ADINA System Research Articles

Analysis of Tensile Test of Titanium EBW Sheet

The continuous pursuit of vehicle weight reduction forces the industry to look for alternative materials to steel. Light alloys such as aluminium or titanium are materials that provide a decrease in weight using conventional technologies. Additional weight reduction results from using tailor-welded blanks (TWB). While the joining and forming steel or even aluminium TWBs is quite well known and described in the technical literature, joining and forming titanium TWBs still poses a significant problem. In the paper, experimental tests carried out with welded samples manufactured from commercially pure titanium Gr 2 and titanium alloy Gr 5 sheets are presented. The samples were joined by electron beam welding. Mechanical testing and optical microscopy were used to characterise the welds and the base metal of the samples. The samples were subjected to uniaxial tension up to final failure. The 3‑D Digital Image Correlation system ARAMIS was used for monitoring the whole deformation process. This makes it possible for real-time observation of sample deformation. The test results and the numerical analysis of the tensile tests are compared. The numerical simulations were carried out with the ADINA System based on the Finite Element Method (FEM). The mechanical analysis leads to calculation of the strain state after sample deformation in uniaxial tension (mechanical model).

NUMERICAL ANALYSIS OF THE SCREW CONNECTION WITH PRELOAD TENSION USED IN THE MOUNTING OF SLEWING BEARINGS

Slewing bearings are used as devices that connect two part working machine, usually with a rotating chassis body must meet safety criteria, manage to cope with extreme loads and environmental factors operation life. In this paper the distribution of pressure on surfaces of the screw’s connections with preload tension is considered. A joining model which is used in rolling bearing is the subject of the analysis. The aim of the work is to introduce an auxiliary criterion of ‘connection tightness’ to the calculating methodology of bearings’ fastening connections with building structure. Considered part of the three-row roller bearing, rings bearings and mounting elements are modelled solid type, and the bolts are modelled with beam-type element introduced preload tension value equivalent catalogue. Connected elements of the screw head rigid elements. The screws used in such a combined coronary bearings are not close fit, and established contact between the surfaces of the rings and the building is not homogeneous. Work is not only dedicated to the stress of contact between the contact surfaces A and B, but also considered is the effect of pitch spacing of the screws on the pitch rolling element bearing in the numerical solution ADINA system was used to prepare numerical models of junction. The results of the calculations of pressure distributions for changeable screw’s span are shown graphically and the table of percentages of the load loss of contact between the surfaces A and B of slewing bearing screw connection.

Numerical Analysis of Aluminium Cellular Beams with Cells of Different Diameters

The paper presents a numerical analysis of aluminium cellular beams. The ADINA System based on the Finite Element Method (FEM) is used for the calculations. The beams made of 6061-T6 aluminium alloy are analysed. Such beams are used in civil engineering and aircrafts industry as the load-bearing parts. The beam components are joined by Refill Friction Stir Spot Welding (RFSSW). The I-profile beams with cells of different diameters, i.e. 62, 72 and 82 mm, in the webs are analysed. In each case, cell arrangement in the beam is the same. The bending of the fixed-end beams with concentrated load is analysed. Extreme values of the displacement for the beams material and RFSSW joints are emphasized. The effective stresses for the beams and FSSW joints are calculated. Normal stresses in the top flanges, bottom flanges and webs are given.

Numerical Analysis of Aluminum Cellular Beams with Cells of Different Arrangement

The paper presents a numerical analysis of cellular beams with cells of different arrangement. The ADINA System based on the Finite Element Method (FEM) is used in the calculations. The beams made of 6061-T6 aluminum alloy are analysed. Such beams are used in civil engineering and aircraft industry as load-bearing parts. The beam components are joined by Refill Friction Stir Spot Welding (RFSSW). The I-profile beams with cell diameter of 62 mm are analysed. The beam length is 0.8 m and its cross section is 50x100mm. The bending of fixed-end beams with concentrated load is analysed. Extreme values of the displacement for the beams material and RFSSW joints are emphasized. The effective stresses for the beams and RFSSW joints are calculated. Normal stresses in the top flanges, bottom flanges and webs are given.

The influence of overload stresses on durability of ceramic elements in hip joint endoprostheses

Journal of Applied Mathematics and Computational Mechanics, Prace Naukowe Instytutu Matematyki i Informatyki, Politechnika Częstochowska, Scientific Research of the Institute of Mathematics and Computer Science, Czestochowa University of Technology

Natural frequency analysis of fluid-conveying pipes in the ADINA system

In this paper we present analysis and numerical simulations for the natural frequency of pipes conveying fluid in the ADINA system. The slender pipe structures are modelled as shells and the fluid flows are supposed to be three-dimensional (3D) and incompressible. The fluid and structural models are mechanically coupled on their interface through slip and displacement conditions. Several numerical examples for pipes shaped as different configurations show that the natural frequencies obtained based on ADINA codes are generally lower than those predicted by analytical or dynamic stiffness methods. In particular, for curved pipes conveying fluid with relatively high flow velocity, it is found that the evolution trend of natural frequencies with increasing flow velocity is similar as that predicted by the inextensible theory for curved pipes conveying fluid.

Numerical analysis of stress and strain occuring in the contact area of ceramic head - ceramic cup in the hip endoprostheses

The paper presents the results of numerical analysis of the system “ceramic head ceramic cup” in the hip joint endoprosthesis. Applying the Al2O3 ceramics in this kind of solutions, apart from all values of this material, can lead to grinding, if a high load is used. The analysis was run on the ADINA system. The geometrical model was elaborated on real measurements of the elements of endoprosthesis and also on the results provided by the producer.

Effect of Tool Shape on Temperature Field in Friction Stir Spot Welding

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.

Resolution of Unsteady Navier-stokes Equations with the C a,b Boundary condition

in this work, we introduce the unsteady incompressible Navier-Stokes equations with a new boundary condition, generalizes the Dirichlet and the Neumann conditions. Then we derive an adequate variational formulation of time-dependent Navier- Stokes equations. We then prove the existence theorem and a uniqueness result. A Mixed finite-element discretization is used to generate the nonlinear system corresponding to the Navier-Stokes equations. The solution of the linearized system is carried out using the GMRES method. In order to evaluate the performance of the method, the numerical results are compared with others coming from commercial code like Adina system.

A Posteriori Error Estimator for Mixed Approximation of the Navier-Stokes Equations with the Boundary Condition

In this paper, we introduce the Navier-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 latter, 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.

Investigation of Sheet-Titanium Forming with Flexible Tool – Experiment and Simulation / Badanie Kształtowania Blach Tytanowych Z Wykorzystaniem Elastycznego Narzędzia - Doświadczenie I Symulacja

In the paper the results of investigation of sheet-titanium forming with flexible tool are presented. Titanium alloy sheets belong to a group of materials which are very hard to deform at ambient temperature. To improve sheet formability forming technology using a semi-flexible tool was implemented. Experiments were carried out on a specially designed for this purpose device. Due to the application of a rubber pad the stress state similar to triaxial compression was produced in the deformed material. Such a stress state made it possible to obtain higher material deformation without risk of fracture. The numerical simulations were used for analysing the flexible forming process. The ADINA System basing on the Finite Element Method (FEM) was applied.

AN A POSTERIORI ERROR ESTIMATE FOR MIXED FINITE ELEMENT APPROXIMATIONS OF THE NAVIER-STOKES EQUATIONS

In this work, a numerical solution of the incompressible Navi- er-Stokes equations is proposed. The method suggested is based on an algorithm of discretization by mixednite elements with a posteriori er- ror estimation of the computed solutions. In order to evaluate the per- formance of the method, the numerical results are compared with some previously published works or with others coming from commercial code like Adina system.

Numerical simulation of the electron beam welding process

Electron beam welding is a highly efficient and precise welding method that is being increasingly used in industrial manufacturing and is of growing importance in industry. Compared to other welding processes it offers the advantage of very low heat input to the weld, resulting in low distortion in components. Modeling and simulation of the laser beam welding process has proven to be highly efficient for research, design development and production engineering. In comparison with experimental studies, a modeling study can give detailed information concerning the characteristics of weld pool and their relationship with the welding process parameters (welding speed, electron beam power, workpiece thickness, etc.) and can be used to reduce the costs of experiments. A simulation of the electron beam welding process enables estimation of weld pool geometry, transient temperature, stresses, residual stresses and distortion. However this simulation is not an easy task since it involves the interaction of thermal, mechanical and metallurgical phenomena. Understanding the heat process of welding is important for the analysis of welding structure, mechanics, microstructure and controlling weld quality. In this paper the results of numerical simulation of electron beam welding of tubes were presented. The tubes were made of 30HGSA steel. The numerical calculation takes into consideration thermomechanical coupling (TMC). The simulation aims at: analysis of the thermal field, which is generated in welding process, determination of the heat-affected zone and residual stresses in the joint. The obtained results allow for determination both the material properties, and stress and strain state in the joint. Furthermore, numerical simulation allows for optimization of the process parameters (welding speed, power of the heat source) and shape of the joint before welding. The numerical simulation of electron beam welding process was carried out with the ADINA System v. 8.6. using finite element method.

