scholarly journals Effects of the surface crack shape on J values along the front of an elliptical crack

2021 ◽  
Author(s):  
Shuai Wang ◽  
Bin Wang ◽  
Yin‐Jin Janin ◽  
Renaud Bourga ◽  
He Xue
Keyword(s):  
Surface Crack ◽  
Elliptical Crack ◽  
Crack Shape

In-Situ Estimation of Surface Crack Shape From Crack Opening Displacement by Use of NCOD Database System

2010 ◽  
Author(s):  
Jingxia Yue ◽  
Zheng He ◽  
Yukio Fujimoto ◽  
Weiguo Wu
Keyword(s):  
Crack Opening Displacement ◽  
Surface Crack ◽  
Fatigue Cracks ◽  
Crack Opening ◽  
Crack Depth ◽  
Database System ◽  
Shape Estimation ◽  
Opening Displacement ◽  
Crack Shape

This paper proposes an in-situ estimation of crack shape from crack opening displacement (COD) by using of a visualized database system consisting of numerical calculation data of normalized crack opening displacement (NCOD) for some kinds of crack types. The relation between crack depth and corresponding NCOD is discussed based on FE analysis results, from which a crack shape estimation principle is deduced. Visualized software named NCOD Database System was developed to facilitate convenient in-situ estimation of crack shape. Shapes of three kinds of surface crack, partial circle crack in plate, fatigue cracks in gusset weld joint and in large-scale member, are successfully estimated by this system. The paper is supported by the Programme of Introducing Talents of Discipline to Universities (B08031).

Probabilistic Critical Fatigue Safety State of the RD2 Type Axle of China Railway Freight Car

2008 ◽  
Vol 44-46 ◽  
pp. 751-758 ◽  
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Ming Fei Feng ◽  
Y. Li ◽  
M.J. Liu ◽  
...  
Keyword(s):  
Crack Growth ◽  
Residual Life ◽  
Shape Change ◽  
Fatigue Cracks ◽  
Crack Size ◽  
Elliptical Crack ◽  
Dynamics Simulation ◽  
Crack Shape ◽  
Railway Freight ◽  
China Railway

Critical fatigue safety state is investigated on RD2 type axle of China railway freight cars. Attention is paid on the grooves near axle boxes, where more fatigue cracks were early appeared even result in at least six derailed accidents. Load history was obtained by vehicle dynamics simulation combining with on-line inspection. Braking loads and effects of maintenance and off-round of wheels are also incorporated. Semi-elliptical and external circumferential cracks are employed for crack growth simulation. Crack shape change and shear stressing of the semi-elliptical crack are taken into account. New crack growth rate modeling in which covers from cracking threshold to toughness related fracture state is applied for residual life evaluation. Critical fatigue safety state is defined as the crack size from which the axle can be safely operated to next overhaul inspection. Critical crack size is estimated step-by-step with the crack shape change. Results show that the external circumferential crack is more dangerous than the semi-elliptical crack. Application more than two years in production verifies that the present assessment is available and reliable.

Surface-Crack Shape Change in Bending Fatigue Using an Inexpensive Resonant Fatiguing Apparatus

1978 ◽  
Vol 6 (3) ◽  
pp. 183 ◽  
Author(s):  
RT Horstman ◽  
KC Lieb ◽  
RL Meltzer ◽  
IC Moore ◽  
WS Pierce ◽  
...  
Keyword(s):  
Surface Crack ◽  
Shape Change ◽  
Bending Fatigue ◽  
Crack Shape

scholarly journals Surface crack shape evolution modelling using an RMS SIF approach

2010 ◽  
Vol 32 (2) ◽  
pp. 297-301 ◽  
Author(s):  
A. Chahardehi ◽  
F.P. Brennan ◽  
S.K. Han
Keyword(s):  
Surface Crack ◽  
Shape Evolution ◽  
Crack Shape

Sensitivity Analysis of Crack Shape on Screening Parameter in JSME FFS Rules for Nuclear Power Plants

2017 ◽  
Author(s):  
Naoki Miura ◽  
Kiminobu Hojo
Keyword(s):  
Sensitivity Analysis ◽  
Fracture Mechanics ◽  
Surface Crack ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Limit Load ◽  
Evaluation Procedure ◽  
Crack Shape ◽  
Screening Parameter

In the 2012 version of the JSME Fitness-for-Service Rules for Nuclear Power Plants, the procedure to calculate screening parameter, SC, which is used for selecting the analysis method (limit load controlled by plastic collapse, elastic-plastic fracture mechanics, or linear elastic fracture mechanics), has been revised to reflect a semi-elliptical surface crack. Both limit load solution and stress intensity factor solution are needed to calculate SC, and the solutions for a semi-elliptical surface crack are different from those for a fan-shape surface crack. In this study, the effect of the difference in crack shape on SC is investigated. Through the results on the sensitivity analysis, the adequacy of the evaluation procedure of SC is ascertained.

Practical Formula of the Shape Evolution of a Surface Crack Under Fatigue Loading

2015 ◽  
Author(s):  
Yosuke Anai ◽  
Toshio Niwa ◽  
Koji Gotoh
Keyword(s):  
Stress Field ◽  
Surface Crack ◽  
Fatigue Cracks ◽  
Stress Gradient ◽  
Estimation Procedure ◽  
Fatigue Loading ◽  
Shape Evolution ◽  
Crack Shape ◽  
Estimation Formula ◽  
Planar Crack

Fatigue life estimation for planar cracks, e.g. part-through surface cracks or embedded cracks is very important because most of fatigue cracks found in welded built-up structures show planar crack morphologies. Although authors had proposed the estimation procedure of crack shape evolution for a planar crack based on the fracture mechanics approach, this method cannot apply if the values of stress intensity factor at the vertices of the surface crack approximated as an ellipse cannot calculated. Then, development of the shape evolution procedure of a planer crack under the stress field with arbitrary gradient, because fatigue cracks in welded built-up structures exist near the stress concentrated region. A Practical estimation formula the shape evolution of a surface crack under stress field with the gradient is proposed in this study. This formula is established by considering the stress field under no crack condition and some former proposed formulae under uniform and pure bending stress fields. The validity of the proposed formula are confirmed by comparing some measured surface crack shape evolutions under some stress gradient conditions.

A Global Limit Load Solution for Plates With Semi-Elliptical Surface Cracks Under Combined Tension and Bending

2004 ◽  
Author(s):  
Yuebao Lei
Keyword(s):  
Finite Element ◽  
Surface Crack ◽  
Crack Depth ◽  
Limit Load ◽  
Elliptical Crack ◽  
Surface Cracks ◽  
Rectangular Crack ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
New Equation

A new global limit load solution is developed in this paper for a precise semi-elliptical surface crack in a plate under combined tension and bending, based on the net-section collapse principle. The new global limit load solution is compared with finite element (FE) results for the semi-elliptical crack, and with the global limit load solution for the circumscribing rectangular crack. The predictions of the new equation are conservative and close to the elastic-perfectly-plastic FE results for shallow cracks. For narrow plates with deep cracks, however, no FE results for the global limit load are available. The differences between the limit load solutions for a semi-elliptical crack and a rectangular crack are negligible for very wide plates but significant for narrow plates, depending on the normalised crack depth and the ratio between the crack length and width of the plate.

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