Linking the microstructure with strain-life curves for improved utilization of the lightweight potential of thick-walled nodular cast iron

• Published in: Journal of physics. Conference series Vol. 2745; no. 1; pp. 12021 - 12040
• Main Authors: Pittel, C, Niewiadomski, J, Bleicher, C
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.04.2024
• Subjects: Cast iron; Design; Fatigue life assessment; Life assessment; Lightweight; Material properties; Microstructure; Nodular cast iron; Nodular iron; Particle density (concentration); Research projects; Size effects; Strain; Tensile strength; Thick walls; Weight reduction; Wind turbines
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/2745/1/012021

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 design combined with a certain capability to withstand extreme loads and special events, this issue is becoming increasingly important. 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 fatigue life as accurately as possible must be provided by standards and guidelines. The paper aims to provide a wide range of material and fatigue data from one common source for general design interests. During research projects at Fraunhofer LBF, material properties for the P RAM -based fatigue life assessment and the elastic-plastic material behaviour have been derived from 9 nodular cast iron grades with 44 microstructural variations. To describe the influence of the technological size effect on cyclic stress-strain and P RAM -N curves the quasi-static parameters (tensile strength and elongation at break) and the microstructure (nodularity and graphite particle density) are considered. In addition, suggestions for scatter bands in the strain-based design approach are given to the designers of thick-walled GJS components.