Thermo-elastic optimization for additively manufactured turbo machinery components

Aircraft engines are subject to increasing efficiency requirements. Additive manufacturing (AM) offers light weight potential to reach these requirements. The combination of AM and topology optimization (TO) is known to have great light weight potential. We present a case study of a turbine guide vane, of which the interior is optimized in order to reduce weight but maintain required aerodynamic functionality. The critical loading condition for a guide vane is take-off, where thermal stress occurs due to transient heat transfer. Thus, the thermal stress should be considered in the optimization. The workflow is consists of TO using OptiStruct, remeshing with OSSmooth followed directly by a shape optimization. Manual geometry generation after TO is not wanted since it is time consuming and may reduce the geometric optimality. Topology optimization with a thermo-elastic load case is performed and two approaches are evaluated on the basis of simplified guide vane geometry. First, the definition of compliance in a thermo-elastic load case is looked at. Then, the min. compliance setup is compared to min. mass setup. The results of a thermo-elastic TO are compared to TO with a mechanical load case. The results are evaluated in terms of stress level and mass reduction. At the end, the workflow is applied to real guide vane geometry. The results are evaluated in a transient thermo-elastic FE analysis.

The Author

Mr. Joona Seppälä
Research Associate
Technische Universität München