Quasi-Three-Dimensional Stress Fields at an Interface Crack Tip

2009 ◽  
pp. 191-191-15 ◽  
Author(s):  
Z-H Jin ◽  
N Noda
Keyword(s):  
Interface Crack ◽  
Three Dimensional ◽  
Crack Tip ◽  
Stress Fields

Stress Field of Semi-Infinite Interface Crack Tip of Double Dissimilar Orthotropic Composite Materials

2010 ◽  
Vol 97-101 ◽  
pp. 1223-1226
Author(s):  
Jun Lin Li ◽  
Shao Qin Zhang
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Interface Crack ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Stress Fields ◽  
Displacement Fields ◽  
Orthotropic Composite ◽  
Stress Functions ◽  
Secular Equations

The problem of orthotropic composite materials semi-infinite interfacial crack was studied, by constructing new stress functions and employing the method of composite material complex. In the case that the secular equations’ discriminates the and theoretical solutions to the stress fields and the displacement fields near semi-infinite interface crack tip without oscillation and inter-embedding between the interfaces of the crack are obtained, a comparison with finite element example was done to verify the correction of theoretical solution.

scholarly journals The stress field near the tip of a plane stress crack in a gel consisting of chemical and physical cross-links

2019 ◽  
Vol 475 (2227) ◽  
pp. 20180863 ◽  
Author(s):  
Jingyi Guo ◽  
Chung-Yuen Hui ◽  
Mincong Liu ◽  
Alan T. Zehnder
Keyword(s):  
Plane Stress ◽  
Crack Opening ◽  
Three Dimensional ◽  
Crack Tip ◽  
Stress Fields ◽  
Asymptotic Results ◽  
Constant Stretch ◽  
Cross Links ◽  
Theoretical Results ◽  
Gel Network

We study the time-dependent asymptotic stress fields near the tip of a mode I plane stress crack in a hydrogel. The analysis is based on a three-dimensional continuum model which describes the viscoelastic behaviour of a hydrogel gel with permanent and transient cross-links. The viscoelasticity results from the breaking and healing of the transient cross-links in the gel network. We show that the crack tip fields satisfy a local correspondence principle—that is, the spatial singularities of these fields are identical to a hyperelastic cracked body with the same but undamaged networks. Asymptotic results compare very well with finite-element simulations on a single-edge crack specimen loaded under constant stretch rate. We also compare the theoretical results (crack opening profile and crack tip strain field) with experiments and find excellent agreement.

Different Delamination Cracks during Fracture and Their Influences on the Fracture of X70 Pipeline Steel

2008 ◽  
Vol 33-37 ◽  
pp. 91-96
Author(s):  
Zheng Yang ◽  
Hyeon Gyu Beom ◽  
Chang Boo Kim ◽  
Chong Du Cho
Keyword(s):  
Pipeline Steel ◽  
Notch Root ◽  
Three Dimensional ◽  
Stress Triaxiality ◽  
Crack Tip ◽  
Strength Distribution ◽  
Stress Fields ◽  
X70 Pipeline Steel ◽  
Delamination Crack ◽  
Delamination Cracks

Single or multiple of delaminations have been found frequently on the fracture surface of X70 pipeline steel. In this study, the delamination cracks and their influence on the fracture of pipeline are investigated by both experiment and three-dimensional fracture analyses. It is shown that the three-dimensional stress state is prerequisite for delamination crack and the strength distribution of material influences the form and direction of delamination crack. The delamination cracks are produced on the weak interfaces among the material by the tensile stress perpendicular to them before the fracture passes. The direction of delamination crack depends on the three-dimensional stress fields and strength distribution of material near the crack tip or notch root. The delamination cracks of the fracture through thickness of pipe wall make the effective thickness decrease and the delamination cracks of surface crack are perpendicular to the direction of fracture propagation direction. The delamination cracks reduce the stress triaxiality near crack tip and in turn, improve the fracture toughness of X70 pipeline steel.

Three-Dimensional Stress Fields of Elastic Interface Cracks

1991 ◽  
Vol 58 (4) ◽  
pp. 939-946 ◽  
Author(s):  
T. Nakamura
Keyword(s):  
Interface Crack ◽  
Crack Front ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Stress Fields ◽  
Interface Fracture ◽  
Experimental Investigations ◽  
Mode Iii ◽  
Critical Energy Release Rate ◽  
Phase Angles

