Functional product validation and optimization of technical systems in motion as a part of product lifecycle oriented tolerance management

• Applicant: Professor Dr.-Ing. Sandro Wartzack
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: from 2009 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 165053436

Within the two-year continuation of the research project (DFG-GZ: ME1029/16-1) the use of statistical tolerance calculations (tolerance analysis and tolerance synthesis) during the product development will be enhanced in order to enable the early validation and optimization of a technical system`s operational behavior. In this context, the integrated tolerance analysis of systems in motion was developed during the first two years of the research project. This approach enables the product developer to determine the time-depending effects of manufacturing-caused deviations and operation-depending deviations of a system in motion.The first aim of the research project`s continuation is the extension of the existing integrated tolerance analysis-approach towards more complex technical systems as well as the system`s complete operation time. Therefore, additional kinds of deviations have to be taken into account, including assembly-caused deviations as well as operation-depending deviations, which haven`t been considered yet. Due to the extension of the considered operation time interval (complete operation time instead of just one motion cycle) also operation-depending deviations can be taken into account which effects usually appear during much larger time intervals. Examples include wear and relaxation of parts during the system`s use. The consideration of interactions between the appearing deviations enables the product developer to quantify the effect of a single parameter on a functional key characteristic as well as the effects of the parameters among themselves. Especially in case of systems of higher complexity these interactions need to be taken into account.In general the product developer is more often faced with the problem of tolerance synthesis (the appropriate allocation of the functional key characteristic`s tolerance towards the single part`s characteristics) instead of tolerance analysis. So in order to use the achieved results of the project for this task, the developed integrated tolerance analysis should be transferred into an integrated tolerance synthesis. So the product developer will be able to determine the optimal tolerance allocation/specification, ensuring the system`s functionality at any point in time during the complete operation time by minimizing the costs resulting from the tolerance specification.Finally, the developed approaches on the integrated tolerance analysis and tolerance synthesis have to be formulated and visualized in an appropriate procedure. So the product developer can use this methodology to perform statistical tolerance analysis and synthesis systematically achieving reproducible und reliable results.

• DFG Programme: Research Grants