Search results

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming, powder metallurgy and composite material processing are briefly discussed. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for 1994‐1996, where 1,370 references are listed. This bibliography is an updating of the paper written by Brannberg and Mackerle which has been published in Engineering Computations, Vol. 11 No. 5, 1994, pp. 413‐55.

This paper gives a review of the finite element techniques (FE) applied in the area of material processing. The latest trends in metal forming, non‐metal forming and powder metallurgy are briefly discussed. The range of applications of finite elements on the subjects is extremely wide and cannot be presented in a single paper; therefore the aim of the paper is to give FE users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An appendix included at the end of the paper presents a bibliography on finite element applications in material processing for the last five years, and more than 1100 references are listed.

To provide a selective bibliography for researchers working with bulk material forming (specifically the forging, rolling, extrusion and drawing processes) with sources which can help them to be up‐to‐date.

A range of published (1996‐2005) works, which aims to provide theoretical as well as practical information on the material processing namely bulk material forming. Bulk deformation processes used in practice change the shape of the workpiece by plastic deformations under forces applied by tools and dies.

Provides information about each source, indicating what can be found there. Listed references contain journal papers, conference proceedings and theses/dissertations on the subject.

It is an exhaustive list of papers (1,693 references are listed) but some papers may be omitted. The emphasis is to present papers written in English language. Sheet material forming processes are not included.

A very useful source of information for theoretical and practical researchers in computational material forming as well as in academia or for those who have recently obtained a position in this field.

There are not many bibliographies published in this field of engineering. This paper offers help to experts and individuals interested in computational analyses and simulations of material forming processes.

Numerical simulation of the single point incremental forming (SPIF) processes can be very demanding and time consuming due to the constantly changing contact conditions between the tool and the sheet surface, as well as the nonlinear material behaviour combined with non-monotonic strain paths. The purpose of this paper is to propose an adaptive remeshing technique implemented in the in-house implicit finite element code LAGAMINE, to reduce the simulation time. This remeshing technique automatically refines only a portion of the sheet mesh in vicinity of the tool, therefore following the tool motion. As a result, refined meshes are avoided and consequently the total CPU time can be drastically reduced.

SPIF is a dieless manufacturing process in which a sheet is deformed by using a tool with a spherical tip. This dieless feature makes the process appropriate for rapid-prototyping and allows for an innovative possibility to reduce overall costs for small batches, since the process can be performed in a rapid and economic way without expensive tooling. As a consequence, research interest related to SPIF process has been growing over the last years.

In this work, the proposed automatic refinement technique is applied within a reduced enhanced solid-shell framework to further improve numerical efficiency. In this sense, the use of a hexahedral finite element allows the possibility to use general 3D constitutive laws. Additionally, a direct consideration of thickness variations, double-sided contact conditions and evaluation of all components of the stress field are available with solid-shell and not with shell elements. Additionally, validations by means of benchmarks are carried out, with comparisons against experimental results.

It is worth noting that no previous work has been carried out using remeshing strategies combined with hexahedral elements in order to improve the computational efficiency resorting to an implicit scheme, which makes this work innovative. Finally, it has been shown that it is possible to perform accurate and efficient finite element simulations of SPIF process, resorting to implicit analysis and continuum elements. This is definitively a step-forward on the state-of-art in this field.

Gives a bibliographical review of the error estimates and adaptive finite element methods from the theoretical as well as the application point of view. The bibliography at the end contains 2,177 references to papers, conference proceedings and theses/dissertations dealing with the subjects that were published in 1990‐2000.

Asphalt mixture is widely used in road engineering, and its performance research is particularly important. But the study of asphalt mixture performance needs a lot of tests, such as bending test, splitting test and so on. It also needs a lot of time and material resources. The purpose of this paper is to obtain test results through finite element numerical simulation, and show that this saves a lot of manpower and material resources.

The mechanical parameters of the material are obtained through uniaxial compression tests. The true stress and plastic strain are calculated according to nominal stress and nominal strain. A constitutive model is established. Then a finite element model of asphalt mixture is established. The numerical simulation and performance study of asphalt mixture bending test is carried out. At the same time, according to the above method, the asphalt mixture is subjected to freeze-thaw cycles and ultraviolet aging, and the mechanical parameters are obtained by a uniaxial compression test. A numerical model is established to simulate the bending characteristics of asphalt mixture after freeze-thaw cycles and ultraviolet aging.

