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Kristoffer Berg

Kristoffer Berg
Condition Monitoring and Fault Diagnosis Applications
Fakultet for teknologi og realfag
10. desember 2018

Finite Element Analysis of an Electric powertrain for Condition Monitoring and Fault Diagnosis Applications

The project was carried out summer of 2018, as part of an ongoing PhD research project on condition monitoring and fault diagnosis applications. The tasks involved building a realistic model in Comsol to later utilize in different FEM simulations.

The project was carried out the summer of 2018, to assist PhD student Jagath Senanayaka with research project on condition monitoring and fault diagnosis applications.  The objective of this project was to develop an electromechanical FEM for fault diagnosis applications simulating faults of the mechanical components. 

Implementing and building the Comsol-model

To ensure that the Comsol-model did not get to complex in the start, a model for the gearbox and motor where build separately. While working on the mesh, small errors like "intersecting elements" and "to small edges" occurred and where improved in the SolidWorks model. For both the models there where added a fixed rotation on one of the shafts to verify that the gear-definition and the constrains where defined in the correct way.

The next step in the project concerned making a realistic model of bearings, where errors like a damage in one of the traces should be produced. This turned out to be far more complex and was therefore a time-consuming process. In the end a bearing with inner- and outer-ring, balls and ball-cage where modeled and simulated in Comsol, where the components moved by use of contact constraint with no slip and gravity. Simulation of this bearing takes a long time to simulate due to the contact constraint, therefore a lot of time where spent trying to reduce the complexity of the simulation. This was done mainly by adjusting different settings in the contact and friction constraints and also fine tuning the step-time for the simulation.

 

Outcome of the project

Different 3D CAD models were imported from SolidWorks into Comsol. A FEM model was defined with constraints corresponding to physical constrains between each individual component. The main focus of the project ended with a FEM simulation of bearing, but due to the complexity a good result was not achieved, also resulting in the electromechanical FEM not being completed. Irrespectively, the work done forms a good foundation for further investigations in the subject.