Brittle crack propagation/arrest behavior in steel plate – Part I: Model formulation

鋼材の脆性破面形態に関する数値シミュレーションと実験

“…At very near the plate surfaces it is no more possible for the crack to propagate in a brittle manner; uncracked ligaments are formed and they are fractured in ductile manner to form shear-lips on fracture surface. This phenomenon was modelled by Shibanuma et al 20,21) . They assumed that a depth of the zone where the plane strain condition is lost is equal to (1/3 )( / ) 2 , where is dynamic stress intensity factor and is yield stress of the material with strain-rate effect incorporated.…”

A Study of Brittle Crack Arrestability Test Method

“…따라서 최근의 대형선 박의 건조 시 소재의 파괴인성을 확보하는 것은 필수 요소가 되었다. 종래의 선박건조에 있어서는 사용되는 취성균열전파정지인성 측정법에 관한 연구 안 규 백 * ㆍ배 홍 열 ** ㆍ박 정 웅 ***, † 강재가 주로 50mm 미만의 강재가 적용되어서 두께 증가에 따른 불안전파괴 발생의 위험성에 대한 인식이 낮았으나, 최근 선박의 대형화에 따라 적용강재의 극후 물화가 급속하게 진행되어서 불안전파괴의 위험성이 증 가됨에 따라 파괴안전성확보를 위한 많은 연구가 수행 되었다 [11][12][13][14][15][16][17][18][19][20][21][22][23] . 또한, 극후물재에서 나타날수 있는 불안전 파괴의 방지를 위하여 최근 취성균열정지 성능이 우수 한 강재 (BCA강: Brittle Crack Arrest steel)가 국 내외 철강사에 의해서 개발되었다 24) .…”

3D Observation of Micro-cracks as Cleavage Fracture Initiation Site in Ferrite-pearlite Steel

“…Shibanuma et al recently proposed a prediction model of cleavage fracture toughness of ferrite-cementite steels, 22,23) based on the microscopic fracture initiation process. 3,[24][25][26] As a result of application of the model to the fracture toughness test of the steels having various size of microstructures, the prediction results showed good accuracy with the actual experimental ones.…”

“…1. Hiraide et al developed a model to predict fracture toughness of the ferrite-pearlite steel, 31) as a modification of the model proposed by Shibanuma et al 22,23) The model was based on the microscopic fracture process composed of three stages: (I) Micro-crack formation in shear at pearlite grain; (II) Crack propagation into ferrite matrix; (III) Crack propagation across ferrite grain boundary, as shown in Fig. 2.…”