Characterizations of material constraint effect for creep crack in center weldment under biaxial loading

2021 ◽  
Author(s):  
Yanwei Dai ◽  
Fei Qin ◽  
Yinghua Liu ◽  
Filippo Berto ◽  
Haofeng Chen
Keyword(s):  
Biaxial Loading ◽  
Constraint Effect ◽  
Creep Crack

Enhanced models of creep crack initiation prediction coupled the stress-regime creep properties and constraint effect

2019 ◽  
Vol 74 ◽  
pp. 145-159 ◽  
Author(s):  
Dongquan Wu ◽  
Hongyang Jing ◽  
Lianyong Xu ◽  
Lei Zhao ◽  
Yongdian Han
Keyword(s):  
Crack Initiation ◽  
Constraint Effect ◽  
Stress Regime ◽  
Creep Properties ◽  
Creep Crack

Analytical approaches of creep crack initiation prediction coupled with the residual stress and constraint effect

2018 ◽  
Vol 71 ◽  
pp. 1-15 ◽  
Author(s):  
Dongquan Wu ◽  
Hongyang Jing ◽  
Lianyong Xu ◽  
Lei Zhao ◽  
Yongdian Han
Keyword(s):  
Residual Stress ◽  
Crack Initiation ◽  
Constraint Effect ◽  
Creep Crack ◽  
Analytical Approaches

scholarly journals Estimation of C∗-Integral for Central Cracked Plate Under Biaxial Loading

2020 ◽  
Vol 12 (07) ◽  
pp. 2050079
Author(s):  
Yanwei Dai ◽  
Fei Qin ◽  
Yinghua Liu ◽  
Weizhe Feng ◽  
Guian Qian
Keyword(s):  
Loading Condition ◽  
Biaxial Loading ◽  
Classical Method ◽  
Creep Crack ◽  
Cracked Plate ◽  
Reference Stress ◽  
Creep Time ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

The reference stress method (RSM) is a classical method to estimate [Formula: see text]-integral of creep crack. An extended reference stress method (ERSM) is given for the central cracked plate (CCP) under biaxial loading in this paper. The applicability and verification for the proposed ERSM is given. The study finds that the solutions with the proposed ERSM agree better than those of RSM under biaxial loading condition. A theoretical form to predict the relationship of [Formula: see text]-integral between biaxial loading and uniaxial loading is discussed. Relation between [Formula: see text]-integral and creep time under biaxial loading is validated and discussed.

Mismatch Constraint Effect for Bimaterial Interfacial Creep Crack

2016 ◽  
Vol 853 ◽  
pp. 286-290
Author(s):  
Yan Wei Dai ◽  
Ying Hua Liu ◽  
Hao Feng Chen
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Stress Field ◽  
Structural Integrity ◽  
Creep Crack Growth ◽  
Constraint Effect ◽  
Creep Crack ◽  
Engineering Practices ◽  
Material Mismatch ◽  
Mismatch Effect

Mismatch effect of weldments is important for the assessment of structural integrity at elevated temperature. The interfacial creep crack is a common model which can be found in lots of engineering practices. Recently, the constraint effect is also considered to be significant for the evaluation of creep crack growth under high temperature. In this paper, a model for bimaterial interfacial creep crack is introduced to study the mismatch constraint effect. The stress field for bimaterial interfacial creep crack is investigated. An M*-parameter is proposed to characterize the constraint effect caused by material mismatch for bimaterial creep crack. A comparison is made between the geometry constraint caused by specimen loading and mismatch constraint caused by inhomogeneous material.

