@article{oai:kyutech.repo.nii.ac.jp:00006772,
 author = {Ikeda,  Tomohiro and Noda, Nao-Aki and 野田, 尚昭 and Sano, Yoshikazu and 佐野, 義一},
 journal = {Engineering Fracture Mechanics},
 month = {Nov},
 note = {In this study, notch strength σ B notch was studied for a wide range of testing speed and temperature in comparison with the static tensile strength at room temperature σ B, RT smooth. High–speed tensile tests were conducted on high–Si ductile cast iron, conventional ferrite–pearlite ductile cast iron, and fully pearlitic ductile cast iron at a stroke speed ranging between 8.5 × 10−3–2.7 × 102 mm/s (strain rate of 2.1 × 10−4–1.8 × 101 s−1) and temperature ranging between −180°C–22°C. Then, σ B notch and σ B,RT smooth  were compared in terms of the strain rate–temperature parameter R = T ln (A/ ) to evaluate the combined influence of the strain rate   and temperature T. It was found that the notch strength σ B notch can be expressed as a unique master curve in terms of R parameter for each material. Then, a notch–strengthening threshold criterion R ≧ Rth was proposed to describe the lowest service temperature and highest strain rate that can be applied to the structural components. Under the condition R ≧ Rth, σ B notch  is always larger than σ B,RT smooth , and therefore, notched components can be used safely. In other words, if R ≧ Rth, σ B,RT smooth can be used to evaluate the notched components in machine design to prevent instantaneous fractures.},
 pages = {75--88},
 title = {Conditions for notch strength to be higher than static tensile strength in high–strength ductile cast iron},
 volume = {206},
 year = {2018},
 yomi = {ノダ, ナオアキ and サノ, ヨシカズ}
}