TPT May 2011

A rticle FEM analysis of a pipe forming process Sven Renkel – SMS Meer GmbH, Germany

Introduction The comprehensive parametric 3D design of welded tube plants using the Pro/Engineer Wildfire 3.0 (M230) CAD system from PTC offers SMS Meer not only collision analyses and an almost perfect design system, but also an outstanding interface to other systems, such as Finite Elements Method systems. The linking of FEM systems to the design data is therefore the next logical step under these preconditions. In addition to independent FEM simulations, SMS Meer now integrates its simulation technology deep into die CAD environment of its design work. The use of FEM computations therefore becomes expedient even during the development of new plants and when designing new concepts. It has thereby been discovered that particularly for the compilation of the simulation data, it is of benefit to follow this route since all the necessary data are already available in 3D format at SMS Meer.

Overview and structure of spheroidization of a 26" tube forming by SMS Meer

Pro/ENGINEER links geometric data and positions right up to special settings across various departments within the company. All the data are available in real time via the PDMLink 9.1 (M020) system and are already merged there. It is therefore expedient to use these structures and to also make them available for the simulation. An extensive benchmarking took place at SMS Meer in 2009. The simufact.forming system was found to be best in all areas at that time, and it was soon discovered that the system also has a high integration capability. Present practice Pipe forming processes are already computed using the finite elements method today. Of course there are discrepancies between the computer model and the situation in practice. The computations are performed using an optimised MSC.MARC solver. The grid is a hexahedron grid over several layers, depending on the thickness of the strip. In practice single-layer models proved to represent a good time/benefit compromise. Machine and roll data are put in via a 2D-CAD system, in some cases via prefabricated masks or tables. The rolls rotate – they are defined as sliding bodies. As friction can be basically taken into consideration only through conversion calculations, friction is not often used in practice as it leads to relatively unfavourable and often also unrealistic results. Material data of the different steels are only taken into consideration with respect to their yield strength. Flow curves are assumed only of standard materials. It becomes clear here that such a computation cannot image the full scope of the bending process.

Continuous parametric data consistency from the 3D model of calculation models to the production drawing

Calibration path with quick-change stand

Formation flower

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M ay 2011

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