationship, the concrete cracking/crushing process, the load-strain relationship, and the gap opening/closing are in good agreement with those in the tests. All rights reserved. (6 refs.)

Keywords:  Prestressed concrete  -  Columns (structural)  -  Beams and girders  -  Structural loads  -  Strain  -  Cracks  -  Finite element method

Secondary Keywords:  Material nonlinearities

 



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