Study on Stress and Strain Field of Mode II Quasi-Static Growing Crack in Pressure-Sensitive Dilatant Material

2009 ◽  
Vol 417-418 ◽  
pp. 665-668
Author(s):  
Yong Yang ◽  
Ning Li ◽  
Li Qiang Tang
Keyword(s):  
Poisson Ratio ◽  
Crack Tip ◽  
Asymptotic Solutions ◽  
Mode Ii ◽  
Stress And Strain ◽  
Viscous Effect ◽  
Crack Tip Field ◽  
Pressure Sensitive ◽  
Stress Mode ◽  
Growing Crack

A mechanical model of the pressure-sensitive dilatant material is established in order to investigate the viscous effect in quasi-static growing crack-tip field. The constitutive equations on the pressure-sensitive dilatant material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as . The asymptotic solutions of separative variable in the crack-tip field of plane stress mode II quasi-static are aslo obtained. According to numerical calculation, the curves of stress, strain and displacement in terms of various parameters are given. The asymptotic solutions of quasi-static growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in the pressure-sensitive dilatant material.

Study on Mode I Quasi-Static Growing Crack Field in the Pressure-Sensitive Dilatant Material

2010 ◽  
Vol 452-453 ◽  
pp. 205-208
Author(s):  
Yong Yang ◽  
Guo Hui Wu ◽  
Li Qiang Tang ◽  
Ning Li
Keyword(s):  
Mechanical Model ◽  
Poisson Ratio ◽  
Crack Tip ◽  
Asymptotic Solutions ◽  
Mode I ◽  
Viscous Effect ◽  
Crack Tip Field ◽  
Pressure Sensitive ◽  
Stress Mode ◽  
Growing Crack

A mechanical model of the pressure-sensitive dilatant material is established in order to investigate the viscous effect in mode I quasi-static growing crack-tip field. The constitutive equations on the pressure-sensitive dilatant material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as . The asymptotic solutions of separative variable in the crack-tip field of plane stress mode I quasi-static are aslo obtained. According to numerical calculation, the curves of stress, strain and displacement in terms of various parameters are given. The asymptotic solutions of quasi-static growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in the pressure-sensitive dilatant material.

Study on Quasi-Static Growing Crack Field in Visco-Elastic Compressible Material

2011 ◽  
Vol 488-489 ◽  
pp. 694-697
Author(s):  
Yong Yang ◽  
Guo Hui Wu ◽  
Li Qiang Tang
Keyword(s):  
Poisson Ratio ◽  
Crack Tip ◽  
Asymptotic Solutions ◽  
Stress Fields ◽  
Mode I ◽  
Mode Ii ◽  
Compressible Material ◽  
Displacement Fields ◽  
Crack Tip Field ◽  
Growing Crack

A mechanical model of the visco-elastic compressible material is established in order to investigate the viscous effect in quasi-static growing crack-tip field. The constitutive equations on the visco-elastic compressible material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as r-1/(n-1). The asymptotic solutions of separative variable in the crack-tip field are aslo obtained. According to numerical calculation, the curves of stress, stain and displacement are given. The results indicate that the near-tip fields are mainly governed by the creep exponent ; the stress fields of mode I and mode II is slightly affected by the elastic compressible deformation; the strain and displacement fields of mode I are deeply affected by the elastic compressible deformation. However, the strain and displacement fields of mode II are less affected by the elastic compressible deformation. The asymptotic solutions of dynamic growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in compressible material.

Dynamic Growing Crack Tip Field in Visco-Elastic Compressible Material

2008 ◽  
Vol 385-387 ◽  
pp. 101-104
Author(s):  
Yong Yang ◽  
Li Qiang Tang ◽  
Yong Wang ◽  
Chen Feng
Keyword(s):  
Poisson Ratio ◽  
Crack Tip ◽  
Asymptotic Solutions ◽  
Stress Fields ◽  
Mode I ◽  
Mode Ii ◽  
Compressible Material ◽  
Displacement Fields ◽  
Crack Tip Field ◽  
Growing Crack

A mechanical model of the visco-elastic compressible material is established in order to investigate the viscous effect in dynamic growing crack-tip field. The constitutive equations on the visco-elastic compressible material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as 1 ( 1) n r− − . The asymptotic solutions of separative variable in the crack-tip field are aslo obtained. According to numerical calculation, the curves of stress, stain and displacement are given. The results indicate that the near-tip fields are mainly governed by the creep exponent n and Mach number M ; the stress fields of mode I and mode II is slightly affected by the elastic compressible deformation; the strain and displacement fields of mode I are deeply affected by the elastic compressible deformation. However, the strain and displacement fields of mode II are less affected by the elastic compressible deformation. The asymptotic solutions of dynamic growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio 0.5 ν→ , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in compressible material.

Analysis of Crack Tip Field in Materials with Creep Behavior

2012 ◽  
Vol 525-526 ◽  
pp. 297-300
Author(s):  
Qing Hua Meng ◽  
Wen Yan Liang ◽  
Zhen Qing Wang
Keyword(s):  
Effective Stress ◽  
Creep Behavior ◽  
Strain Field ◽  
Crack Tip ◽  
Mode I ◽  
Stress And Strain ◽  
Crack Tip Field ◽  
Asymptotic Equations ◽  
Growing Crack

The stress and strain field near the tip of Mode I growing crack in materials under creep conditions is examined. The case of the effective stress equal to zero is considered. The asymptotic equations for the crack of the crack tip field are derived and solved numerically. It is concluded that the rates of stress and strain posses the rδ-1 singularity near the tip crack, and the stresses remain finite at the crack tip.

