大きな圧縮予歪を受けた鋼材の破壊靭性に関する一考察

概要

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When buckling collapse takes place in structural steel members, large compressive strain deteriorates the ductility and fracture toughness of the material at the concave side of buckling deflection. Therefore cracks may easily initiate and propagate at the concave (compressive) side of buckling deflection. In this paper, in order to quantify the deteriorating effect of the large compressive strain on the fracture toughness of steels, a series of CTOD tests were performed on three kinds of steels (490MPa-class high tensile steel plates). As a result of the investigations described above, the following conclusions were obtained: (1) Fracture toughness (δc) is deteriorated extremely and transition temperature shifts to very higher side with increasing the compressive prestrain. (2) From investigation results of brittle fracture surfaces both of CTOD specimens and V-notch Charpy impact test specimens, regardless of the kinds of the steels, the rugged fracture surfaces become flat with increasing the compressive prestrain. (3) The equations to be able to estimate the fracture toughness of the steels experienced large compressive strain by using the results of V-notch Charpy impact test and tension test for the steels prestrained in compression are obtained.
社団法人日本船舶海洋工学会の論文
2001-08-31