Robust design and reduced lead-time are key issues in the general field of product development today. The meaning of KEE (Knowledge Enabled Engineering) can be generalized as a process to customize computer aided engineering systems to reduce the lead time for routine engineering work as well as securing the design “know-how” for specific components. As a part of the KEE development at Volvo Aero, methods and rules are defined and implemented in applications to secure repeatability and aid product developers in their routines.
The aim of this thesis is to study and improve a knowledge based application programmed in Knowledge Fusion that describes an aero based definition in CAD, and to secure its downstream functionality.
The problem statement is identified through surveys and an application study. Due to high complexity and surface inconsistencies, problems can arise in downstream work. Section curve definition is a problem since the methods used, are creating curves segmented by all points used as input. This leads to a complex and over-defined section curve with irregular curvature distribution. When the section curves are used to create the blade surface, the complexity and curvature peaks are inherited.
From case studies and a CAD functionality study, a new approximation method is found for section curve definition, making it possible to reduce the number of segments. Since the spline complexity and curvature interference are found to be closely related, the new approximation method reduces both. New blade surface routines have been programmed where blade section curves are constructed with this approximation functionality. Reduced number of spline segments contributes to a smoother end surface with less curvature inconsistencies, more useful for further downstream work.
Although the new application for modeling aero blade profiles requires further evaluation and data handling improvements, the first generated blade profiles demonstrates that an improved surface quality with lowered complexity and low deviation from aero point definition is possible. The availability of the spline approximation functionality also opens new possibilities for future project implementations and model improvements.
Author: Olofsson, Anders
Source: Lulea University of Technology
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