Effects of loading rate on the local cleavage fracture stress σf in notched specimens

	Effects of loading rate on the local cleavage fracture stress σf in notched specimens
	Wang, G.Z.; Wang, Y.L.; Chen, J.H.
	2005
会议名称	11th International Conference on Fracture 2005, ICF11
会议录名称	11th International Conference on Fracture 2005, ICF11
卷号	5
页码	3678-3683
会议日期	March 20, 2005 - March 25, 2005
会议地点	Turin, Italy
出版者	International Congress on Fracture
摘要	Four point bending (4PB) notched specimens with different notch sizes are tested at various loading rates at a temperature of -110°C for a C-Mn steel. An elastic-plastic finite element method (FEM) is used to determine the stress distributions ahead of notches. By accurately measuring the distances of the cleavage initiation sites from the notch roots, the local cleavage fracture stress σf is measured, and the effects of loading rate and notch size on σf are investigated. The results show that the local cleavage fracture stress σf does not essentially change with loading rate and notch size. The reason for this is that the cleavage micromechanism does not essentially change in the different specimens at various loading rates. For the steel with low critical plastic strain for fracture initiation in this work, the cleavage micromechanism involves competition of two critical events of crack propagation and crack nucleation in the high stress and strain volume ahead of notch root. For the tested steel, the critical events in the specimens which the cleavages are directly initiated at the notch tips are mainly the propagation of a ferrite grain-sized crack controlled by tensile stress, and the critical events in the specimens which the cleavages are initiated at a distance from the notch root are mainly crack nucleation controlled by plastic strain. The large scatter of σf and notch toughness are mainly caused by the different critical events in different specimens. The measured σf values and notch toughness corresponding to the critical event of crack propagation are lower than that of crack nucleation.
关键词	Crack propagation Elastoplasticity Fracture Manganese alloys Manganese steel Nucleation Plastic deformation Steel testing Stress analysis Cleavage fracture Critical plastic strain Elastic-plastic finite element method Four point bending Fracture initiation Initiation sites Micro mechanisms Notched specimens
收录类别	EI
语种	英语
EI入藏号	20124815728108
EI主题词	Cracks
来源库	Compendex
分类代码	543.2 Manganese and Alloys - 545.3 Steel - 933.1.2 Crystal Growth - 951 Materials Science
文献类型	会议论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/117146
专题	材料科学与工程学院_特聘教授组
作者单位	State Key Laboratory of New Nonferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, China
第一作者单位	兰州理工大学
推荐引用方式 GB/T 7714	Wang, G.Z.,Wang, Y.L.,Chen, J.H.. Effects of loading rate on the local cleavage fracture stress σf in notched specimens[C]:International Congress on Fracture,2005:3678-3683.