Introduction:
OptiDAT is the database from the OPTIMAT BLADES project. The database is not directly meant for certification purposes, but the information and methodology is used for guidelines for testing of wind turbine blade materials.
Contents:
The OptiDAT database contains results of various tests on some 3000 coupons. In terms of testing time, this is 40.000 hours, the total number of fatigue cycles approximates 900 million. Tests were performed on two material systems; both are glass-fibre reinforced epoxy, but the resin systems are slightly different. The majority of the tests have been performed on the standard OPTIMAT geometries for Unidirectional and Multidirectional material. The focus is on fatigue results, and test results for various loading conditions can be found in the database, describing material behaviour in fatigue, static, bi-axial (tubular and cruciform), repairs, residual strength, variable amplitude, extreme conditions, thick laminates, shear loading, 4-point bending, loading in transverse direction, etc. Detailed information is also available on the thermal expansion coefficients, and for most plates, the fibre volume fraction and glass transition temperatures were measured and reported.
Lay-out:
The database is constructed in a spreadsheet format (MS Excel). This is for historical reasons as well as for compatibility.
All the test results are reported in a single worksheet. Every row in the worksheet represents a test; every column contains data on various aspects of the test; coupon identification, laminate, dimensions, test type, test results. Although some 100 columns are reserved for detailed information on the various test types, further information may be required by the user. One column contains a reference to the various (ca. 150) technical reports with further information on the particular test. In these reports, information can be found which is, at the time, not feasible to include in the database (without making it difficult to handle), such as stress-strain diagrams, a thorough description of the test set-up, and images of the coupons failure modes.
The database contains other sheets, with information on how to use the database, plate, geometry, and test type details, and contact information of the project participants. Also, the FACT database is included in a separate sheet.
This set-up allows for quick comparison of test results.
Storage:
During the OPTIMAT project, the OptiDAT database was used for storage of the test results. The participating laboratories submitted the data as soon as possible after completion of the tests. Ensuring consistency, a data submission sheet was available for the contributing partners. Thus, all test results were available for review and further analysis during the test programme, rather than at the end of the programme. The database was uploaded to the OPTIMAT Web site after each addition of test data.
Progress tracking
The availability of the results facilitated tracking the test progress. The database included several progress tracking features.
The Manufacturing and Delivery sheet, from the projects main supplier, LM Glasfiber A.G., was included in the database. This showed for each batch of coupons the shipment date, recipient, coupon type, plate number, etc. The information was related to the data in to the database. Thus, for each delivered batch, the user could see directly how many of the coupons had already been tested hence, how many should be left.
Also, the information from each Task Groups Detailed Plan of Action was included, describing the test plan. This information was also linked to the test results already in the database, giving a detailed overview of the progress.
Finally, the number of records, test hours, or number of cycles, could be visualised automatically using an interactive chart, giving a quick overview of the cumulative test results.
Tools:
The database contains some pre-programmed tools, to increase user-friendliness. The vast amount of columns and rows can be viewed in various modes using a specialised toolbar. This allows the user to limit the visible records to a particular test type, selection of columns, or both. A user-defined column view can also be set.
To display fatigue data quickly, the database is equipped with a plot tool, which allows the construction of an S-N diagram using a selection of data. The result is a chart with the selected data, and a separate sheet with a copy of the selected records, for further processing.
Prospects:
OptiDAT is available from www.kc-wmc.nl from May 2006 for a small maintenance fee. It is freely available for OPTIMAT members and students). A subscriber set-up warrants regular updates, as well as inventorising the user-population, which helps tailoring the data to user requests. It will be expanded with the results from WP 3 of UPWIND.