Various aspects of stress fields near an interface crack in three-dimensional bimaterial plates are investigated. Due to the nature of the resulting deformation field, three-dimensional effects are more critical in a bimaterial plate than in a homogeneous plate. In the close vicinity of the crack front, the stress field is characterized by the asymptotic bimaterial K-field, and its domain size is a very small fraction of a plate thickness. Unlike a homogeneous case, the asymptotic field always consists all three modes of fracture, and an interface crack must propagate under mixed-mode conditions. Furthermore, computational results have shown that the two phase angles representing the relative magnitudes of the three modes strongly depend on the bimaterial properties. It has been also observed that a significant antiplane (Mode III) deformation exists along the crack front, especially near the free surface. Since experimental investigations have shown that critical energy release rate Gc is highly dependent on the phase angles, accurate prediction of the interface fracture behavior requires not only the G distribution but also the variations of phase angles along the crack front.

scholarly journals Application of J2 Integral Method in Calculating Complicated Stress Intensity Factors on Three-dimensional Components

2021 ◽  
Vol 293 ◽  
pp. 02012
Author(s):  
Long. Li ◽  
Yousheng. Deng ◽  
Liqing Meng ◽  
Lingtao Li ◽  
Yunfang Zheng
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Integral Method ◽  
Three Dimensional ◽  
Crack Tip ◽  
Stress Fields ◽  
Experimental Result ◽  
Intensity Factors ◽  
Corner Crack ◽  
Crack Tips

In this paper, a technique to determine complicated stress intensity factors on three-dimensional components, which based on the conservation law and the elementary mechanics is proposed, it only needs the geometric relationship between multiple singular stress fields from the crack section, and obtaind the relationship between the stress at different crack tips. In the expression of the stress intensity factor K, K is proportional to the stress σ at the crack tip, and we can get the supplementary equation of between different stress fields K according to the ratio of the stress at the crack tip, then use the J-integral method to calculate the stress intensity factors of different stress fields. In order to verify the feasibility of this method, a cracked R-fluted shells model was constructed. Under the action of the bending moment, the corner crack propagation is simulated through the reserved corner crack, and two crack tips with different stress fields are generated during the simulation. The experimental result indicates that the proposed method is effective for cracked R-fluted shells. It is also shown that the method has universal applicability for solving complex stress intensity factors on three-dimensional components.

scholarly journals A New Characterization Parameter of out-of-plane Constraint for C(T) Specimens

2018 ◽  
Vol 179 ◽  
pp. 02006
Author(s):  
Zhao Lingyan ◽  
Cui Yinghao ◽  
Yang Fuqiang
Keyword(s):  
Structural Integrity ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Crack Tip ◽  
Stress Fields ◽  
Integrity Assessment ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Material Fracture ◽  
Three Dimensional Finite Element

As the resistance of structures against the crack-tip plastic deformation, constraints has attracted much attention in the research of material fracture behaviour. In order to increase the accuracy of structural integrity assessment, many characterization parameters of in-plane and out-of-plane constraints have been considered and proposed in the last few decades. Three-dimensional finite element analyses have been conducted for five C(T)50 specimens with different out-of-plane constraint. The distributions of four constraint parameters (σ22/σ0, Tz, h and Dp) along crack fronts were calculated. To characterize the out-of-plane constraint, the capability of constraint parameters such as σ22/σ0, Tz, h and Dp were analyzed and compared. Results show that, compared with the three constraint parameters (σ22/σ0, Tz and h) based on crack-tip stress fields, the parameter Dp based on crack-tip equivalent plastic strain is more sensitive to out-of-plane constraint, and may effectively characterize the out-of-plane constraint.

J-INTEGRAL FOR A 3-D INTERFACE CRACK CONFIGURATION IN WELDS OF DISSIMILAR STEELS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4201-4206
Author(s):  
KYONG-HO CHANG ◽  
CHIN-HYUNG LEE
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Interface Crack ◽  
Three Dimensional ◽  
Crack Tip ◽  
J Integral ◽  
Residual Stress Field ◽  
Crack Configuration ◽  
Dissimilar Steels ◽  
Path Independence

In this study, path-independent values of the J-integral in the finite element context for an arbitrary three-dimensional interface crack configuration in welds of dissimilar steels are presented. For the fracture mechanics analysis of an interface crack in welds of dissimilar steels, residual stress analysis and fracture analysis must be performed sequentially. In the analysis of cracked bodies containing residual stress, the usual domain integral formation results in path-dependent values of the J-integral. And unlike cracks in homogeneous materials, an interface crack in welds of dissimilar steels always induces both opening and shearing modes of stress in the vicinity of the crack tip. Therefore, this paper discusses modifications of the conventional J-integral that yield path independence in the presence of residual stress and the total J values which can characterize the severity of an interface crack tip in welds of dissimilar steels. A finite element method which can evaluate the J-integral for an interface crack in three-dimensional residual stress bearing bodies is developed using the modified J-integral definition and total J values. The situation when residual stresses only are present is studied as is the case when mechanical stresses are applied in conjunction with a residual stress field.

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