ADINA Publications

Page 20

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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Tooth–implant connection: some biomechanical aspects based on finite element analyses

G. Menicucci1, M. Mozzati1, M. Lorenzetti1, G. Preti1, A. Mossolov2

1Prosthodontic Department, School of Dentistry, University of Turin, Turin.
2ITERA S.r.l., Turin, Italy

Clin Oral Implants Res., 13(3):334-41, 2002

Abstract: This study investigated, with the use of two- and three-dimensional finite element  analysis, the peri-implant stress that occurred during loading of a tooth that was rigidly connected to a distally placed implant. A fixed bond between the bone and the implant was assumed, while the periodontal ligament was represented by means of three-dimensional nonlinear visco-elastic spring elements. Two different loading conditions were compared in the study: i) an axially directed static load of 50 kg that was applied to the tooth for 10 s, and ii) a transitional load of 50 kg that was applied for 5 milliseconds. Load duration appeared to have a greater influence than load intensity on the stress distribution in the bone around an implant and a rigidly connected tooth. Static load is, therefore, potentially more harmful for peri-implant bone than transitional load. The periodontal ligament seems to play a key role in the stress distribution between a tooth and a rigidly connected implant.

 

Shear stress distributions on the membrane of endothelial cells using 3-D computational modeling with fluid-structure interactions

Tang, Dalin (Mathematical Sciences Dept., Worcester Polytechnic Institute); Yang, Chun; Liu, Shu Q. Source: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 1, 2002, p 375-376

ISSN: 0589-1019 CODEN: CEMBAD

Conference: Proceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS), Oct 23-26 2002, Houston, TX, United States

Publisher: Institute of Electrical and Electronics Engineers Inc.

Abstract: Fluid shear stress may play an important role in regulating cell activities and motility of growth factors in artery remodeling, atherosclerosis and re-stenosis process. 3-D computational models based on multi-cell experimental model are introduced and solved to quantify shear stress distributions on cell surfaces under physiological setting. Combined with experimental data, relationship between fluid shear stress and endothelial cell activities can be established. Cell geometry and membrane mechanical properties affect micro flow environment leading to considerable changes in shear stress distributions and various cell activities such as cell migration and activation of cell migration signaling mechanisms. (4 refs.)

Keywords:  Cell membranes  -  Computer simulation  -  Mathematical models  -  Computational fluid dynamics  -  Shear stress  -  Fluid structure interaction  -  Stress concentration  -  Navier Stokes equations  -  Finite element method  -  Structure (composition)  -  Growth kinetics  -  Three dimensional

Secondary  Keywords:  Endothelial cells  -  Shear stress distribution  -  Microflow  -  Software Package ADINA

 


Single cell micromanipulation using magnetic beads: A computational model

Karcher, H. (Department of Mechanical Engineering, Division of Biological Engineering, Massachusetts Institute of Technol.); Kaazempur-Mofrad, M.R.; Kamm, R.D. Source: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 1, 2002, p 379-380

ISSN: 0589-1019 CODEN: CEMBAD

Conference: Proceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS), Oct 23-26 2002, Houston, TX, United States

Publisher: Institute of Electrical and Electronics Engineers Inc.

Abstract: A computational finite element model (FEM) 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. Correlation of the computational model and experimental findings promises to shed light on the mechanical properties of the cell and their variation under different mechanical/biological stimulations. (5 refs.)

Keywords:  Cytology  -  Cells  -  Finite element method  -  Computational methods  -  Mathematical models  -  Boundary conditions

Secondary  Keywords:  Computational finite element model  -  Single cell micromanipulation  -  Magnetic beads  -  Magnetocytommetry  -  Software Package ADINA  -  Stress field

 

 

Stability of Elastomeric Isolation Bearings: Experimental Study

I. Buckle1; S. Nagarajaiah2; and K. Ferrell3

1 Dept. of Civil Engineering, Univ. of Nevada, Reno, NV 89557
2 Dept. of Civil Engineering, Rice Univ. Houston, TX 77005
3 Dept. of Transportation, Jefferson City, MO 65102

