Publications

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

  

  


To Enrich Life
(Sample pages here)

To Download — Second Edition of the Book "Finite Element Procedures" (6th printing)

You are welcome to download the second edition of the book, 6th printing, however, please note that the book is copyrighted and should only be used in the same manner as a purchased hard-copy of the book.

Improved versions will be made available here, from time to time, as the 7th printing, and so on.

"Finite Element Procedures", 2nd Edition (.pdf)

Solutions to exercises in the book "Finite Element Procedures", 2nd Edition, 2014 are given in this manual (.pdf)

The Chinese translation of the 2nd edition is also available: Vol. 1 Vol. 2


Following are more than 700 publications — that we know of — with reference to the use of ADINA. Since there are numerous papers published in renowned journals, we can only give here a selection. 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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Numerical analysis of thermal stress-deformation in concrete surrounding FRP bars in hot region

Zaidi, A.1, Masmoudi, R.2, Bouhicha, M.1

1 Laboratory of Materials and Structure Rehabilitation (SREML), Laghouat University, Laghouat 03000, Algeria

2 Civil Engineering Department, Sherbrooke University, QC J1K 2R1, Canada

Construction and Building Materials: Volume 38, January 2013, Pages 204-213

Abstract: The transverse thermal incompatibility between fiber reinforced polymer (FRP) bar and concrete generates radial pressure, at FRP bar/concrete interface, that may cause splitting cracks within the concrete under temperature increase and, ultimately, failure of the concrete cover. This paper presents a non-linear finite element analysis using ADINA Software to investigate transverse thermal deformations and stresses through concrete cover surrounding FRP bars under high temperatures up to +60 °C varying the ratio of concrete cover thickness to FRP bar diameter (c/d b ). This investigation allows to determine the temperature increase (ΔT cr ) producing the first radial crack in concrete at the interface and the temperature increase (ΔT sp ) producing splitting failure of the concrete cover. Comparisons between numerical, analytical, and experimental results are presented.

Keywords: Concrete cover - Deformation - Finite element - FRP bar - High temperature - Splitting cracks

 

ElastoHydroDynamic lubricated cylindrical joints for rigid-flexible multibody dynamics

Tian, Q.1, Sun, Y.1, Liu, C.1, Hu, H.1, Flores, P.2

1 Key Laboratory of Dynamics and Control of Flight Vehicle, School of Aerospace Engineering, Ministry of Education (MOE), Beijing 100081, China

2 Department of Mechanical Engineering, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal

Computers and Structures: Volume 114-115, January 2013, Pages 106-120

Abstract: A new methodology is proposed for the dynamic analysis of rigid-flexible multibody systems with ElastoHydroDynamic (EHD) lubricated cylindrical joints. The EHD lubricated cylindrical joint is formulated by the Natural Coordinate Formulation (NCF) and the 20-node hexahedral elements of Absolute Nodal Coordinate Formulation (ANCF), with the lubricant pressure determined through the resolution of the Reynolds' equation employing the finite difference method. The main outcomes are validated with those obtained by using the commercial software ADINA. It is shown that the bearing flexibility plays a significant role in the system responses, extends the lubricant distribution space and, consequently, reduces the lubricant pressure.

Keywords: Absolute Nodal Coordinate Formulation (ANCF) - ElastoHydroDynamic (EHD) - Lubricated cylindrical joint - Multibody dynamics - Natural Coordinate Formulation (NCF)

 

Modeling sudden ice shedding from conductor bundles

Kollar, L.E., Farzaneh, M.

International Research Center on Atmospheric Icing and Power Network Engineering (CENGIVRE), University of Quebec at Chicoutimi, Chicoutimi, QC G7H 2B1, Canada

IEEE Transactions on Power Delivery: Volume 28, Issue 2, 2013, Article number 6387343, Pages 604-611

Abstract: Sudden ice shedding from conductor bundles was modeled numerically and experimentally by improving the approaches proposed formerly for a single cable. The experimental study was carried out on a small-scale laboratory model of one span of a twin bundle. A numerical model of the experimental setup was developed using the commercial finite-element software ADINA. This model was validated by simulating: 1) the vertical cable vibration during former load shedding tests on a full-scale line of single conductors; 2) the bundle rotation on a full-scale twin bundle during former static torsional tests; and 3) the vertical cable vibration and bundle rotation at midspan during the present load shedding tests on a small-scale twin bundle. The coincidence of calculated and measured tendencies justified the applicability of the numerical model to simulate the vibration following ice shedding from bundled conductors in most cases. The model was finally applied to simulate sudden ice shedding from a full-scale span with a twin bundle. Simulation results showed that the application of spacers reduces the cable jump height during this vibration; however, a higher number of spacers in the same span does not decrease the angle of bundle rotation.

Keywords: Bundle rotation - cable vibration - ice shedding - numerical modeling - small-scale experiment

 

Computational analysis of high frequency fluid-structure interactions in constricted flow

Salman, H.E., Sert, C., Yazicioglu, Y.

Middle East Technical University, Department of Mechanical Engineering, Ankara, Turkey

Computers and Structures: Volume 122, 2013, Pages 145-154

Abstract: Constricted flow in a thin cylindrical shell with an idealized blunt constriction is modeled using ADINA. Highly disturbed recirculation region is observed at the constriction exit where pressure fluctuations and consequential vessel wall vibrations display broadband spectral content over a range of several hundred Hz. Maximum dynamic pressure and vibration amplitudes are observed around the reattachment point and they gradually decrease along downstream of flow. Results obtained by numerical simulations are compared with relevant studies in the literature and are in good agreement in terms of general spectral behavior. However, the amplitudes were significantly lower as compared to experimental results.

Keywords: Blood flow simulation - Constricted flow - Fluid structure interaction - Stenosis - Vessel wall vibration

 

Gust response of a flexible typical section via high- and (tuned) low-fidelity simulations

Sucipto, T.1, Berci, M.2, Krier, J.1

1 IBK Technology, Rehdorfer Strasse, 90431 Nuremberg, Germany

2 University of Leeds, Woodhouse Lane, LS29JT Leeds, United Kingdom

Computers and Structures: Volume 122, 2013, Pages 202-216

Abstract: The gust response of a flexible typical section is investigated in term of both high- and low-fidelity simulations, in order to assess the suitability of the two approaches in the preliminary Multidisciplinary Design and Optimisation (MDO) of flexible wing aerofoils. A vertical wind gust acts as the aerodynamic perturbation to the static equilibrium of the typical section, the dynamic response of which is formulated as a fluid-structure interaction (FSI) problem in the subsonic regime and computed for a "1-COS" gust profile having different intensities. The low-fidelity response is calculated using a (tuned) theoretical model, whereas the high-fidelity one is obtained using the commercial tool ADINA, where both k - ω and k - ∈ turbulence models are employed. The effects of the physical differences between the high-and low-fidelity models are identified in the aerofoil response for the case of either weak or strong travelling gust, where the influence of the aerofoil on the latter is accounted for in the high-fidelity simulations only. Both thin and thick aerofoils are considered and the low-fidelity results agree well with the high-fidelity ones for the case of weak gust and attached aerodynamic flow, whereas the opposite is true for the case of strong gust and separated aerodynamic flow.

Keywords: Aeroelasticity - CFD - Flexible aerofoil - FSI - Gust response - Multifidelity

 

Evaluation of buckling in prestressed composite truss girder using ADINA structure analysis

Kim, E.S., Kim, J.H.

