Challenge:
Design modifications of the original hub were necessary due to significant increase in both the standard operational loads and the extreme load magnitudes e.g. for off-shore applications and for longer wings. The size of the wind turbines increased by a factor of 10 whereas the capacity increased by 1000 over the last 20 years.
The application example of a wind turbine hub demonstrates how engineers efficiently manage increasing external loading requirements as well as achieve weight reduction and increased stiffness at the same time.
Available design space
Solution: Topology and shape optimization with SIMULIA Tosca Structure
Topology optimization is applied to obtain a new optimized structural design with lower weight and higher stiffness. Based on the available design space Tosca Structure.topology iteratively removes material and redistributes material in the topology optimization process.
Tosca Structure.topology derives a new structural design which optimally carries the loads.
Symmetry and casting constraints are considered during the automated iterative optimization process ensuring a simple implementation of the new design proposal in the further development process.
Additionally, a shape optimization using Tosca Structure.shape is run after evaluating the new topology optimized design. Tosca Structure.shape employs small but essential design changes at the surfaces of the components leading to a significant reduction of stress peaks.
Topology optimized result with reduced weight
Validation run of new design – showing stress distribution
Shape optimization result with reduced stress peaks
Benefit:
Using Tosca optimization yields a weight reduction of the hub and an increase in the total component stiffness. The reduction of the stress peaks led to an improved durability of the component.
Manufacturing conditions were regarded during the optimization process and the 1st prototype passed all verifications.Additional cost savings could be achieved due to the excellent new structural hub design: material savings, easier transportation, and assembly processes.
The integration of Tosca Structure into the product development process resulted in a significantly improved design and an overall shorter development time of the wind turbine hub.
Final optimized structure: Lightweight, stiff, and durable design
