Computerunterstuetztes 'Teach-in' fuer Bridgman-Giessanlagen Schlussbericht

A series of software tools has been developed for numerical process optimization with respect to structure properties of directionally solidified turbine blades. This software is part of the 3D-FE-code CASTS and includes the following moduls: - A quality analysis program which assesses structure properties of a component: This program calculates scalar values related to material qualities of a turbine blade. Different quality requirements for a component - determined by production process and operating conditions, including specific restrictions (e.g. low microporosity, planar interface) - can be quantified. - A new data structure for the thermal FE-analysis which allows variable sets of process parameters, e.g. transient heater temperatures or withdrawal speed. - An automatic optimization loop: Numerical variation of process parameters taking into account specific process restrictions improves quality of the casting. In order to tackle this complex problem the following algorithms have been implemented and applied: - gradient methods, coupled with a quadratic line search - conjugate gradient method - evolution strategies - quasi Newtonian algorithm. Using an evolution strategy, the solidification time of a directionally solidified dummy blade has been minimized. The withdrawal profile to be optimized was defined by 15 parameters. Dummy blades have been cast in order to demonstrate the performance of this optimization exercise. (orig.)SIGLEAvailable from TIB Hannover: F96B1780+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman