André Sprenger

Ontology-based Information Model for the Exchange of Uncertainty in Load Carrying Structures

Knowledge about future process properties is crucial for the development of safe and economic products with load carrying structures. Real processes are influenced by uncertainty what causes scattering and deviation from assumed values. As a consequence, products are often oversized or even product failures can occur. To control uncertainty, extensive knowledge about future processes is necessary in the development process. This paper shows an approach for the representation of uncertainty in production-and usage-processes, according to scattering properties and their cause and effect relations. This approach is used as a common platform for storing, locating, comparing and reuse of knowledge about uncertain properties and their relations. The core of the proposed approach is an ontology-based information model with the ability to represent different levels of trusted information in relation to process parameters and cause and effect relations.

Consideration of Uncertainty in Virtual Product Design

In design, manufacturing and usage of technical products uncertainty arises according to process properties and results in influence of products properties. In current CAD-systems, where products and product properties are presented, uncertainty is not considered yet. In this paper, we propose a new enhanced concept for the visualization of information about uncertainty in CAD-systems. The presentation of uncertainty is realized on basis of three-dimensional parametric models in a CAD-system and an implemented uncertainty-browser. The uncertainty-browser acts as a graphical user interface to categorize information about uncertainty, the processes and product properties. Beyond that, information about uncertainty will be visualized as annotations referring to chosen properties. Being aware of information about uncertainty during product design, the engineer is able to improve his product. The representation of uncertainty is based on an ontology based information system for supporting the collection and categorization of information about processes, products and uncertainty.Copyright

Approach for Visualization of Uncertainty in CAD-Systems Based on Ontologies

In this paper an approach for controlling uncertainties in load-carrying systems in virtual product development during the phase of product design will be presented. In design, manufacturing and usage of technical products uncertainties arise according to process properties and they influence products properties. Many of these properties impact each other. These facts lead to deviation of expected property values which are shown for example in the approximation of stress and strength. In cases of load carrying systems misjudgment can lead to disastrous consequences. In this paper an approach for the visualization of information about uncertainty in load-carrying systems in CAD (Computer Aided Design)-systems within the Collaborative Research Center (CRC) 805: “Control of Uncertainty in Load-Carrying Systems in Mechanical Engineering” funded by the DFG (Deutsche Forschungsgemeinschaft) will be described. The representation of the properties’ interdependency is to be expressed by an ontology based system. The visualization of the properties and the information about uncertainty is demonstrated in a CAD-system.

Representation, Presentation and Visualization of Uncertainty

Uncertainty in the design process impacts performance parameters of products which are a major problem in the development of highly optimized load bearing systems. Typically, the information flow in the design process is a one way process from the design to subsequent product life cycle phases. Uncertainty about product properties leads to less economic and less safe products. In this paper an innovative approach to enable modeling and communication of uncertain properties along the product life cycle and the sophisticated presentation and visualization of these uncertainties is proposed. This approach is based on a three layer concept including a representation layer, a presentation layer and a visualization layer. The approach enables the visualization of a broad spectrum of process and product properties with respect to different specifications of each property e.g. single values, intervals, fuzziness and stochastic measures which may occur along the product life cycle.

Product Life Cycle Oriented Representation of Uncertainty

In this paper an innovative approach is presented, which enables modeling and exchanging information about the uncertainty of product properties along the product life cycle providing improvement for product development. A system which is called “COPE” (Collaborative Ontology-based Property Engineering System) is proposed, which uses the advantages of an ontology-based approach. The proposed system captures information about product properties and the circumstances as statistic of fuzzy information, and combines them with the product model, to provide information about the actual and possible future product life cycle processes and the future product properties to the stakeholders.

Methodology for Estimation of Life Cycle Orientated Optimizatation Measures of Investment Goods

A manufacturer of any kind of product has to be in contrast to competitive to survive on market. A major point to win a customer over is the arrangements of costs. In investment goods industry asset cost are just the tip of the iceberg. Most of their costs accrue by use. Because of that it is important to overview the whole costs of the product life cycle. Product life cycle costs describe the cost of a product over its whole life. This includes all expenses from development, production and use to recycling and refers to manufacturer and customer equally. The majority of costs are determined in the stages of product development. As a manufacturer of complex investment goods (e.g. machine for production) the question of new development investments has to be answered. There are three important dimensions to consider. These dimensions concern the right part of product for improvement, the right kinds of costs and the owner of these costs. In detail they have to decide which part of product should be improved to get the main effect concerning reduction of life cycle costs. But in that case it is also important to know what kinds of costs of the chosen part have to be reduced (for example energy cost, cost for maintenance or repair). The third dimension in case of product life cycle costs aims at the owner of the cost, manufacturer or customer. This is a problem when new developments cause savings on one side but expenses for the other. In that context the best leverage of these combinations is searched for which means that exactly this kind of costs has to be identified, whose savings get the biggest benefit in relation to necessary expenses. This paper presents an approach to address this problem. For the pre-selection of possible functions established methods derived from product development are used in this context. Afterwards a procedure of quantification is presented. Calculation and rating of new defined management ratios provide the biggest leverage in order to reduce the product life cycle costs. This approach represents an instrument for manufacturer’s business of investment goods to make decisions about their future investments in the field of product development.Copyright