H and P Mesh Refinement in the Metal-Forming F.E.M. Analysis

In this paper a comparison between H and P refinement techniques in the metal-forming F.E.M. analysis is carried out in order to evaluate their computational efficiency. The results are compared using a particular error estimator which locally allows determining the workpiece zones where the refinement is necessary.

A New Numerical Method for Axisymmetrical Forming Processes

Summary In this paper a numerical method for the analysis of axisymmetrical forming processes is proposed. This method represents the last development of a previous one which allows to solve forming problems in plane strain condition. The proposed model is baaed on the finite element discretization and on the linearization of the yield surface which leads to solve a LP problem. Two different examples of application, concerning the upsetting of a cylinder and of a hollow disk are reported.

Investigation of electrode material - redox couple systems for reverse electrodialysis processes

Error Estimates and Automatic Adaptive Mesh Refinement for the Metal Forming FEM Analysis

The Authors propose a new technique which enables a estimation of the error inherent with the FEM analysis of metal forming processes. The aim is to evaluate the zones where the error is higher in order to proceed to a refinement of the mesh in such zones, and to obtain a smaller value of the global error. Moreover, to simplify the analyst work in the progressive refinement of the mesh, it has been prepared a software able to read the drawing created by a CAD program and to generate, automatically, all the geometrical and topological data necessary to perform the analysis on Personal Computer. The automatic renumbering of the elements in the refined mesh has been performed with the aim to r…

A Numerical Method for the Analysis of Plane-Strain Forming Processes with Unilateral Constraints

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.

Limits of the Open-Die Forward Extrusion: Numerical Analysis and Experimental Tests

In the paper the open-die forward extrusion process is analysed in order to determine the influence of the most important geometrical and frictional parameters on the practical suitability of the operation. Experimental tests have been carried out and their results have been compared with the numerical ones derived by FEA.

The Continuous Extrusion Process CONFORM: a full 3D Thermal and Mechanical Analysis

The principle of the Conform extrusion process is based on the action of a rotating wheel that drags and push the feed material by means of the frictional force existing between them. The Conform process has several advantages over the traditional extrusion processes. The preheating phase may be neglected, so that furnaces for heating are not necessary; furthermore, the product is continuous and welding phase of the billets is not required. The influence of three operative parameters, die geometry, velocity and die cooling rate, has been analysed in this paper by means of an “outranking approach” able to give precious indications for the assessment of the process.