Journal of Structural Engineering, 128(1):3-11, 2002

Abstract: Elastomeric isolation bearings are required to be stable at high shear strains, which occur during strong earthquakes. Hence, rigorous determination of the critical axial load during design is important. Currently, the critical load is determined using the small displacement Haringx theory and modified to account for large shear strains by an approximate correction factor. The objective of this study is to experimentally determine the effect of horizontal displacement or shear strain on critical load and to study the validity of the approximate correction factor. Experiments were conducted on a series of elastomeric bearings with low shape factors. Test procedure and test results are presented in detail. It is shown that the critical load decreases with increasing horizontal displacement or shear strain. It is also shown that substantial critical load capacity exists at a horizontal displacement equal to the width of the bearing and is not zero, as predicted by the correction factor. It is further shown that the approximate formula is not conservative at smaller displacements and overly conservative at larger displacements. The critical loads obtained from experiments are compared with results from finite element analyses and nonlinear analytical solutions; the comparisons indicate that the effect of large horizontal displacements on the critical load can be reliably predicted.

Keywords: Seismic isolation — Stability — Experimentation — Shear strain — Axial loads —  Critical loads

 

 

Seismic Analysis Of Hollow Buttress Gravity Dams

P Brindisi1, A De Sortis2, G Di Lemma1, G Orsini2

1 Servizio Nazionale Dighe, Via Curtatone 3, 00185 Roma, IT
2 Servizio Sismico Nazionale, Via Curtatone 3, 00185 Roma, IT

Proc. 12th European Conference on Earthquake Engineering, 2002

A typology of gravity dams rather common in Italy has been obtained by the arrangement of buttress consisting of hollow triangular elements. Several studies devoted to this typology are available in literature, especially for the effects of the thermal and permanent loading. A characteristic observable on various elements of the same dams and on various different dams is the presence of cracks with rather typical width, extension and shape. The paper has the aim of: (i) studying the typical crack development (on the basis of the available information about the materials, the construction phases, the observed variation of temperature and water level) to reproduce as far as possible the behaviour under permanent loading; (ii) modelling the seismic behaviour with a pushover analysis, taking into account the cracked condition of the structure; (iii) judging the seismic behaviour on the basis of the available knowledge about the seismic hazard in Italy. Starting from the past studies and from some direct observations, a finite element model of a buttress have been developed to furnish an interpretation of the typical cracked condition. The results of this model have been assumed as the initial state of the subsequent seismic analyses. In this phase, the non linear behaviour of the structure material has been considered. The analyses showed that the maximum horizontal seismic force carried by the buttress is greater than the maximum load expected on the basis of probabilistic seismic hazard spectra. Furthermore it seems that the seismic capacity of the analysed buttress is not remarkably affected by the typical observable cracks.

Keywords: Dams — Construction phases — Pushover analysis — Seismic behaviour

 

 


Thermofluid analysis of free surface liquid divertor in tokamak fusion reactor

Kurihara, Ryoichi (Japan Atomic Energy Res. Institute) Source: Fusion Engineering and Design, v 61-62, November, 2002, p 209-216

ISSN: 0920-3796 CODEN: FEDEEE

Publisher: Elsevier Science Ltd

Abstract: To attain high fusion power density, the divertor must suffer a high heat flux from the fusion plasma. It is very difficult to remove the high heat flux from the fusion plasma more than 20 MW/m2 using the only solid divertor plate due to the severe mechanical condition such as thermal stress and crack growth. Therefore, the concept of a liquid divertor is proposed to remove the high heat flux and neutron flux from the plasma by liquid films flowing on a solid wall. Feasibility study on the liquid divertor is being examined what kind of necessary condition should be satisfied if it was applied to the tokamak fusion reactor. There are many uncertain physics and techniques to apply the liquid divertor to the tokamak fusion reactor. This paper mainly descries a preliminary thermofluid analysis of a free surface liquid, made of FLiBe molten salt, flow suffering the high heat flux using the finite element analysis code ADINA-F. To realize the liquid divertor, two techniques of thermal hydraulics promotion using a secondary flow and liquid-solid multi-phase flow are proposed in this paper. © 2002 Elsevier Science B.V. All rights reserved. (9 refs.)

