Geometric Modelling of Sheet Metal Stampings

Abstract

<p>A technique has been developed for the assessment of the magnitude and direction of the principal finite strains from measurements made on a deformed pair of lines. The analytical procedure leads to the establishment of a symmetric second order tensor which is not one of the classical large deformation tensor defined in many Continuum Mechanics texts, but is much simpler in form and readily applicable to the determination of natural strains in sheet metal forming operations.</p> <p>Another aspect of this work has been an attempt to provide a new method (Geometric Modelling) for blank development and the investigation of possible strain distributions in forming sheet metal components. It is a computer technique simulating the traditional manual calculations performed by experienced tool designers.</p> <p>The present work describes the formulation of the fundamental theory of the method and the basic geometric assumptions which are employed. Two particular examples have been considered; one is forming a sheet on a smoothly analytically defined surface and the other is forming the corner section of an automotive stamping.</p> <p>The detailed analytical procedure is implemented in FORTRAN code. The analysis has been performed without access to advanced computer graphics. However; the results suggest that the basic approach is feasible and that future modelling using interactive computer graphics may well be attainable.</p>