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Numerical modeling and analysis of the influence of non-ideal boundary conditions on a mechanical press

 
: Riccio, Cleto
: Tehel, Robert

Neapel, 2018, 110 pp.
Neapel, Univ., Dipl.-Arb., 2018
English
Thesis
Fraunhofer IWU ()
forming machine; structural analysis; non-ideal boundary condition; FEM analysis; failure frame

Abstract
Forming machines are a fundamental component of large-scale production.They must meet the growing forces required during the transformation process of high-strength materials as well as high dynamic load peaks as a result of increases in the number of strokes and cutting and embossing forces during the forming of the higher-strength materials. In accordance with customer requirements and the maximum load projected therefrom, the presses are designed to be optimized according to maximum stress. FEM models based on ideal geometry and material data are used to check the design. At present, an increased failure of frame and drive assemblies of forming machines is to be found among the users, although the FEM calculations carried out confirm the fundamental correctness of the design. The reason for the failure of the assemblies, which was determined by the IWU in numerous experimental investigations in various presses, is probably due to non-ideal boundary conditions in the FEM calculation. The tolerances resulting from production and assembly, are wear-dependent. Wear can also be considered geometrically as a tolerance. It’s not taken into account in the FEM calculations and is at the center of this preliminary study. A list, categorization and visualization of selected standard state deviations as well as their exemplary calculation and simulation serves as a preparation and concretization of a comprehensive project for the investigation of the influence of standard deviation in the stresses of forming machines. The goal is to be able to qualify by means of sensitivity analyses of critical tolerance groups, FEM analyses and to derive tolerant recommendations as well as monitoring concepts for presses and to allow tolerances and safety factors to be qualified in order to generate the basis for an economic weighting of standard state deviations.

: http://publica.fraunhofer.de/documents/N-484536.html