Keywords:  Fusion reactor divertors  -  Fusion reactions  -  Tokamak devices  -  Heat flux  -  Thermal stress  -  Crack propagation  -  Hydraulics  -  Thermal conductivity  -  Finite element method

Secondary  Keywords:  Secondary flow

 


Nonlinear strength analysis of multiplanar tubular joints between I-beam and hollow circular sections

Wang, Yuanqing (Dept. of Civil Eng., Tsinghua Univ.); Zeng, Wenping; He, Dongzhe Source: Qinghua Daxue Xuebao/Journal of Tsinghua University, v 42, n SUPPL., July, 2002, p 101-104 Language: Chinese

ISSN: 1000-0054 CODEN: QDXKE8

Publisher: Press of Tsinghua University

Abstract: New steel structures are being desinged with circular tubes as the chords and square tubes as the braces. However, the joint stress in this structure is very complex so numerical analysis of the joint loading capacity is needed to design the structure. Nonlinear finite element analysis (FEA) was used to analyze the multiplanar tubular joint between I-beam and hollow circular sections. A four-node general quadrilateral shell element was used for the nonlinear geometric and material analyses in the finite element model with an automatic incrementing algorithm in the iterative computation. The analysis was completed using ADINA. Linear regression of the results from the nonlinear analyses of a large number of examples was used to develop formulas for calculating the joint loading capacity for axial loads and for out-of-plane moments which can be used for engineering design. The results have been successfully used in the design of the MEGA Exhibition Center in Singapore. (8 refs.)

Keywords:  Tubular steel structures  -  Joints (structural components)  -  Strength of materials  -  Finite element method  -  Regression analysis  -  Numerical analysis

Secondary  Keywords:  Multiplanar tubular joint  -  Hollow circular sections  -  Four node shell element

 

 

Tooth–implant connection: some biomechanical aspects based on finite element analyses

G. Menicucci1, A. Mossolov2, M. Mozzati1, M. Lorenzetti1, and G. Preti1

1 Prosthodontic Department, School of Dentistry, University of Turin, Turin
2 ITERA S.r.l., Turin, Italy

Clin. Oral Impl. Res, 13:334–341, 2002

Abstract: This study investigated, with the use of two- and three-dimensional finite element analysis, the peri-implant stress that occurred during loading of a tooth that was rigidly connected to a distally placed implant. A fixed bond between the bone and the implant was assumed, while the periodontal ligament was represented by means of three-dimensional nonlinear visco-elastic spring elements. Two different loading conditions were compared in the study: i) an axially directed static load of 50 kg that was applied to the tooth for 10 s, and ii) a transitional load of 50 kg that was applied for 5 milliseconds. Load duration appeared to have a greater influence than load intensity on the stress distribution in the bone around an implant and a rigidly connected tooth. Static load is, therefore, potentially more harmful for peri-implant bone than transitional load. The periodontal ligament seems to play a key role in the stress distribution between a tooth and a rigidly connected implant.

 

 

Neutrophil transit times through pulmonary capillaries: The effects of capillary geometry and fMLP-stimulation

Mark Bathe,1 Atsushi Shirai,1 Claire M. Doerschuk,2 and Roger D. Kamm1

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

2Department of Pediatrics, Rainbow Babies and Children’s Hospital and Case Western Reserve University, Cleveland, Ohio 44106 USA

Biophysical Journal, Vol. 83, 1917–1933, 2002

Abstract: The deformations of neutrophils as they pass through the pulmonary microcirculation affect their transit time, their tendency to contact and interact with the endothelial surface, and potentially their degree of activation. Here we model the cell as a viscoelastic Maxwell material bounded by constant surface tension and simulate indentation experiments to quantify the effects of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-stimulation on its mechanical properties (elastic shear modulus and viscosity). We then simulate neutrophil transit through individual pulmonary capillary segments to determine the relative effects of capillary geometry and fMLP-stimulation on transit time. Indentation results indicate that neutrophil viscosity and shear modulus increase by factors of 3.4, for 10-9 M fMLP, and 7.3, for 10-6 M fMLP, over nonstimulated cell values, determined to be 30.8 Pa·s and 185 Pa, respectively. Capillary flow results indicate that capillary entrance radius of curvature has a significant effect on cell transit time, in addition to minimum capillary radius and neutrophil stimulation level. The relative effects of capillary geometry and fMLP on neutrophil transit time are presented as a simple dimensionless expression and their physiological significance is discussed.