Mismatch Constraint Effect of Creep Crack With Modified Boundary Layer Model

2015 ◽  
Vol 83 (3) ◽  
Author(s):  
Yanwei Dai ◽  
Donghuan Liu ◽  
Yinghua Liu
Keyword(s):  
Boundary Layer ◽  
Creep Crack Growth ◽  
Stress Fields ◽  
Constraint Effect ◽  
Creep Crack ◽  
Match Condition ◽  
Maximum Value ◽  
Creep Crack Growth Rate ◽  
Material Mismatch ◽  
Mismatch Effect

Mismatch effect plays a crucial role in weldments, and an independent mismatch constraint parameter M* is proposed to characterize the material mismatch constraint effect in this paper. A mismatched modified boundary layer (MBL) model for creeping solids is developed to simulate the stress field of creep cracks in mismatched weldments. It can be found that there still exists the similarity between creep crack tip stress fields under different mismatch factors. Numerical results show that M* obtains the minimum value on the under match condition and the maximum value on the over match condition. Comparisons between M* and other geometric constraint parameters (A2(t) and Q22) are carried out and the applicability of M* is verified. A modified assessment formula for creep crack growth rate ratio is proposed based on the parameter M*. It is found that M* is a reasonable and remarkable parameter to characterize the mismatch constraint effect of creeping cracks.

Quantifying the Constraint of Three-Dimensional Biaxially Loaded Specimens Containing Semi-Elliptical Cracks Using the J-A2 Method

2012 ◽  
Author(s):  
L. W. Sharpe ◽  
Y. J. Chao
Keyword(s):  
Fracture Toughness ◽  
Structural Integrity ◽  
Biaxial Loading ◽  
Three Dimensional ◽  
Flat Plates ◽  
Constraint Effect ◽  
Element Analysis ◽  
Applied Loading ◽  
Analysis Models ◽  
Elliptical Cracks

Fracture toughness is an important material property used to assess the structural integrity of mechanical components containing cracks. Often, the fracture toughness depends upon the geometry of the component as well as the applied loading. This dependence is referred to as the constraint effect in fracture. The two parameter J-A2 method can be used to quantify the constraint effect. The J-A2 method is a more accurate representation of the stress fields near the crack compared to the classical HRR solution, as additional terms from the series solution are used. The subject of the current study is to apply the J-A2 method to published fracture toughness data of three-dimensional, flat plates containing semi-elliptical cracks and subjected to both uniaxial and biaxial loading to determine the constraint effect and also to determine if the method can be used to predict fracture. The J-A2 results of the flat plates are compared to those of 3PB specimens to determine if loss of constraint exists. Finite element analysis models were developed for each specimen to determine the constraint parameter A2 for each applied loading. The results of the current study reveal that both the uniaxial and biaxial loaded plates exhibit loss of constraint relative to the 3PB specimen and biaxial load increases the constraint of the uniaxially loaded specimen. Further, the J-A2 method shows potential as a tool to predict failure with different constraint level.

scholarly journals Influences of T-Stress on Constraint Effect in Mismatched Modified Boundary Layer Model for Creep Crack

2016 ◽  
Author(s):  
Yanwei Dai ◽  
Yinghua Liu ◽  
Haofeng Chen
Keyword(s):  
Boundary Layer ◽  
Growth Rate ◽  
High Temperature ◽  
Stress Field ◽  
Homogeneous Material ◽  
Layer Model ◽  
Constraint Effect ◽  
Creep Crack ◽  
T Stress ◽  
Creep Time

Constraint effect plays an important role in assessing the stress field and the growth rate of creep crack in components under high temperature. The mismatched modified boundary layer (MMBL) model is extended to creep crack in this paper. For the MMBL model, the Q-parameters for different mismatch factors are studied under different T-stresses. The variation of the dimensionless T-stress in creep zone is given. The variations of open stresses with creep time for different mismatch factors are presented under different T-stresses. The comparisons of Q-parameter between homogeneous material and mismatched materials are made. The influences of mismatch factor on the constraint parameter are discussed. The influence of creep exponent on the open stress is also discussed.

Two-parameter characterization of constraint effect induced by specimen size on creep crack growth

2015 ◽  
Vol 143 ◽  
pp. 121-137 ◽  
Author(s):  
Lei Zhao ◽  
Lianyong Xu ◽  
Yongdian Han ◽  
Hongyang Jing
Keyword(s):  
Crack Growth ◽  
Creep Crack Growth ◽  
Specimen Size ◽  
Constraint Effect ◽  
Creep Crack ◽  
Two Parameter
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