Images courtesy of VERGNET S.A. & Nesys Engineering
A couple of weeks ago at the Siemens PLM Connection Europe event, I sat in a presentation on wind turbine design that (no pun intended) blew me away. Sorry for the delayed post but I just got approval to share these images with you.
Nesys Engineering, a small FEA firm, presented on their use of NX Advanced Simulation on wind turbine design. Their client for this case study was VERGNET S.A., France’s only manufacturer of wind turbines.
These images show a rotor hub – a casting part that weights just 4 tons! Fatigue is a big concern so analysis plays a key role in its design. Nesys uses NX for pre- and post- processing as well as Femap.
Nesys General Manager Emmanuel Crespin highlighted how the use of synchronous technology in NX 6 enabled them to reduce the time needed to build the FEA model.
“Thanks to the use of the new synchronous technology in NX 6 for defeaturing and quick meshing we were able to reduce our time by 70%.”
Before synchronous technology, they had to mesh all faces and fill, a task that could take more than 4 days in the past. ST allowed them to generate the mesh directly. (For those analysts out there, they noted there were 250,000 Tetra10 elements and 400,000 nodes).
These wind turbines are self-erecting and measure 70m (230 feet) high with a 62m (203 feet) rotor. In total, they are 130 tons. They run for 20 years at an average frequency of .6 Hz. So Nesys identified four loading conditions to analyze: fatigue, service loading, extreme loading and erection.
Here is a view of the rotor hub as it connects to the main assembly, highlighting the linear analysis Nesys did with NX Nastran’s 3D iterative solver. The analysis tested multiple extreme load conditions and multiple fatigue unit load cases.
Nesys also noted that the NX Nastran 3D Iterative Solver with shaved 55% off the solution time on this analysis. The analysis took just 45 minutes for seven load cases.
Nesys said the key features they leverage in NX 6 Simulation are: bolt tightening, non-linear for plasticity, contact/friction for linear statistics and pre-stressed normal modes.
In addition, they used Femap’s API to automate an analysis sequence and post process. They had to show fatigue over 20-years and the program enabled them to run it on 15,000 files.
Click here to check out the installation of one of these wind turbines from VERGNET’s website.