 

 

The Male Predisposition to Pharyngeal Collapse Importance of Airway Length

Atul Malhotra, Yaqi Huang, Robert B. Fogel, Giora Pillar, Jill K. Edwards, Ron Kikinis, Stephen H. Loring, and David P. White

Division of Sleep Medicine and Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women’s Hospital, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts

Am J Respir Crit Care Med, Vol 166. pp 1388–1395, 2002

Abstract: Obstructive sleep apnea is an important disorder because of both its prevalence and its cardiovascular and neurocognitive sequelae. Despite the fact that male sex is amajor risk factor for this disorder, the mechanisms underlying this predisposition are unclear. To understand the pathophysiologic basis of the male predisposition for pharyngeal collapse, we performed a detailed analysis of the anatomic and physiologic features of the upper airway in a cohort of normal and near-normal subjects (equal number of men and women). Although no important physiologic (genioglossal electromyogram, airflow resistance) differences were observed between sexes, a number of anatomic differences were apparent. The pharyngeal airway length was substantially longer in men compared with women. There was also an increased cross-sectional area of  the soft palate and an increased airway volume in men compared with women. Using signal-averaged anatomic data from male and female subjects, we developed representative male and female finite element airway models. This model demonstrated the male airway to be substantially more collapsible than the female airway, solely on the basis of anatomic differences. This study suggests that the male predisposition to pharyngeal collapse is anatomically based, primarily as the result of an increased length of vulnerable airway as well as increased soft palate size.

Keywords: apnea - finite element – length – sleep - upper airway

 


Numerical modelling of carbon/epoxy laminated plate impact damage

Rilo, Nuno Ferreira (Centro de Engenharia Mecanica, Universidade de Coimbra); Ferreira, Luis Manuel Silva; Cirne, Jose Maria Osorio Sousa; Leal, Rogerio Augusto Da Costa Pereira Source: Key Engineering Materials, v 230-232, 2002, p 533-536

ISSN: 1013-9826 CODEN: KEMAEY

Conference: Advanced Materials Forum I: Proceedings of the 1st International Materials Symposium, Apr 9-11 2001, Coimbra, Portugal

Publisher: Trans Tech Publications Ltd

Abstract: Numerical simulation of static indentation and lateral impact tests of carbon/epoxy laminated composite plates, using ADINA finite element system is presented. The geometry, loading and boundary conditions used in simulation were determined by the drop test Rosand system that will be used to compare numerical results. Unidirectional and several 0/90 ply orientations stacking sequences carbon/epoxy plates were used in order to study the influence of thickness and ply orientation on the deformation and failure of the plates. Linear and nonlinear static response analyses were considered in the simulations of displacements and the extent and nature of damage. In the development of these studies, combined use of finite element analysis and impact testing is necessary to assess the damage tolerance of composite components. Afterwards, by parametric studies, it will be possible to study in a systematic way the effects of thickness, shape, ply orientations and duration of impact on deformation and failure of the plates. (6 refs.)

Keywords:  Plates (structural components)  -  Laminated composites  -  Carbon  -  Impact testing  -  Indentation  -  Deformation  -  Failure (mechanical)  -  Delamination  -  Finite element method  -  Boundary conditions  -  Computer simulation

Secondary  Keywords:  Damage

 


Static behavior of piezoelectric actuated beams

Yocum, Matthew (Department of Aerospace Engineering, Technion, IIT); Abramovich, Haim Source: Computers and Structures, v 80, n 23, September, 2002, p 1797-1808

ISSN: 0045-7949 CODEN: CMSTCJ

Publisher: Elsevier Science Ltd

Abstract: This study details the static experimental behavior of a cantilever beam actuated using piezoceramic patches. Results of static experiments are extremely rare in the literature; current applications are focusing mostly on a dynamic environment. Experiments were performed by running a DC current through the piezoelectric patches, and several important points were discovered to do proper testing. The material must be prepared by adding a DC voltage at or higher than the proposed test voltage to minimize drift during the test. Experimental results were compared with the finite element code ADINA predictions using its built-in piezoelectric modeling routine, with modeling in good agreement if the nonlinear electromechanical coupling is used. © 2002 Elsevier Science Ltd. All rights reserved. (21 refs.)

