Calculation of Dynamic Wind Loads on Heliostats Using FEM and Multibody Dynamics

Kurzfassung

At the German Aerospace Center’s (DLR) Institute of Solar Research, a new heliostat is being developed with the promise of bringing down the cost of heliostats by more than 20%. The main features in which this heliostat distinguishes itself from other heliostats is in its low part-count and in its size, as its mirror is only 2 m². This thesis describes the creation of a complex Finite Element Method (FEM) model for stress analyses, then making two simplified models for long-duration studies, which are computationally efficient. Their modeling methods were radically different, one being a multibody model while the other one a FEM shell element model. Only the FEM model led to results of good agreement with the complex model. With this simplified model, the timestamps of maximum deformations can be determined when loaded by a wind load time series that was gained from a wind tunnel test. With the obtained results, a Dynamic Load Factor (DLF) is determined to measure the impact of dynamic loads compared to static ones. Finally, stresses at critical timestamps from the long-duration study are analyzed with the complex model to provide detailed insights into the heliostat’s performance.