Study on the Crack-Tip in the Pressure-Sensitive Dilatant Materials

2006 ◽  
Vol 324-325 ◽  
pp. 21-24 ◽  
Author(s):  
Yong Yang ◽  
Li Qiang Tang ◽  
Yong Dong Li
Keyword(s):  
Mechanical Model ◽  
Material Parameter ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Petroleum Engineering ◽  
Rock Deformation ◽  
Crack Tip Field ◽  
Bulk Strain ◽  
Pressure Sensitive ◽  
Growing Crack

In the petroleum engineering, the nonlinear bulk strain or bulk strain rate must be considered in rock deformation, adopting the viscous-elastic theory, a constitutive equation of the pressure-sensitive dilatant materials was established. The governing eqations were deducted in crack-tip field of quasi-static growing crack in pressure-sensitive dilatant materials. And for the mechanical model of a rigid-viscoelastic material interfacial crack, through numerical calculate, the asymptotic solution of the continuous separate variable formal of stress, strain and displacement. The significance of the material parameter in the crack-tip field is discussed. The study of the paper will provide theoretical references for preventing the glide of the mud rock and reducing the arises of the failure of casings of well.

Effect of Welded Mechanical Heterogeneity on Local Stress and Strain Ahead of Growing Crack Tips in the Piping Welds

2011 ◽  
Author(s):  
Lingyan Zhao ◽  
He Xue ◽  
Wei Tang ◽  
Xiurong Fang
Keyword(s):  
Crack Tip ◽  
Local Stress ◽  
Stress And Strain ◽  
Strain Fields ◽  
Mechanical Heterogeneity ◽  
Constant Loading ◽  
Primary Loop ◽  
Weld Joints ◽  
Growing Crack ◽  
Crack Tips

Primary loop recirculation (PLR) piping weld joints are more susceptible to stress corrosion cracking (SCC). But it is difficult to accurately predict SCC growth rate in PLR piping weld joints because the material and mechanical properties in weld joints are quite complicated. Especially, it is provided that hardening in the weld heat-affected zone (HAZ) might play an important role in promoting SCC growth. Considering welded mechanical heterogeneity, the local stress and plastic strain fields ahead of growing crack tip in 316L PLR piping weld joints are analyzed, the effect of constant stress intensity factor (KI) and constant loading on SCC behaviors of PLR piping weld joints is investigated in this study. The results show that the mechanical fields of SCC tips behave quite differently under constant KI and constant loading because of welded mechanical heterogeneity and advanced crack length, which demonstrate that the effect of constant loading on the stress and strain ahead of the growing crack tip is bigger than that of constant KI.

scholarly journals Oscillatory Singularity Behaviors Near Interface Crack Tip for Mode II of Orthotropic Bimaterial

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Xiaomei Yang ◽  
Weiyang Yang ◽  
Junlin Li ◽  
Xuexia Zhang
Keyword(s):  
Interface Crack ◽  
Linear Independence ◽  
Linear Equations ◽  
Crack Tip ◽  
Analytic Solutions ◽  
Mode Ii ◽  
Crack Tip Field ◽  
Fracture Behaviors ◽  
Stress Functions ◽  
Singularity Exponent

The fracture behaviors near the interface crack tip for mode II of orthotropic bimaterial are discussed. The oscillatory singularity fields are researched. The stress functions are chosen which contain twelve undetermined coefficients and an unknown singularity exponent. Based on the boundary conditions and linear independence, the system of twelve nonhomogeneous linear equations is derived. According to the condition for the system of nonhomogeneous linear equations which has a solution, the singularity exponent is determined. Total coefficients are found by means of successive elimination of the unknowns. The theoretical formulae of stress intensity factors and analytic solutions of stress field near the interface crack tip are obtained. The crack tip field is shown by figures.

Crack-tip field on mode II interface crack of double dissimilar orthotropic composite materials

2009 ◽  
Vol 30 (12) ◽  
pp. 1489-1504 ◽  
Author(s):  
Xue-xia Zhang ◽  
Xiao-chao Cui ◽  
Wei-yang Yang ◽  
Jun-lin Li
Keyword(s):  
Composite Materials ◽  
Interface Crack ◽  
Crack Tip ◽  
Mode Ii ◽  
Crack Tip Field ◽  
Orthotropic Composite

Derivation of Equal Area Criterion and its Application to Crack Tip Plastic Zone Analysis

2011 ◽  
Vol 110-116 ◽  
pp. 2918-2925
Author(s):  
Liang Yun Lan ◽  
Can Ming Li ◽  
De Wen Zhao ◽  
Chun Lin Qiu ◽  
Can Ming Li
Keyword(s):  
Plastic Zone ◽  
Poisson Ratio ◽  
Yield Criterion ◽  
Crack Tip ◽  
Projection Area ◽  
Stress And Strain ◽  
Stress Space ◽  
Equal Area ◽  
Von Mises ◽  
Loading Parameter

A new linear yield criterion, referred to as Equal Area (EA) yield criterion, was derived in Haigh Westergaard stress space based on the projection area of its yielding locus on the π-plane equal to the area of von Mises yielding circle. Under the plane stress and strain conditions the crack tip plastic zone dimensions were calculated based on EA yield criterion and compared with those calculated according to the Tresca and von Mises yield criteria. The results showed that the crack tip plastic zone based on EA yield criterion is similar to that based on von Mises yield criterion, but is much different to that based on Tresca yield criterion. Meanwhile, the influences of Poisson ratio and loading parameter on the crack tip plastic zone were investigated based on EA yield criterion.

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