Keywords:  Cantilever beams  -  Piezoelectricity  -  Electric currents  -  Electric potential  -  Finite element method  -  Mathematical models

Secondary  Keywords:  Piezoceramic patches

 


Prediction of temperature and stress fields in beryllium ring during electron beam welding by finite element analysis

Dong, Ping (China Acad. of Eng. Phys.); Chen, Yu-Ze; Zou, Jue-Sheng Source: Yuanzineng Kexue Jishu/Atomic Energy Science and Technology, v 36, n 3, May, 2002, p 209-213 Language: Chinese

ISSN: 1000-6931 CODEN: YKJIEZ

Publisher: Atomic Energy Publishing House

Abstract: The temperature and stress fields in beryllium ring are analyzed ADINA/ADINAT software during electron beam welding. The result shows that the highest temperature at the outer surface reaches 2734°C, while the highest temperature at the inner surface is only 378°C, which is located at the side of out-opening of beryllium ring. After welding, residual stress is considerable large and complexity within 2.0 mm from the weld line and residual stress reaches the largest at the weld toe. For the structure difference between in-opening and out-opening beryllium ring, residual stress at the in-opening beryllium ring is not as same as that at the out-opening beryllium ring. (3 refs.)

Keywords:  Electron beam welding  -  Welds  -  Temperature distribution  -  Finite element method  -  Computer simulation  -  Beryllium

Secondary  Keywords:  Stress field  -  Temperature field  -  Finite element analysis

 


Numerical modelling of shear bands by element bands

Wang, X. (ADINA R and D Inc.); Chan, D.; Morgenstern, N. Source: International Journal for Numerical Methods in Engineering, v 54, n 8, Jul 20, 2002, p 1131-1159

ISSN: 0029-5981 CODEN: IJNMBH

Abstract: It is presently a concern and challenge to numerically model shear band localization. Many numerical methods have been developed to take into account the strain and displacement discontinuities across a shear band. In this paper, a contact band element method is proposed to model the shear band with a finite thickness under large shear deformation. The shear band elements, alternatively called contact band elements, are continuously updated based on their current configurations to prevent the large distortions of conventional finite elements and maintain realistic shear band configurations. The contact band element method, with a technique for the special shear band element, consists of the schemes to keep the shear band elements in good shapes, handle the band overlapping, kinking and separation problems. A few examples have shown that the contact band element method is a very efficient way to model the shear bands under large shear deformation. Copyright © 2002 John Wiley and Sons, Ltd. (29 refs.)

Keywords:  Mechanical engineering  -  Shear deformation  -  Strain  -  Finite element method  -  Numerical methods

Secondary  Keywords:  Shear band localization

 


Viscoelastic micromechanical modeling of free edge and time effects in glass fiber/epoxy cross-ply laminates

Ellyin, Fernand (Department of Mechanical Engineering, University of Alberta); Xia, Zihui; Chen, Yu Source: Composites - Part A: Applied Science and Manufacturing, v 33, n 3, March, 2002, p 399-409

ISSN: 1359-835X CODEN: CASMFJ

Publisher: Elsevier Science Ltd

Abstract: A viscoelastic finite element analysis has been carried out to investigate the free edge and time effects in a [0/90]<sub]ns</sub] glass fiber/epoxy cross-ply laminate, subjected to mechanical loads. The analysis is based on a three-dimensional micromechanical model that predicts the stress/strain field at the fiber and matrix levels near the free edge surface of the cross-ply laminate. The epoxy matrix is represented by a nonlinear viscoelastic constitutive model. In addition, two different damage criteria for the matrix cracking and interface debonding have been introduced into the model, which were incorporated into the finite element analysis program, adina, through the user-defined subroutine. Damage initiation as well as damage growth in the cross-ply laminate is predicted by the present model. It is found that the edge effect is more dominant in the damage initiation process and its influence on the global properties of cross-ply laminate, is not significant. Under a constant load, it is possible for the damage to grow further due to the viscosity of the matrix and the stress/strain redistribution in the cross-ply laminate. © 2002 Elsevier Science Ltd. All rights reserved.