National Forensic Service, South Korea

Transactions of the Korean Society of Mechanical Engineers - A: Volume 27, Issue 2, 1 April 2013, Pages 144-154

Abstract: Recently, to resolve problems regarding legal liability for accidents and disasters, various simulation techniques such as F.E.M. and F.V.M. have been used in the field of forensic engineering. In this study, we performed mechanical structure analysis using ADINA to investigate the cause of bridge collapse accidents. Such accidents occurred owing to modified and missing processes in comparison with the original design while filling with concrete. Modified and missing processes cause buckling of the upper plate and twisting of the main girder. Through this study, we determine the exact cause of bridge collapse by comparing the evaluation of the structure stability of the original design with the evaluation of the structure stability of the modified and missing process using ADINA structure analysis. Hence, this result indicates that buckling prediction through FEA is the most effective method.

Keywords: Buckling behavior - Finite element analysis - Forensic engineering - Instrumented indentation technique

 

Settlement analysis of a confined sand aquifer overlain by a clay layer due to single well pumping

Niu, W.-J.1, Wang, Z.2, Chen, F.2, Li, H.3

1 College of Mechanics and Engineering Department, Liaoning Technical University, Fuxin, Liaoning 123000, China

2 College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, Zhejiang 310058, China

3 Shanghai Geotechnical Investigations and Design Institute Co., Ltd., Shanghai 200031, China

Mathematical Problems in Engineering: Volume 2013, 2013, Article number 789853

Abstract: This paper proposes a simplified analytical solution to determine the primary consolidation settlement of a confined sand aquifer overlain by a clay layer due to single well dewatering. After single well pumping in a steady state, the Dupuit equation predicts the confined sand aquifer water head drawdown. The confining pressure on the underlain confined sand aquifer top surface is determined using the principle of vertical force equilibrium. Additional vertical stresses in each layer of the confined sand aquifer are then computed with the Boussinesq solution. The overall aquifer consolidation deformation is then determined with the e -lg p curve from the one-dimensional consolidation test and the applied vertical stress with the integral method. The proposed analytical solution is validated using the ADINA software, where porous media are simulated with the Biot model and solved with the 3D finite element method. This proposed analytical solution is used to simulate the primary consolidation settlement due to well pumping, using the fourth confined aquifer in the Pudong New Area of Shanghai from 1980 to 1995 as a case study. The predicted settlement compares reasonably well with the actual measured settlement in Shanghai.

 

Resolution of stokes equations with the Ca,b boundary condition using mixed finite element method

El-Mekkaoui, J.1, Elkhalfi, A.1, Elakkad, A.2

1 Departement of Genie Mecanique, Sidi Mohammed Ben Abdellah University, Faculte des Sciences et Techniques, B.P. 2202 -Route d'Imouzzer, Fès, Morocco

2 Centre Ŕegional des Ḿetiers d'Education et de Formation (CRMEF), Fès B.P: 243 Sefrou, Morocco

WSEAS Transactions on Mathematics: Volume 12, Issue 5, May 2013, Pages 586-597

Abstract: In this paper, we introduce the Stokes equations with a new boundary condition. In this context, we show the existence and uniqueness of the solution of the weak formulation associated with the proposed problem. To solve this problem, we use the discretization by mixed finite element method. In addition, two types of a posteriori error indicator are introduced and are shown to give global error estimates that are equivalent to the true error. In order to evaluate the performance of the method, the numerical results are compared with some previously published works and with others coming from commercial code like ADINA system.

Keywords: ADINA system - Ca,b Boundary condition - Mixed finite element method - Residual error estimator - Stokes equations

 

Biomechanics and computer simulation of the Z-plasty

Kitta, E., Akimoto, M.

Department of Plastic and Reconstructive Surgery, Nippon Medical School Chiba Hokusoh Hospital, Japan

Journal of Nippon Medical School: Volume 80, Issue 3, 2013, Pages 218-223

Abstract: Introduction: We compared the results of our computer simulation studies of Z-plasties of different design to those of earlier studies, such as laboratory studies in dogs. Material and Methods: The contours of single Z-plasties of different designs on flat surfaces were transferred to finite element analytical software (ADINA version 8.7). Results: The lengthening effect was almost proportional to the size of the Z-plasty, but was always less than what was predicted by geometric calculation. The percent gain in length decreased with the number of Z-plasties. Conclusion: We used ADINA software analyze the lengthening effects of Z-plasties of different patterns. Our results support those of earlier experiments and should help increase our understanding of Z-plasties of various patterns.

Keywords: Computer simulation - Finite element - Z-plasty

 

Free vibration of unidirectional sandwich panels, Part I: Compressible core

Frostig, Y.1, Phan, C.2, Kardomateas, G.2

1 Faculty of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, 32000, Israel

2 School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA, United States

Journal of Sandwich Structures and Materials: Volume 15, Issue 4, July 2013, Pages 377-411

Abstract: The free vibration response of a unidirectional sandwich panel with a compressible and incompressible core using the various computational models is presented and compared with closed-form elasticity solutions and finite element results. The mathematical formulations for various models along with the numerical investigation are presented in two parts. In the first part compressible core are considered using the elasticity closed-form solution and various high-order computational models such as the high-order sandwich panel theory (HSAPT) and the extended HSAPT model (EHSAPT). The second part is dedicated to incompressible cores and includes classical models, first-order and high-order shear deformable models, and zig-zag displacement pattern model, ordinary sandwich panel theory. The elasticity-based model serving as the benchmark solution (in first part) assumes isotropic, orthotropic, as well as layered core types. The mathematical formulation utilizes Hamilton's principle to derive the general equations of motion. A closed-form solution of the elasticity model is available only for a simply-supported panel and it is compared with all various models numerically. The numerical investigation includes: eigenfrequencies, displacement modes along the length and through the depth of panel, as well as stress modes through the depth of panel. The results of the various models are compared with the 2D elasticity solution and finite element results of ADINA. In general, the lower mode correlates well for all models while for the higher modes only the EHSAPT and the HSAPT with displacement formulation compared well.

Keywords: compressible core - computational models - eigenfrequencies - eigenmodes - free vibrations - high-order - Sandwich construction

 

A study on hemodynamic characteristics at the stenosed blood vessel using computational fluid dynamics simulations

Park, Y.-R.1, Kim, S.-J.2, Kim, S.-J.1, Kim, J.-S.2, Kang, H.-S.2, Kim, G.-B.2

1 Department of Chemical Engineering, Chonbuk National University, Jeonju, 561-756, South Korea

2 Department of Pharmacology, College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, South Korea

Journal of Biomedical Nanotechnology: Volume 9, Issue 7, July 2013, Pages 1137-1145

Abstract: In this study, we have used computational fluid dynamics to investigate the blood flow in the stenosed blood vessels. The numerical simulation using commercial software ADINA 8.6 were solved about the stenosed blood vessel according to the percent of stenosis and Reynolds number. The blood flow in the normal and stenosed blood vessel was grasped for the validity of the model. The characteristic of the pulsatile flow changed through the steady state flow and analysis of the pulsatile flow according to the time was grasped. The computational model with the characteristics of the fluid-structure interaction is introduced to investigate the wall shear stress, pressure distribution and axial flow velocity. The results show that axial flow velocity and wall shear stress in the region of stenosis was increased by increasing percent of stenosis and Reynolds number. Also, we can know that in the stenosed blood vessel the possibility of the generation of the aneurysm was increased by increasing Reynolds number and percent of stenosis.

