動的破壊靱性に及ぼす負荷速度の影響 : 環状切欠付丸棒試験片による検討

概要

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One of problems relating to the dynamic fracture toughness of heary section, structural steel plates is the effects of looding rate on it. The authors have studied experimentally on the dynamic fracture phenomena in high speed tensile test using notched round bar specimens. The results obtained were as follows. 1) The stress ratio of σ_<Net>/σ_Y has transition phenomerna against test temperature. This transition temperature shifts to higher side for higher notch acuity and for faster tensile rate. 2) An increase of σ_<Net>/σ_Y value for increasing tensile rate was smaller for fatigue cracked (FC) specimen than for machine notched (MN) specimen. While an increase of transition temperature was smaller for MN specimen than for FC specimen. 3) The critical dynamic COD value δ^d_c defined at fibrous crack initiation for both FC and MN specimens was observed to remain approximately constant up to tensile rate of 20m/sec and δ^d_c increased abrupthy for larger tensile rate than 30m/sec. 4) There are following relationships between transition temperatures for dynamic and static test for FC specimen. T^d_s-T_s(0.2)≒20 T^d_s=-40℃ T^d_J-T_J(10)≒30 T^d_J=-50℃ The authors can also estimate the transition temperature of FC specimen from the data of MN specimen.
社団法人溶接学会の論文
1981-04-05