Development of an expert system interface for the automated analysis of the sheet drawing metal forming process using finite element analysis techniques

摘要

The objective of the work presented in this thesis was to develop an expert system for sheetudmetal forming. In doing so an examination, of implicit and explicit Finite Element Analysisud(FE.A) codes and methodologies was conducted. Guidelines as to how best to carry outudsimulations of sheet drawing, were developed. Work was conducted into deep drawing andudshallow drawing of non complex shapes, because of the many analytical, and empirical studiesudconducted on cup and box drawn shapes. The process parameters effecting drawing of complexudparts are present in drawing of non complex parts such as cup and box shapes. A valuable insightudinto drawing of complex parts can be attained economically, with the proposed study of drawingudof non complex parts, such as cup and box shapes. Modelling and solution variables present inudimplicit and explicit F.E.A. codes are explored by the modelling of non complex parts such asudcup and box shapes.udDeep drawing is a common process used in the manufacture of auto body components;udcans, cups, bathtubs, sinks, and other similar items by drawing rolled sheets into there finaludgeometric form. Configuration of a new deep drawing process is highly empirical with manyudparameters determined by trial and error. Large deformation numerical Finite Element Analysisudof the deep drawing process can be applied to shorten the process reconfiguration time andudremove the expense of trial production runs of parts. In the research work reported in this thesisudparametric studies are performed on critical deep drawing parameters. The findings are presentedudand are incorporated into the Expert System for Metal forming.udMaterial non linearity is introduced by a description of drawing blank material plasticity.udThe discussion on plasticity introduces rate independent material behaviour models, typicallyudused to model the behaviour of Steel and Aluminium Blanks. The Taguchi method ofudexperiment design and results analysis is applied to develop strategies for the design of bestudpractice finite element simulation of cup drawing. The expert system for cup drawing containuddomain knowledge in the form of analytical model and dedicated automatic development ofudFinite Element Analysis simulations which is developed in ANSYS command script files. Theudcontrol aspects of the expert system utilises goal and data driven reasoning within the controludalgorithm. A blackboard architecture to the expert system is promoted with the ANSYSudAdvanced Parametric Design Language (APDL) macro programming language.