Keywords: Abdominal aortic aneurysm - Atherosclerosis - CFD - Stenosed artery - Wall shear stress

 

Modelling of the temperature field within textile inlayers of clothing laminates

Korycki, R.1, Szafranska, H.2

1 Department of Techanical Mechanics and Computer Science, Lodz University of Technology, ul. Zeromskiego 116, 90-924 Łódź,K Poland

2 Department of Shoes and Clothing Technology, Radom Technical University, Radom, Poland

Fibres and Textiles in Eastern Europe: Volume 100, Issue 4, 2013, Pages 118-122

Abstract: Inlayers are introduced to improve the aesthetic qualities and stiffness against the creasing of clothing laminates. The laminate is created by the thermoplastic polymer glue between the inlayer and clothing material, softened by the heat. The connection is secured by the adhesive properties of the polymer and the pressure applied. The state variable is temperature. The heat transfer is described by the heat transport equation as well as by the set of boundary and intial conditions. The temperature distributions within the inlayers are determined by the numerical simulation for different temperatures of the heating plates. The temperature maps are shown by means of the graphical modulus of the program ADINA. The mean temperature of the polymer layer is next calculated.

Keywords: Clothing laminates - Heat transfer - Inlayer - Modelling

 

Impact analysis of mutual rotation of roller bearing rings on the process of contact stresses in rolling elements

Jakubovičová, L., Sága, M., Vaško, M.

Department of Applied Mechanics, Faculty of Mechanical Engineering, University of Žilina, Univerzitná 1, 010 26 Žilina, Slovakia

Manufacturing Technology: Volume 13, Issue 1, 2013, Pages 50-54

Abstract: The purpose of this paper is to present the magnitude of the impact of roller bearing rings mutual slewing to the process of contact stresses in rolling elements. The roller bearing satisfies prescribed basic static load rating if it is loaded by the maximum specified load only in the radial direction according to the ISO/TS 16281. However, the real roller bearings are not loaded only in the radial direction in practice. During operation there is mutual slewing of the bearing roller rings. This leads to a change in the conditions of contact and to a change in contact stresses. Stress state will be evaluated in the most loaded element of the roller bearing. Equivalent stress will evaluated according to the theory of HMH, stresses P1 to P3 at gradual slewing of the roller bearing rings, angle angle ø from 0' to 8'. For the analysis of this problem was used the finite-element program ADINA.

Keywords: ADINA - Computational analysis - Hertz contact stresses - Roller bearing - Stress analysis

 

Effect of tool shape on temperature field in friction stir spot welding

Lacki, P.1, Kucharczyk, Z.1, Śliwa, R.E.2, Gałaczyński, T.2

1 Czȩstochowa University Of Technology, 69 Da̧browskiego Str., 42-201 Czȩstochowa, Poland

2 Rzeszow University Of Technology, 8 Powstańców Warszawy Str., 35-959 Rzeszów, Poland

Archives of Metallurgy and Materials: Volume 58, Issue 2, 2013, Pages 595-599

Abstract:  Friction stir welding (FSW) is one of the youngest methods of metal welding. Metals and its alloys are joined in a solid state at temperature lower than melting points of the joined materials. The method is constantly developed and friction stir spot welding (FSSW) is one of its varieties. In the friction stir spot welding process a specially designed tool is brought into rotation and plunged, straight down, in the joined materials. Heat is generated as a result of friction between the tool and materials, and plastic deformation of the joined materials. Softening (plastic zone) of the joined materials occurs. Simultaneously the materials are stirred. After removal of the tool, cooling down the stirred materials create a solid state joint. Numerical simulation of the process was carried out with the ADINA System based on the finite element method (FEM). The problem was considered as an axisymmetric one. A thermal and plastic material model was assumed for Al 6061-T6. Frictional heat was generated on the contact surfaces between the tool and the joined elements. The model of Coulomb friction, in which the friction coefficient depends on the temperature, was used. An influence of the tool geometry on heat generation in the welded materials was analysed. The calculations were carried out for different radiuses of the tool stem and for different angles of the abutment. Temperature distributions in the welded materials as a function of the process duration assuming a constant value of rotational tool speed and the speed of tool plunge were determined. Additionally, the effect of the stem radius and its height on the maximum temperature was analysed. The influence of tool geometry parameters on the temperature field and the temperature gradient in the welded materials was shown. It is important regarding the final result of FSSW.

