Virtual End of Line Test - Use of Dynamic Models in Digitalized Functional Testing

• Applicant: Professor Dr.-Ing. Christian Brecher
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 528667767

An End of Line Test (EoLT) is used in almost all series production gearboxes to monitor the quality of the finished products. Among other things, noise emissions is used as test criteria to assess the condition of the gear unit. If predefined limit values are exceeded during the test, the corresponding gearbox must be sorted out and reconditioned. This is very time-consuming and cost-intensive. The overall objective of this project is therefore to develop a simulation methodology that allows the amount of gearboxes that have to be sorted out in the EoLT to be reduced. Before assembling, a simulation of the excitation behavior is to be carried out with the gears to be installed. In order to be able to correctly represent the resulting noise emissions, the entire system must be taken into account in the simulation. Simulation approaches that have existed to date for this purpose require a great effort of calculation time and therefore do not allow application parallel to a production and assembly line. These currently existing models originate from the design of gearboxes. They are therefore able to take into account adjustments to all geometric elements. However, this is not a requirement that series production places on a model. In a series production, all geometric elements of the gearbox are defined. Here, a simulation model only has to be able to react to geometric deviations resulting from the tolerance of the production. Similarly, only deviations on functional surfaces are relevant here, which further reduces the number of inputs that the model must be able to take into account. These changed requirements for inputs of geometric changes are to be used to develop a new type of model in four steps. It should be able to be used in parallel with production and assembly lines due to a significantly shorter calculation time. A large number of quantities for the evaluation of the excitation leading to the emission of noise exists. Therefore, the first step is to determine the evaluation quantity that is most appropriate for the design of the model. The second step is used to identify the manufacturing deviations that, to the extent of their occurrence, have a significant effect on the excitation behavior of the gearbox. For example, deviations on functional surfaces in the power flow will have a dominant influence on the excitation behavior. Thus, it is determined which deviations are necessary as input for the simulation model. In the third and fourth step, performance optimized modeling methodologies are first selected for the components that do not require deviation inputs. Subsequently, the selection is also made for components whose deviations are to be considered as inputs. Finally, the generated submodels are assembled to the overall model.

• DFG Programme: Research Grants