Mode I stress intensity factor and T-stress by exponential matrix method

2019 ◽  
Vol 103 ◽  
pp. 102287
Author(s):  
J.-M. Nianga ◽  
F. Mejni ◽  
T. Kanit ◽  
A. Imad ◽  
J. Li
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Matrix Method ◽  
Mode I ◽  
T Stress ◽  
Exponential Matrix

scholarly journals Numerical Investigation on Crack Propagation for a Central Cracked Brazilian Disk Concerning Friction

2021 ◽  
Vol 11 (6) ◽  
pp. 2839
Author(s):  
Jiuzhou Huang ◽  
Xin Pan ◽  
Jianxiong Li ◽  
Shiming Dong ◽  
Wen Hua
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Relative Length ◽  
Mode I ◽  
Brazilian Disk ◽  
Crack Type ◽  
T Stress ◽  
Crack Propagation Angle

This paper concerns the effect of friction on crack propagation for the centrally cracked Brazilian disk under diametric forces by using a modified finite element method. It shows that the mode II stress intensity factor decreases obviously with the increase of friction after the crack is closed, while friction has no influence on the stress intensity factor of mode I and T-stress. Meanwhile, there are some significant influences on the crack propagation due to the change of the friction after the crack is closed with the appropriate loading angle and relative length of the crack. When T-stress is positive, the effect of friction becomes obvious and the crack propagation angle increases with a lager friction coefficient. With increasing the friction, the deviation for the crack propagation trajectory increases and the curvature of path decreases, which may lead to the change of crack type. Additionally, the larger relative crack length can amplify the effect of friction, which is similar to the loading angle.

scholarly journals Rectangular Strain-Rosette Method for Measuring the Mode I Stress-Intensity Factor KI and T-stress

2017 ◽  
Vol 7 (5) ◽  
pp. 1922-1929
Author(s):  
A. Hamdi ◽  
N. Benseddiq ◽  
F. Mejni
Keyword(s):  
Stress Intensity Factor ◽  
Asymptotic Expansion ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Tip ◽  
Mode I ◽  
Finite Element Calculations ◽  
Higher Order Terms ◽  
Strain Rosette ◽  
T Stress

In this paper, a new experimental technique for measuring Stress Intensity Factor (SIF) and T-stress under mode I loading is developed. The expressions of the normal and tangential strains close to the crack tip are given using the first five terms of the generalized Westergaard formulation. In order to accurately determine the SIF and T-stress, the method exploits the optimal positioning of a rectangular strain gage rosette near a crack tip in mode I. Thus, errors due to the higher order terms of the asymptotic expansion are eliminated. Finally, a comparison of the analytical results with a finite element calculations, for different specimen dimensions, is carried out.

Fracture analysis of a semi-elliptical crack in a nozzle–vessel junction under external loads

2011 ◽  
Vol 226 (4) ◽  
pp. 871-886 ◽  
Author(s):  
K Sedighiani ◽  
J Mosayebnejad ◽  
M Mafi
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Intensity Factors ◽  
Elliptical Crack ◽  
External Loading ◽  
Mode I ◽  
Loading Conditions ◽  
Intensity Factors ◽  
T Stress

In many previous investigations, the mode I stress intensity factor has been usedalone to analyse and predict the life of cracked cylindrical components. In this article, three-dimensional elastic finite element method was used to analyse semi-elliptical cracks located in the stress concentration area of a nozzle–vessel junction. Stress intensity factors and T-stresses were calculated for different geometrical configurations of a semi-elliptical crack and nozzle–vessel junction under different external loading conditions. The influence of these various parameters and loading conditions on both the stress intensity factors and T-stress is discussed. Itis shown that, for many cases, the mode II stress intensity factor and T-stress are not negligible compared to the mode I stress intensity factor.

ELASTODYNAMIC STRESS INTENSITY FACTOR FOR A FINITE CRACK IN ELASTIC SOLID UNDER 3D TRANSIENT LOADING OF MODE I

2013 ◽  
Vol 05 (04) ◽  
pp. 1350044
Author(s):  
XIANHONG MENG ◽  
ZHAOYU BAI ◽  
MING LI
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Integral Transform ◽  
Elastic Solid ◽  
Scattered Wave ◽  
Mode I ◽  
Finite Width ◽  
Infinite Length ◽  
Distance Ratio

In this paper, the three-dimensional dynamic problem for an infinite elastic medium weakened by a crack of infinite length and finite width is analyzed, while the crack surfaces are subjected to mode I transient linear tractions. The integral transform approach is applied to reduce the governing differential equations to a pair of coupled singular integral equations, whose solutions can be obtained with the typical iteration method. The analytical solution of the stress intensity factor when the first wave and the first scattered wave reach the investigated crack tip is obtained. Numerical results are presented for different values of the width-to-longitudinal distance ratio z/l. It is found that the stress intensity factor decreases with the arrival of the first scattered longitudinal wave and increases with the arrival of the first scattered Rayleigh wave and tends to be stable. The static value considering both the first scattered wave and the first wave is about 50% greater than that considering only the first wave, and then the effect of the reflected wave is remarkable and deserves further study.

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