Keywords: Al 6061-T6 - FEM - Friction stir spot welding (FSSW) - Metal welding

 

The study of numerical analysis about the stability of tunnels with typical planes of fracture

Huang, B., Liu, R.J.

Southwest Jiaotong University, China

Applied Mechanics and Materials: Volume 353-354, 2013, Pages 1507-1510

Abstract: The optimum shape of the tunnel is usually decided by many factors. Not only should it ensure the stability of surrounding rock and the advantageous of masonry's stress, but also it need to meet the using requirements of the cavern, the convenience of the construction, the least excavated volume and the best economic results. Seeking the optimal shapes of the carven which is under the specific condition has always been paid great attention by engineers. With the help of ADINA finite element analysis software, this paper imitates related data in elastic theory about the excavation of tunnels with the typical planes of fracture which are under the same geology condition. After that, it contrasts the actual computing results with the theoretical analysis, and then studies planes of fracture's optimal excavated shapes of the tunnels.

Keywords: Theoretical analysis - numerical modeling - ADINA

 

FEA of flow fluid of six-wing synchronous varying clearance rotor

Guo, L.1,2, Wang, C.1,2, Bian, H.1,2

1 Shandong Provincial Key Laboratory of Polymer Material Advanced Manufacturings Technology, Qingdao University of Science and Technology, Qingdao, 266061, Shandong, China
2 College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, 266061, Shandong, China

Key Engineering Materials, Volume 561, 2013, Pages 59-63

Abstract: The six-wing synchronous varying clearance rotors which have been designed for the mixing of short fiber-rubber composite material have special structure, and considering the characteristic of the short fiber-rubber composite material, the flow situation of mixed rubber is very complex. However, the flow field of the six-wing synchronous varying clearance rotors can be analyzed by ADINA. So, the flow situation and mixing situation of the mixed rubber can be analyzed and judged by the FEA results such as the pressure field, viscosity field, shearing force field and velocity field.

Keywords: ADINA - FEA - Flow field - Synchronous rotor

 

The analysis and application on the typhoon-induced vibration control of the wind turbine with a pendulum damper

Li, J.1, Chen, J.Y.1, Chen, X.B.2

1 Dalian University of Tech, Dalian, 116023, China
2 Dongbei University of Finance and Economics, Dalian, 116025, China

Advanced Materials Research, Volume 773, 2013, Pages 193-198

Abstract: As a kind of high-rise structure, the offshore wind turbine is sensitive to wind load; it can generate strong dynamic responses to the excitation of typhoon. In this paper, a three-dimensional finite element model of offshore wind turbine is established with ADINA, responses under strong wind excitation are numerically simulated and performed subsequently. The fluctuating wind velocity time series are simulated by the method of HSM (harmony superposition method). Based on the modal and tine-history analyses of the structures together with self-vibration character, the pendulum damper is employed to control the resulting undesirable vibrations that are induced by wind. With the damper installed, the displacement and acceleration of the tower are reduced by as much as 40% using 1% of the total effective mass.

Keywords: Pendulum damper - Vibration control - Wind excitation - Wind turbine

 

Simulation of sheet-titanium forming of welded blanks

Lacki, P.

Czestochowa University of Technology, ul. J.H. Dabrowskiego 69, 42-201 Czestochowa, Poland

Computational Plasticity XII: Fundamentals and Applications - Proceedings of the 12th International Conference on Computational Plasticity - Fundamentals and Applications, COMPLAS 2013, Pages 854-861