Keywords:  Nonmetallic matrix composites  -  Laminated composites  -  Fiber reinforced materials  -  Composite micromechanics  -  Viscoelasticity  -  Finite element method

Secondary Keywords:  Polymer-matrix composites (PMC)

 


Nonlinear elastostatics of a toroidal shell subject to local loading

Zhang, Y.M. (Department of Mechanical Engineering, University of Ottawa); Redekop, D. Source: American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, v 430, Pressure Vessel and Piping Design and Analysis - 2001, 2001, p 119-124

ISSN: 0277-027X CODEN: AMPPD5

Conference: 2001 ASME Pressure Vessels and Piping Conference, Jul 22-26 2001, Atlanta, GA, United States Sponsor: Pressure Vessels and Piping Division, ASME

Publisher: American Society of Mechanical Engineers

Abstract: The nonlinear elastostatics problem of a toroidal shell subjected to local loading is studied using an analytical and a numerical method. Major effects are assumed local, and thus only a semi-torus (180&deg; circumferential arc) is modelled. Loadings both at the extrados and intrados of the torus are considered. The Sanders shell theory serves as the basis of the analytical solution. An incremental approach is proposed in which the Frechet differential is employed to get the tangent stiffness, and the differential quadrature method is used to determine refinements in the displacements. The commercial ADINA finite element program is used to obain a purely numerical solution. Results in the linear range are presented, and conclusions are drawn. (12 refs.)

Keywords:  Shells (structures)  -  Elasticity  -  Finite difference method  -  Finite element method  -  Loading  -  Numerical methods  -  Rotation  -  Structural design

Secondary  Keywords:  Toroidal shells  -  Differential quadrature methods

 


Three-dimensional finite element analysis of welding stress-strain in a girth welded pipe

Dong, Junhui (Inner Mongolia Polytech. Univ.); Huo, Lixing; Zhang, Yufeng Source: Jixie Gongcheng Xuebao/Chinese Journal of Mechanical Engineering, v 37, n 12, December, 2001, p 86-90 Language: Chinese

ISSN: 0577-6686 CODEN: CHHKA2

Publisher: Editorial Office of Chinese Journal of Mechanical Engineering

Abstract: Three-dimensional finite element analysis of welding stress-strain in a girth-butt welded pipe is presented, with a nonlinear FE code ADINA. The pipe material is low-carbon steel. The thermo-physical and mechanical properties of material depend on temperature. The element birth facility in ADINA is used to model the continuous deposition of filler material into the groove. In the girth-welded pipes, axial residual stresses in the weld vicinity are tensile on inner surface and compressive on outer surface. Hoop residual stresses in the weld vicinity are tensile in both inner and outer surfaces. The calculated results are in agreement with the experimental measurements. It is show that FEM can predict the welding residual stresses in girth-butt welded pipes effectively. (6 refs.)

Keywords:  Butt welding  -  Pipe joints  -  Residual stresses  -  Finite element method  -  Three dimensional  -  Mathematical models  -  Welds

Secondary Keywords:  Girth welded pipes  -  Temperature field  -  Low carbon steel

 


Fracture mechanics evaluation of a crack generated in SiC/SiC composite first wall

Kurihara, Ryoichi (Fusion Reactor System Laboratory, Naka Fusion Research Establishment, Japan Atomic Energy Research Inst.); Ueda, Shuzo; Nishio, Satoshi; Seki, Yasushi Source: Fusion Engineering and Design, v 54, n 3-4, April, 2001, p 465-471