A uniaxial compression test of the asphalt mixture is conducted to obtain nominal stress and nominal strain. The true stress and plastic strain are calculated and the elastic modulus is established with Poisson’s ratio as the elastic part, and the true stress and plastic strain as the plastic part. The model is constructed, the finite element model is established and the bending test is numerically simulated. The verified trend is consistent, and the method is feasible. According to the above method, the concrete is subjected to freeze-thaw cycle and ultraviolet aging, and the finite element model is established by using uniaxial compression test to obtain parameters. The bending test is simulated and the verification method is feasible. With the increase of the number of freeze-thaw cycles and the increase of UV aging time, the maximum bending strain of SBS modified asphalt mixture and matrix asphalt mixture is decreased .The low-temperature performance of SBS modified asphalt mixture is better than that of matrix asphalt mixture.

A method of simulating asphalt mixture test by finite element method numerical simulation is established. By using this method, the performance of asphalt mixture is studied, which saves a lot of manpower and material resources. At the same time, this method can be used to study the characteristics of asphalt mixture under complex conditions.

Gives a bibliographical review of the finite element meshing and remeshing from the theoretical as well as practical points of view. Topics such as adaptive techniques for meshing and remeshing, parallel processing in the finite element modelling, etc. are also included. The bibliography at the end of this paper contains 1,727 references to papers, conference proceedings and theses/dissertations dealing with presented subjects that were published between 1990 and 2001.

The discrete element methods (DEM) are numerical techniques that have been specifically developed to enable simulations of systems of multiple distinct, typically infinitely rigid, bodies that interact with each other through contact forces. However, there are multibody systems for which it is useful to consider the deformability of the simulated bodies and enable the evaluation of their stress and strain distributions. This paper focuses on the simulation of deformable multibody systems using a combination of DEM and finite element methods (FEM). In particular, an updated Lagrangian (UL) finite element (FE) formulation and an explicit time integration scheme are used together with some simplifying assumptions to linearize this highly nonlinear contact problem and obtain solutions with realistic computational cost and sufficiently good accuracy. In addition, this paper describes a software implementation of this formulation, which utilizes the Java programming language and the Java3D graphics application programming interface (API), as well as database technology.

It has been observed from the history of failed dies used in local extrusion industry that after certain press cycles, severe die damage occurs by using more number of in‐house recycled billets. The purpose of this paper is to focus on the effect of billet quality on the extrusion die service life, based on using microstructural and finite element analyses.

Numerical solution of stress distribution in extrusion die using microstructural and finite element analyses.

Simulation results demonstrate that extrusion die experiences high stresses and strains at critical locations by running secondary billets. Billet deformation behavior also shows that secondary billet has more resistance to flow during extrusion cycle, which results in such high stresses and strains in the die.

The study includes a particular die used to extrude the aluminum alloy billets. It may need to generalized including materials other than aluminum alloy.

The findings are original and believed to be useful for engineers working in the extrusion dies. Since it is shown that secondary billets (recycled billets) have more resistance to flow in the dye, a care should be taken when estimating the die life for the practical applications.

It is an original work. It deals with the comparison of new and recycled billets's performance in terms of stress formation in the die during the extrusion cycle.

This paper aims to introduce the principle of the mask exposure and scanning stereolithography (MESS) and to develop a simulation code to analyze the MESS process.

Photopolymerization is a key reaction in stereolithography. It brings about molecular linkage and releases exothermic temperature. The shrinkage effect is the major cause of prototype deformation, and the shrinkage resulting from scanning and mask exposing is different. It is important to analyze the inaccuracy of each curing layer after the mask exposing in order to optimize the scanning parameters. A simulation code, based on dynamic finite element method, to analyze the shrinkage effect in accordance with scanning path and mask exposure pattern. A benchmark model has been proposed to validate the implementation of the developed code.

The simulation results show that the developed code can analyze the deformation in laser scanning, masking exposing and the MESS process. In benchmark model study, the sharp corner shrinks faster than rounded edge in mask pattern curing. Although the profile scanning can maintain the high accuracy in the MESS process, the residual stress is easily discovered inside of the sharp corner.

The developed simulation code can be applied for optimizing scan path and exposing time due to the analysis process in accordance with the drawing path and fabrication parameters.