FSReman - Functional modeling of bolted joints under uncertain product conditions for remanufacturing

• Applicants: Professorin Dr.-Ing. Gisela Lanza; Professor Dr.-Ing. Sven Matthiesen
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 525034540

Remanufacturing, the most important procedure on the way to the circular economy, deals with the reprocessing of used products and product parts. Due to their detachability, bolt connections represent a central element for connections in the field of remanufacturing. The condition of the bolt connection determines the functionality of the reassembled product. Corroded or even damaged bolt connections can, on the one hand, make the unscrewing process more difficult, and, on the other hand, there is a risk of permanent damage to the internal threads due to an unfavorable choice of process parameters. Drilling out and inserting new threads is - if at all possible - expensive and time-consuming. Therefore, a function-oriented statement regarding the remaining load-bearing capacity when retightening using a new bolt is necessary. However, this is not possible according to the current state of research. The aim of this project is the data-driven functional modeling of bolted joints under uncertain product conditions. For this purpose, a functional modeling of bolted joints is to be carried out in this project. Remanufacturing comprises the disassembly process of a corroded bolt from a corroded thread and a downstream screw-in process of a new bolt into the thread of the remanufactured used part. Process and product data are recorded and a functional model of the bolt connection is derived for reassembly. The result of this project is a validated functional model for predicting functionally relevant variables, namely the load-bearing capacity of the remanufactured bolted joint and the thread friction coefficient during tightening, as well as the method for model development. The resulting functional model is based on existing process knowledge and known models. Subsequently, the functional model will be further developed using the empirical database collected in this project, consisting of process and product data.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Florian Stamer