Abstract: The increase in demand for the light and tough drawn-parts causes the growing interest in sheet metal forming of Tailor-Welded Blanks (TWB). Application of such blanks allows for achieving in one operation the drawn-parts characterized by diverse strength and functional properties. It also allows for reduction of material waste and decrease in number of parts needed to produce component. Weight reduction is especially important for the car and aircraft industry. Forming welded blanks requires solving many problems such as different plasticity of the joined materials, presence of the weld and its dislocation. In order to evaluate suitability of welded blanks for the forming processes, it is necessary to carry out several studies, including numerical simulations of the process, that will allow for prediction of sheet behaviour in consecutive forming stages. Although to date aluminium and steel TWBs are mainly used, the aircraft industry is also interested in application of titanium TWBs. Generally sheet-titanium forming is more difficult than steel or aluminium sheets. The weld presence complicates the forming process additionally. In the paper some numerical simulation results of sheet-titanium forming of welded blanks will be presented. Forming the spherical caps from the uniform and welded blanks will be analysed. Grade 2 and Grade 5 (Ti6Al4V) titanium sheets with thickness of 0.8 mm will be examined. A three-dimensional model of the forming process and numerical simulation will be performed using the ADINA System v.8.6, based on the finite element method (FEM). An analysis of the mechanical properties and geometrical parameters of the weld and heat affected zone (HAZ) are based on the experimental studies. Drawability and possibilities of plastic deformation will be assessed basing on the comparative analysis of the determined plastic strain distributions in the drawn-parts material and thickness changes of the drawn-part wall. The results obtained in the numerical simulations will provide important information about the process course. They will be useful in design and optimization of the forming process.

Keywords: FEM modelling - Sheet-metal forming - Ttitanium sheet - TWB blanks

 

Numerical and experimental analysis of cold forming of titanium alloy sheets

Adamus, J.

Czestochowa University of Technology, ul. J.H. Dabrowskiego 69, 42-201 Czestochowa, Poland

Computational Plasticity XII: Fundamentals and Applications - Proceedings of the 12th International Conference on Computational Plasticity - Fundamentals and Applications, COMPLAS 2013, Pages 247-255

Abstract: Due to an increasing demand for the titanium drawn-parts, mainly from the aerospace and car industries, the demand for expertise in sheet-titanium forming grows. Although titanium combine many valuable features like lightweight with high strength and excellent corrosion resistance, its application is still limited because titanium processing, especially cold forming of titanium sheets poses many problems. In the paper technological problems with forming of titanium sheets is discussed. A special attention is paid to flexible forming. The experimental and numerical simulation results of semi-flexible forming are presented. The numerical analyses are carried out with the ADINA System v. 8.6 basing on the Finite Element Method (FEM). A spherical drawn-part made of Ti6Al4V titanium sheet is analysed. The material data, which are necessary for the numerical calculations, such as tensile strength Rm, yield point Re, R-value and hardening coefficient n were determined experimentally. The numerical calculations show good convergence with the experiments.

Keywords: Numerical Simulation - Semi-flexible Forming Process - Titanium Alloy

 

Fluid-solid coupling based seismic response analysis of subsea tunnels during seepage

Cheng, X1,2, Wang, J.1, Du, X.2

1 School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, China
2 Key Laboratory of Urban Security and Disaster Engineering of Education, Beijing University of Technology, Beijing 100124, China

Modern Tunnelling Technology,Volume 50, Issue 6, 2013, Pages 44-51

Abstract: To study the effects of seepage and earthquakes on a subsea tunnel structure, a subsea tunnel passing through a fracture zone was selected to be studied. The surrounding rock was defined as a continuous porous medium. Considering the visco-elastic artificial boundary and fluid-solid action between the surrounding rock and pore water, the finite element software ADINA was used to analyze the variation of pore water pressure in the tunnel surrounding rock during horizontal seismic action, the effects of hydrodynamic pressure in a porous medium on the tunnel lining and the effects of the combined action of a porous medium seepage field and seismic stress field on tunnel safety and stability. The numerical calculations show that the effects of hydrodynamic pressure in a porous rock medium on the structural internal force of a tunnel during seepage is significant and must be addressed. Additionally, the stresses and strains at the spandrel, the springing, and both sides of the tunnel lining increase dramatically under seismic action.

Keywords: Fluid-solid coupling - Seepage - Seismic response - Subsea tunnel - Visco-elastic artificial boundary

 

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