Modified Analytical Method for Stress Intensity Factor Calculation of Infinite MSD Plate Containing Multiple Holes

2010 ◽  
Vol 118-120 ◽  
pp. 269-273
Author(s):  
Jin Fang Zhao ◽  
Li Yang Xie ◽  
Jian Zhong Liu ◽  
Qun Zhao
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Analytical Method ◽  
Fatigue Cracks ◽  
Infinite Plate ◽  
Superposition Method ◽  
Typical Structure ◽  
Two Circular Holes ◽  
Multiple Holes

Multiple site damage (MSD) is the occurrence of small fatigue cracks at several sites within aging aircraft structures. Focusing on this typical structure, an analytical method for calculating the stress intensity factor (SIF) of an infinite plate containing multiple holes was introduced in this paper. The properties of complex variable functions are used to evaluate the stress function. The approximate superposition method is applied to solve SIF problems on multiple holes. Some numerical examples of radial cracks appearing at the boundary of two circular holes are examined by this method. By comparing the analytical and finite analysis results it was realized that the analytical results are accurate and reliable. This modified analytical method is easier to apply than traditional analytical method and can provide SIF solutions for an infinite plate containing multiple holes.

scholarly journals Stress Intensity Factor of an Edge Interface Crack in a Bonded Semi-Infinite Plate

2010 ◽  
Vol 76 (770) ◽  
pp. 1270-1277 ◽  
Author(s):  
Nao-Aki NODA ◽  
Xin LAN ◽  
Kengo MICHINAKA ◽  
Yu ZHANG ◽  
Kazuhiro ODA
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Interface Crack ◽  
Infinite Plate

An Infinite Plate Weakened by Periodic Cracks

2002 ◽  
Vol 69 (4) ◽  
pp. 552-555 ◽  
Author(s):  
Y. Z. Chen ◽  
K. Y. Lee
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Eigenfunction Expansion ◽  
Infinite Plate ◽  
Elastic Response ◽  
Shear Stresses ◽  
Orthotropic Medium ◽  
T Stress ◽  
Periodic Cracks

An infinite plate weakened by doubly distributing cracks is studied in this paper. Two loading cases, the remote tension and the remote shear stresses, are assumed. Analysis is performed for a cracked cell cut from the infinite plate. It is found that the eigenfunction expansion variational method is efficient to solve the problem. The stress intensity factor, the T-stress, and the elastic response are evaluated. The cracked plate can be equivalent to an orthotropic medium without cracks. The equivalent elastic constants are presented.

A Numerical Procedure for Estimating the Stress Intensity Factor of a Crack in a Finite Plate

1964 ◽  
Vol 86 (4) ◽  
pp. 681-684 ◽  
Author(s):  
A. S. Kobayashi ◽  
R. D. Cherepy ◽  
W. C. Kinsel
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
High Speed ◽  
Linear Equations ◽  
Infinite Plate ◽  
Numerical Procedure ◽  
Complex Stress ◽  
Theory Of Elasticity ◽  
Finite Plate

The advantages of the complex variable method are combined with the numerical procedure of collocation for estimating the stress intensity factors in finite, cracked plates subjected to in-plane loadings. In this approach, the complex stress functions for an infinite plate problem are modified to meet the boundary conditions for a finite plate with identical crack configuration. This procedure produces a system of linear equations which can be programmed readily on high-speed computers. The procedure is used to find the elastic stress intensity factor at the crack tip in a centrally notched plate in uniaxial tension. The resulting values are nearly identical to the stress intensity values determined analytically by the theory of elasticity. This numerical procedure should be useful for designers and analysts working in the fields of fracture mechanics and fail-safe concepts.

Nondestructive detection of fatigue cracks in PM 304 stainless steel by internal friction and elasticity

1993 ◽  
Vol 8 (9) ◽  
pp. 2216-2223 ◽  
Author(s):  
S.M. McGuire ◽  
M.E. Fine ◽  
O. Buck ◽  
J.D. Achenbach
Keyword(s):  
Stress Intensity Factor ◽  
Stainless Steel ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Internal Friction ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Mechanical Vibration ◽  
Fatigue Crack Initiation ◽  
304 Stainless Steel

A resonant frequency mechanical vibration method was used to nondestructively detect fatigue crack initiation in notched 304 stainless steel samples prepared by powder metallurgy. This method allowed the determination of an effective elastic modulus and the direct measurement of internal friction. Changes in the modulus and internal friction were found to correlate well with the presence of 50 μm long fatigue cracks. The length of the through cracks initiated at the notch was measured using surface replicas, which were examined in a scanning electron microscope. Small crack growth rate data were also obtained and plotted versus the stress intensity factor. The crack growth rates were compared with long crack data performed on compact tension samples of this material. The short cracks grew at intensity factors below the long crack threshold stress intensity factor.

scholarly journals ANALYSIS OF CRACKS AT THE TORSION VALLARS CAUSED WITHOUT LOADING

2021 ◽  
Vol 07 (03) ◽  
pp. 72-79
Author(s):  
Tehran Mammadli Tehran Mammadli
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Criterion ◽  
Fatigue Cracks ◽  
Tracked Vehicles ◽  
Element Method

Nowadays, the hull suspension systems that use torsion shafts as elastic suspension elements are fitted to the majority of modern tracked vehicles. The main type of failure in such systems is the fracture of the torsion shafts due to the formation of fatigue cracks, which leads to failure of the suspension assemblies. This work presents an analysis of fracture toughness of torsion shafts of a standard tracked chassis used to develop a family of multipurpose transport vehicles GT-TM, GT-TMS, etc. The analysis is carried out under an operating load level for a crack located on the cylindrical part of the torsion shaft, the plane of which is at an angle to the torsion shaft axis and coincides with the position of the main areas of the stress state. The calculation of fracture toughness is based on Irwin fracture criterion. The calculations of the maximum stress intensity factor along the crack front are performed using the finite element method in the ANSYS software package. The results of the analysis of fracture toughness are presented in the form of dependences of the critical depth of the crack on the ratio of the fracture half-length to its depth. The data obtained can be used to determine the residual life of torsion shafts of the tracked vehicles based on the chassis under consideration. Keywords: suspension system, fracture toughness of torsion shafts, edge crack, stress intensity factor, finite element method, Irwin fracture criterion.

Fatigue Life Prediction of Ship Welded Materials

2005 ◽  
Vol 297-300 ◽  
pp. 743-749
Author(s):  
Min Koo Han ◽  
Mamidala Ramulu
Keyword(s):  
Residual Stress ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Crack Propagation ◽  
Crack Closure ◽  
Fatigue Cracks ◽  
Welding Process ◽  
Weld Toe

Fatigue crack propagation life of weld toe crack through residual stress field was estimated using Elber's crack closure concept. Propagation of weld toe crack is heavily influenced by residual stresses caused by the welding process, so it is essential to take into account the effect of residual stresses on the propagation life of a weld toe crack. Fatigue cracks at transverse and longitudinal weld toe was studied, these two cases represent the typical weld joints in ship structures. Numerical and experimental studies are performed for both cases. Residual stresses near the welding area were estimated through a nonlinear thermo-elasto-plastic finite element method and the residual stress intensity factor with Glinka's weight function method. Effective stress intensity factor was calculated using the Newman-Forman-de Koning-Henriksen equation, which is based on the Dugdale strip yield model in estimating the crack closure level, U, at different stress ratios. Calculated crack propagation life coincided well with experimental results.

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