Posters
Come meet the poster presenters to ask them questions and discuss their work
We would like to invite you to come and see the posters at our upcoming conference. The posters will showcase a diverse range of research topics, and will give delegates an opportunity to engage with the authors and learn more about their work. Whether you are a seasoned researcher or simply curious about the latest developments in your field, we believe that the posters will offer something of interest to everyone. So please join us at the conference and take advantage of this opportunity to learn and engage with your peers in the academic community. We look forward to seeing you there!
PO242: Linking the microstructure with strain-life curves for improved utilization of the lightweight potential of thick-walled nodular cast iron
Christian Pittel, Research Associate, Fraunhofer Institute for Structural Durability and System Reliability LBF
Abstract
The assessment of the fatigue life of critical, highly stressed component areas is an important aspect in the design of thick-walled components for wind turbines made of nodular cast iron. With the demand for resource efficiency through lightweight construction combined with a certain capability to withstand extreme loads and misuses, this issue is becoming increasingly important. The fatigue life assessment gains importance when notches or deviations in the local microstructure are present. However, there are still gaps in the description of local strain-based material behaviour. For the design and local strain-based fatigue assessment of large cast components, possibilities to determine the service life as accurately as possible must be provided by standards and guidelines. The presentation aims to provide a wide range of material and fatigue data from one common source for general design interests. During research projects at the LBF, material properties for the trilinear approach strain-life curves and the elastic-plastic material behaviour of 8 different grades and different wall thicknesses have been derived. In addition, the influence of the statistical and geometric size effect on cyclic stress-strain and strain-life curves is discussed. For this purpose, 8 GJS grades with 29 microstructural variations are available. To describe the influence of the technological size effect, the characteristics of the microstructure, quasi-static parameters and process parameters from the casting process are taken into account. Based on these findings, the influences of the microstructure on the stress-strain and fatigue life curves are described. In addition, suggestions for scatter bands in the strain-based design approach are given to the designers of thick-walled GJS components. Furthermore, the methods for determining generally valid scatter bands from a larger number of strain-controlled fatigue tests are discussed.
