DNV has performed experimental modal analysis on the Skysmart 2 tracker installed in Arctech Solar’s factory located in Jiangsu, China The project included, designing and executing a physical modal test using modal hammers and accelerometers and analyzing the test results and providing mode shapes, frequencies and damping ratios for the tracker’s main modes of vibration including the first and second twist modes, heave mode and sway mode. Having experimental measurements of the modal properties has provided a reliable basis for the customer to determine dynamic wind loads used in the design of the Skysmart 2 tracker.
Three key benefits
- Experimental reliable measurements of the tracker’s mode shapes were provided
- Test results were made available in a timely and reliable manner. The test was performed in less than a day and the results were provided soon after
- Natural frequencies and damping ratios were provided for the first ten modes of vibration for the tracker
About the customer
Founded in 2009, Arctech Solar is one of the world's leading manufacturers and solution providers of solar tracking, racking and Building Integrated Photovoltaics (BIPV) systems with over 800 employees worldwide. It is headquartered in Kunshan, Jiangsu Province of China, with its global business division and manufacturing base located in Shanghai and Changzhou respectively.
By the end of 2019, Arctech Solar had installed a cumulative capacity of around 24 GW and had successfully executed approximately 900 projects in 24 countries. Arctech Solar has been ranked among the top 5 tracker suppliers for the global PV market in the past 4 years.
The customer challenge
Arctech Solar required measurements for the natural frequencies and damping ratios of the main vibration modes of the Skysmart 2 tracker to be able to validate their design assumptions with respect to their dynamic wind load calculations.
DNV designed an experimental program that was simple and easy to perform. The test was completed in Arctech’s factory in less than a day. The test set-up included installing accelerometers in suitable locations on the tracker and applying impulse forces using a modal hammer along the tracker. The test results were analyzed and delivered and included mode shapes, natural frequencies and damping ratios.
Benefits to the customer
Determining damping ratios of different vibration modes of trackers using theoretical or numerical methods is challenging and may not be adequately accurate as simplifying assumptions need to be considered. Having experimental measurements of the modal properties provided a reliable basis for determining dynamic wind loads used in the design of the Skysmart 2 tracker.