ISSN: 0920-3796 CODEN: FEDEEE

Publisher: Elsevier Science Ltd

Abstract: The finite element analysis was carried out for the blanket first wall made of SiC/SiC composite material for the future Tokamak fusion power reactor DREAM, which is conceptually designed in the Japan Atomic Energy Research Institute. Bending deflection and stress distribution were analyzed when the thermal expansion was constrained at the edge of the first wall. Preliminary fracture mechanics evaluation was carried out, assuming a crack in the first wall, by the finite element code ADINA. The result showed that it is necessary to find a new device for releasing thermal expansion in the design of the first wall. Effect of the fiber bridging on the crack arrest was studied in the first wall structure made of SiC/SiC composite material. © 2001 Elsevier Science B.V. (8 refs.)

Keywords:  Tokamak devices  -  Bending (deformation)  -  Breeding blankets  -  Composite materials  -  Computer software  -  Cooling  -  Finite element method  -  Fracture mechanics  -  Helium  -  Microcracks  -  Silicon carbide  -  Stress analysis  -  Stress concentration  -  Thermal expansion

Secondary Keywords:  Software package ADINA

 


Strain distribution analysis of welded lap joints with different matching by moire interferometry

Cheng, Jun (Tongji University); Fang, Ruhua Source: Proceedings of SPIE - The International Society for Optical Engineering, v 4537, 2001, p 186-189

ISSN: 0277-786X CODEN: PSISDG

Conference: 3th Conference on Experimental Mechanics, Oct 15-17 2001, Beijing Sponsor: SPIE

Publisher: The International Society for Optical Engineering

Abstract: The welded lap joints with different matching are analyzed by Moire interferometry. The strain distribution with lower matching in front weld metal are higher than that with higher matching in front weld metal. The strain distribution with different matching along force parallel direction are the same. The strain distributions with lower matching in base metal are lower than that with higher matching in base metal. The strain distribution of different matching along the force parallel direction has little difference. The V field fringe deformation of different matching in base metal and weld metal are the same. The U field fringe deformations are different. The fringes with lower matching in weld metal are more crowded than base metal. The fringe with higher matching is more concentrated in the middle. The strain distributions of higher matching in weld metal are lower. The finite element was used to prove the experiment results in this paper. This result has engineering meaning to improve the mechanical properties of the welded lap joint.

Keywords:  Strain  -  Welds  -  Interferometry  -  Deformation  -  Mathematical models  -  Finite element method  -  Stress concentration

Secondary  Keywords:  Strain distribution analysis  -  Welded lap joints  -  Moire interferometry  -  Software Package ADINA


2-D finite element analysis of singly curved prestressed concrete shells

Rajagopalan, N. (Department of Civil Engineering, Indian Institute of Technol. Madras); Ragunath, S.S.; Ramamurthy, K. Source: Journal of Structural Engineering (Madras), v 28, n 3, October/December, 2001, p 141-146

ISSN: 0970-0137 CODEN: JSENEI

Publisher: Structural Engineering Research Centre

Abstract: Singly curved or doubly curved shells, most commonly used in large span structures, are analyzed using flat plate/shell/plate-shell. Depending on their structural actions and stresses generated, sometimes they are also prestressed. If the prestressing is in a direction where the curvature of the shell is negligible or zero, the shell structure could be analyzed using surface elements (e.g. cylindrical shells prestressed longitudinally). If the prestressing is in a direction where the structural element has a curvature (e.g. cylindrical shells prestressed along the curved axis), it introduces circumferential forces and hence may introduce stress gradients in direction normal to the curved axis viz., in the thickness direction, which cannot be idealised using surface elements. Analysis of such shells using ADINA code is presented in this paper. The results show that for a prestressing cable placed somewhere within the thickness of the shell and sufficiently away from the boundaries, the variation of normal radial stress changes from tension above the cable profile to compression below the cable profile, clearly indicating the existence of radial tension. The magnitude of the radial tension is influenced by the parameters like radius, semi-central angle, rise of the shell and thickness. The radial stress varies inversely with radius and directly with rise, while change in thickness and semi-central angle do not affect its behaviour at the apex. (10 refs.)

 



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