Approach for the Visualization of Geometric Uncertainty of Assemblies in CAD-Systems

Abstract

Abstract:The foundation for the development of successful products is based on knowledge about the characteristics of the product throughout the entire product life cycle. However, uncertainties can arise over the life cycle. These characteristics simultaneously influence each other and therefore the characteristics of the product in the product development and usage phases need to be identified. This uncertainty can have negative economic consequences, such as functional failures or oversizing. In this paper a concept for the visualization of geometric uncertainty of assemblies in CAD-Systems based on ontologies will be presented. This is an approach for visualizing various types of uncertainty of different product life cycle phases to control uncertainty in load-carrying systems during virtual product development. The concept is a part of the research activities of the CRC 805 (Collaborative Research Center 805).

Analysis, Quantification and Evaluation of Uncertainty

“…As to the definitions it is determinated which tests are necessary, how and in which quantity the product must be manufactured and at what time it needs maintenance. Uncertainty may have negative effects on decisions, which can lead to over-sizing, unfulfilled customer demands and unforeseen failures [74]. As pointed out by Anderl et al [6], software applications used in the engineering context rarely consider uncertainty quantification, which partly explains the lack of awareness about uncertainty by designers.…”

“…A typical example is the tolerance stacking of geometric manufacturing tolerances. In order to make uncertainty information about afflicted part properties available throughout the entire assembly, this information is attached to elements of the topology of the 3D CAD-model as attributes described by Product Manufacturing Information (PMI) [74]. PMI comprises non-geometric information and aims at providing annotations for 3D geometric models [74].…”

“…In order to make uncertainty information about afflicted part properties available throughout the entire assembly, this information is attached to elements of the topology of the 3D CAD-model as attributes described by Product Manufacturing Information (PMI) [74]. PMI comprises non-geometric information and aims at providing annotations for 3D geometric models [74]. It is typically used to describe additional properties to define the product geometry more precisely, primarily for manufacturing purposes such as manufacturing tolerances.…”

“…It is typically used to describe additional properties to define the product geometry more precisely, primarily for manufacturing purposes such as manufacturing tolerances. PMI also refers to any data that is linked to geometry or topology of a 3D CAD-model [74].…”

“…The body-attribute serves as an individual part specific information carrier and contains all information from face-and edge-attributes, that belong to an entire body. Through the configuration of individual parts via assembly constraints, the bodyattributes associate corresponding parts with one another and enable bidirectional PMI exchange [74]. One individual part contains exactly one body-attribute but multiple face-and edge-attributes; these comprise uncertainty information mapped into a specific PMI being associated with the afflicted object property.…”