Influences of grain size and precracking load on the critical stress intensity factor of mild steel

1987 ◽  
Vol 22 (2) ◽  
pp. 612-616
Author(s):  
Ji-Liang Doong ◽  
Jiun-Ren Hwang ◽  
Hsing-Shih Chen
Keyword(s):  
Stress Intensity Factor ◽  
Grain Size ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Mild Steel ◽  
Critical Stress ◽  
Critical Stress Intensity Factor

Effect of Grain Size on the Fracture Toughness of Bimodal Nanocrystalline Materials

2014 ◽  
Vol 936 ◽  
pp. 400-408 ◽  
Author(s):  
Ying Guang Liu ◽  
Xiao Dong Mi ◽  
Song Feng Tian
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Grain Size ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cohesive Zone ◽  
Critical Stress ◽  
Crack Tip ◽  
Critical Stress Intensity Factor ◽  
Coarse Grain

To research the effect of grain size on the fracture toughness of bimodal nanocrystalline (BNC) materials which are composed of nanocrystalline (NC) matrix and coarse grains, we have developed a theoretical model to study the critical stress intensity factor (which characterizes toughness) of BNC materials by considering a typical case where crack lies at the interface of two neighboring NC grains and the crack tip intersect at the grain boundary of the coarse grain, the cohesive zone size is assumed to be equal to the grain sizedof the NC matrix. Blunting and propagating processes of the crack is controlled by a combined effect of dislocation and cohesive zone. Edge dislocations emit from the cohesive crack tip and make a shielding effect on the crack. It was found that the critical stress intensity factor increases with the increasing of grain sizedof the NC matrix as well as the coarse grain sizeD. Moreover, the fracture toughness is relatively more sensitive to the coarse grain size rather than that of NC matrix.

Fracture of monolayer germanene: A molecular dynamics study

2018 ◽  
Vol 32 (22) ◽  
pp. 1850241 ◽  
Author(s):  
Minh-Quy Le
Keyword(s):  
Molecular Dynamics ◽  
Stress Intensity Factor ◽  
Tensile Strength ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
Axial Strain ◽  
Critical Stress Intensity Factor ◽  
Monolayer Graphene ◽  
Fracture Properties

Molecular dynamics simulations with Tersoff potential were performed to study the fracture properties of monolayer germanene at 300 K. The two-dimensional (2D) Young’s modulus, 2D tensile strength and axial strain at the tensile strength of pristine monolayer germanene are about 36.0 and 37.5 N/m; 5.1 and 4.6 N/m; 21.4 and 15.9%, in the zigzag and armchair directions, respectively. Griffith theory was applied to compute the critical stress intensity factor. Compared to monolayer graphene, the critical stress intensity factor of monolayer germanene is much smaller. Fracture pattern and effects of the initial crack length on the fracture properties are also studied. Results are useful for future design and applications of this 2D material.

Probing the Critical Stress Intensity Factor for Slip Transfer across Grain Boundaries by Subgranular Indentation Alfonso

2000 ◽  
Vol 649 ◽  
Author(s):  
H.W. Ngan ◽  
Y.L. Chiu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Critical Stress ◽  
Critical Stress Intensity Factor ◽  
Square Root ◽  
Slip Transfer ◽  
Macroscopic Deformation

ABSTRACTBy analysing the relevant results in the literature, we have found that, when indentation is made on a subgranular level, the hardness varies roughly inversely with the square root of the distance between the indent and the grain boundary. This effect is analogous to the Hall-Petch effect for macroscopic deformation.

Stress Intensity at the Initiation of Instability by R Curve

2014 ◽  
Vol 592-594 ◽  
pp. 1160-1164 ◽  
Author(s):  
S. Sundaresan ◽  
B. Nageswara Rao
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Critical Stress ◽  
Mouth Opening ◽  
Compact Tension ◽  
Critical Stress Intensity Factor ◽  
Pressure Vessels ◽  
Crack Mouth Opening Displacement ◽  
Opening Displacement

The life expectancy or failure of aerospace pressure vessels is evaluated by the critical stress intensity determined by the crack growth resistance curve of a material. Load versus crack mouth opening displacement data is generated from the Compact Tension specimens made from the weld joints of maraging steel rocket motor segments. The steps involved to generate critical stress intensity factor is explained. A power law is adopted to model the crack extension in terms of stress intensity factor and determine the maximum failure load of weld specimens. Maximum failure loads of CT specimens obtained by test and analysis are presented.

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