10 Jul External test
Blaest is accredited to carry out both in-house tests as well as field tests.
The field test can be carried out indoors as well as outdoors. Blaest offers a wide variety of services as field tests:
- Natural frequencies
- Modal analysis
- Static proof test
- Fatigue proof test
- Post Fatigue Static Test
Test for determination of residual structural strength can also be carried out.
Field tests carried out at the client’s premises imply that both the client as well as Blaest contributes to the blade test. In general, the client will contribute with test rig, handling and installation of the blade, whereas Blaest will undertake the instrumentation and carry out the actual test.
Static tests may be carried out as a multipoint load application or a single point load application. Furthermore, the load may be applied in horizontal or vertical direction.
Figure 1 Example of Multipoint vertical outdoor static test (photo from IEC 61400-23)
The duration of a fatigue test may be several months. Activities as surveillance, inspection and calibration of the test setup will take place at regular intervals. Repair and maintenance of the test- and measuring equipment is also expected to take place during the test period. Depending on the possibilities of outsourcing activities without compromising the integrity of the test, a certain part of the test activities will be outsourced to sub supplier or to the client.
Figure 2 Fatigue test in a tent (photo from IEC 61400-23)
The staff from Blaest will perform surveillance of the test by means of web cameras and on-line network access to the data acquisition system.
Outdoors testing is an option. It will reduce the costs but also entail certain difficulties. Test- and measuring equipment must be protected against the environment, but also aspects as confidentiality and noise are to be a considered. Temperature changes and wind will also affect the results of the test. It is therefore necessary to measure, analyze and report the results taking these effects into account.