A Finite Element Approximation of the Stokes Equations

In this work, a numerical solution of the incompressible Stokes equations is proposed. The method suggested is based on an algorithm of discretization by the unstable of Q1 – P0 velocity/pressure ?nite element approximation. It is shown that the inf-sup stability constant is O(h) in two dimensions and O( h2) in three dimensions. The basic tool in the analysis is the method of modi?ed equations which is applied to ?nite difference representations of the underlying ?nite element equations. In order to evaluate the performance of the method, the numerical results are compared with some previously published works or with others coming from commercial code like Adina system.

Forming of the titanium elements by bending

Titanium alloys are superior to nearly all metals in terms of a combination of high mechanical strength and low weight. Therefore, titanium is used whenever the construction weight and its strength are essential. Bending is one of the most frequently used methods for forming titanium elements. However, current knowledge of titanium and its alloys forming by cold working is insufficient. Many phenomena, such as spring-back, need to be investigated and explained.This study was undertaken in order to investigate the titanium bending process. A numerical simulation of the bending of a Ti6Al4V ELI titanium alloy bar was carried out with the Adina System, based on the finite element method. The influence of bar diameter, bending radius and bending angle on the strain and stress distribution in the deformed element was analysed. The numerical calculations demonstrated that the spring-back was dependent on the size of the middle material zone, which remained in an elastic state during bending process. This in turn was dependent on the value of the bending radius, bending angle and diameter/thickness of the bent element. Knowledge of the spring-back is very important because it essentially decreases the forming accuracy of the bent elements. This is especially important when vital titanium elements, such as: body implants or aircraft elements, are bent. Therefore, the calculation results were validated experimentally.

Stamping of Titanium Sheets

In this paper, some technological problems (e.g. low drawability, high susceptibility to galling, spring-back) occurring in the sheet-titanium forming process are discussed. A numerical simulation of the stamping process was carried out with the Adina System v.8.3 based on the finite element method. The effects of friction, the holding-down force and tool geometry on the course of the stamping process were analysed. The mechanical and technological material data needed for the calculations were determined experimentally. The friction coefficients for the frictional pair: ”titanium – tool steel” for different lubricants and antiadhesive layers determined in the “strip drawing” test were found. The role played by lubrication and antiadhesive layers in preventing titanium “build-ups” on the tools is presented. The calculated results were then confirmed experimentally.

The Influence of Cutting Methods on the Cut-Surface Quality of Titanium Sheets

In this paper, the influence of the cutting method on the cut-surface quality is analysed. A WT1-0 titanium sheet was cut in three different ways: using a guillotine, a laser and an abrasivewaterjet. The cut-surface’s appearance, microstructure, microhardness and the roughness of the cutsurface were tested. Moreover, a numerical simulation of the banking process of a titanium disk was carried out with the ADINA System v.8.3 based on the finite element method. The influence of the radius of the cutting edge and the clearance on the surface quality was analysed.

Optimisation of the Stamping Parameters of a Drawn-Part Made of Stainless Steel

Demand for an increase in the useable properties of a drawn-part made of stainless steel has been the inspiration for the work. The use of 4H13 steel instead of 3H13 has resulted in the higher strength of the drawn-part but also a decrease in drawability. Therefore, some modifications to the original design of the sheet-metal forming process were necessary. A numerical simulation was applied to optimise of the stamping process. The ADINA System based on the finite element method (MES) was used. Frictional conditions on the contact surfaces, blank diameter and the course of the blank holding force versus time were analysed. In this paper, the test results of the mechanical properties of the analysed sheets (3H13 and 4H13 stainless steel) are given, some differences in the way of stamping drawn-parts made of these materials are discussed and the results of the numerical simulation are presented. A 3D model and perfectly rigid tool were assumed in the numerical model. The sheet was modelled using shell elements. The elastic and plastic properties of the sheet material were assumed and the frictional conditions on the contact surfaces were taken into consideration during the numerical simulation. Based on the numerical simulation the stamping process was optimised. A comparison between the numerical calculation and test results shows good convergence. Thanks to the MES analysis and the application of the new technological parameters, the desired drawn-part with the better useable properties was obtained.

Deformability of WC–Co sinters and 17-4 PH steel brazed joints

Tests of the vacuum brazing joints of WC–Co sinters and age-hardened steels of the 17-4 PH using the Cu solder were carried out. Stresses and strains of the joints have been analysed. The joints have been used in large dimension spinning nozzles of a die for polyethylene granulation, in that considerable strength and ductility of the joints are required. Shearing tests of the joints have been executed on specimens done in the spinning nozzle brazed joint model. The results of mechanical properties of the joint tests were a base for the fooling them numerical investigations. 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 an essential influence on the values of the local stress and the significant influence on the joint rigidity. In a case of the considered joints the values of the local stress differences have been considerable (a few hundred percent) in dependence of a fixed load manner.

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

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.