Search results for "Forming processes"
showing 10 items of 73 documents
Incremental forming of friction stir welded taylored sheets
2006
In the last decade sheet metal forming market has undergone substantial mutations since the development of more efficient strategies in terms of flexibility and cost reduction is strictly due. Such requirements are not consistent with traditional metal stamping processes which are characterized by complex equipment, capital and tooling costs; thus the industrial application of such processes is economically convenient just for large scale productions. For this reason most of the research work developed in the last years has been focused on the development of new sheet forming processes able to achieve the above discussed goals. Contemporary, with particular reference to the automotive indus…
A numerical approach for the modelling of forming limits in hot incremental forming of AZ31 magnesium alloy
2021
AbstractMagnesium alloys, because of their good specific material strength, can be considered attractive by different industry fields, as the aerospace and the automotive one. However, their use is limited by the poor formability at room temperature. In this research, a numerical approach is proposed in order to determine an analytical expression of material formability in hot incremental forming processes. The numerical model was developed using the commercial software ABAQUS/Explicit. The Johnson-Cook material model was used, and the model was validated through experimental measurements carried out using the ARAMIS system. Different geometries were considered with temperature varying in a…
Comparative Study for Springback Prediction on Single Point Incremental Forming Process
2014
The present paper proposes a comparative study in order to determine the springback in single point incremental forming process. Using the Ls-Dyna software the process was simulated for one piece in frustum of pyramid shape. In the end of the explicit dynamic analysis, it was run, using the same software, an implicit analysis to determine the springback. For this comparison study we selected four different shell formulations. The results obtained in this simulation were compared with those obtained experimentally for the same part. The experimental research was conducted on a robot and, on the opposite side of the machined surface, an Aramis measuring optical system was placed to allow the …
Comparison between aluminum alloys behavior in incremental sheet metal forming process of frustum pyramid shaped parts
2021
Abstract Single point incremental forming is a new emerging technology, used mainly for prototype development or small series production, with good prospects in industrial implementation. However, the parts manufactured through this process often presents low accuracy, thus the industrial implementation is yet limited. Incremental forming process can be done with the help of different technological equipment, such as industrial robots and numerically controlled machines. Since the process is still in development phase, it is a good practice to use finite element analysis software packages in order to reduce time and costs to produce accurate parts. The aim of this paper is to investigate th…
Comparison of analytical methods and AI tools for material characterisation in hot forming
2002
Abstract Hot forming processes probably represent the most ancient of forming operations and what is more they are still today commonly used in modern mechanical industry in order to obtain sound parts, achieving large deformations with a limited required power. Hot metal forming operations are characterised by a large number of physical and thermal phenomena which have to be taken into account in order to model and design the processes themselves. Actually several thermally activated phenomena occur during the forming processes such as recovery, recrystallisation, grain growth, precipitation, allotropic transformations, etc. In this paper the comparison between an analytical method based o…
A Numerical Method for the Analysis of Plane-Strain Forming Processes with Unilateral Constraints
1983
The Authors propose a numerical model for the solution of plane-strain forming processes, based on the linearization of the yield surface. This allows to employ the linear programming technique for the solution of the variational problem derived from the application of the upper-bound theorem. Such a model permits to take into account the unilateral constraints in a very simple way. Therefore it is well suited to solve a large class of problems, such as sheet forming, in which the unilateral constraints are often present.
Advanced numerical models for the thermo-mechanical-metallurgical analysis in hot forging processes
2013
In the paper a literature review of the numerical modeling of thermo-mechanical-metallurgical evolutions of a metal in hot forging operations is presented. In particular models of multiaxial loading tests are considered for carbon steels. The collected examples from literature regard phases transformations, also martensitic transformations, morphologies evolutions and transformation plasticity phenomena. The purpose of the tests is to show the correlation between the mechanical and the metallurgical behavior of a carbon steel during a combination of several types of loads. In particular a few mechanical tests with heat treatment are analyzed. Furthermore, Ti-6Al-4V titanium alloy is conside…
Numerical simulation of material failure in single point incremental forming process
2019
Abstract The sheet metal parts obtained through single point incremental forming process show a thinning and also there is a high possibility of material failure. In order to avoid the failure of the material during the process, it is a good practice to use numerical simulation through finite element method to prevent this phenomenon. The aim of this paper is to investigate the prediction of the failure moment of the aluminium sheet metal using various failure criteria. Commonly used failure criteria are: Tresca or maximum shear stress criterion, von Mises yield criterion, Hill yield criteria and various invariants of the Cauchy stress tensor. For the numerical simulation of the single poin…
Forming of aluminum foam sandwich panels: Numerical simulations and experimental tests
2006
Abstract The forming of the completed aluminium foam sandwich (AFS) panels would determine an improvement in the manufacturing of parts and panels. In this paper the authors have investigated the formability of AFS through experiments and numerical simulations. As far as the former are concerned, commercially prepared panels have been considered and bending and stamping processes have been taken into account. In addition, FEM analyses have been developed, utilizing a porous material model following the evolution of the material density throughout the forming processes.
MICRO-SCALE STUDY OF RESIDUAL STRESSES IN CR2O3 COATINGS SPRAYED BY APS
2020
International audience; Whichever the application field, every material forming process generates residual stresses on the surface. While they are likely to enhance the aimed properties of the final mechanical part, these stresses may also drastically reduce them and result in early failures. Therefore, understanding the residual stress state remains a major challenge when coating complex parts, especially as most characterization methods at the microscopic scale involve specific sample preparation procedures which may affect the residual stresses field. This work investigates the residual stress state that exists in chromium oxide coatings deposited via Atmospheric Plasma Spray (APS), usin…