Elastic-plastic fracture mechanics assessment of low constraint aluminium test specimens

Henry, B.; Luxmoore, A. R.; Sumpter, J. D. G.

doi:10.1007/bf00039572

Cited by 12 publications

(5 citation statements)

References 15 publications

(19 reference statements)

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“…These researchers did not find a significant constraint effect on the fracture initiation toughness J IC , but they observed apparent and replicable changes in the slopes of the J-R curves after certain amount of crack growth. Similar results were reported by Marschall et al [4], Eisele et al [5], Roos et al [6], Henry et al [7] and Haynes and Gangloff [8] for CCP, CT, DECP, SENB and SENT testing with various specimen sizes. All experimental data reported in literature seem to suggest that the J-R curves may depend on the level of constraint.…”

Section: Introductionsupporting

confidence: 79%

“…To validate the experimental results of the ductile crack growth, two-dimensional and three-dimensional finite element analyses (FEA) were performed by many researchers, such as Yuan and Brocks [9], Brocks et al [10], Henry et al [7], Kikuchi [11], and Yan and Mai [12]. Most of these studies used the J 2 flow theory of plasticity for material response idealization, and input the experimental applied load or the load-line displacement to the finite element models of various fracture specimens, including CT, TPB, SENB, SENT and CCP.…”

Section: Introductionmentioning

confidence: 99%

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Determination of Constraint-Modified J-R Curves for Carbon Steel Storage Tanks

Lam

Chao

Zhu

et al. 2003

Journal of Pressure Vessel Technology

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Mechanical testing of A285 carbon steel, a storage tank material, was performed to develop fracture properties based on the constraint theory of fracture mechanics. A series of single edge-notched bend (SENB) specimen designs with various levels of crack tip constraint were used. The variation of crack tip constraint was achieved by changing the ratio of the initial crack length to the specimen depth. The test data show that the J-R curves are specimen-design-dependent, which is known as the constraint effect. A twoparameter fracture methodology is adopted to construct a constraint-modified J-R curve, which is a function of the constraint parameter, A 2 , while J remains the loading parameter. This additional fracture parameter is derived from a closed form solution and can be extracted from the finite element analysis for a specific crack configuration. Using this set of SENB test data, a mathematical expression representing a family of the J-R curves for A285 carbon steel can be developed. It is shown that the predicted J-R curves match well with the SENB data over an extensive amount of crack growth. In addition, this expression is used to predict the J-R curve of a compact tension specimen (CT), and good agreement to the actual test data is achieved. To demonstrate its application in a flaw stability evaluation, a generic A285 storage tank with a postulated axial flaw is used. For a flaw length of 10% of the tank height, the predicted J-R curve is found to be similar to that for a SENB specimen with a short notch, which is in a state of low constraint. This implies that the use of a J-R curve from the ASTM (American Society for Testing and Materials) standard designs, which typically are high constraint specimens, may be overly conservative for analysis of fracture resistance of large structures.

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Section: Introductionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Determination of Constraint-Modified J-R Curves for Carbon Steel Storage Tanks

Lam

Chao

Zhu

et al. 2003

Journal of Pressure Vessel Technology

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“…The J – Q theory and J – A 2 method are the most popular approaches for characterizing the constraint effects under large‐scale yielding conditions 29 . Because of simplification the J – Q theory is applied extensively to the constraint analysis of stationary cracks 4,28,30–33 . Q ‐parameter is defined as the difference between the stresses in the near‐tip region determined by a numerical analysis and the HRR or the small‐scale yielding stress field. where r and θ are the polar coordinates situated at the crack tip, σ 0 is the yield stress, J is the J ‐integral, σ θθ is the hoop stress in the finite‐width geometry and (σ θθ ) SSY is the reference stress under small‐scale yielding (SSY) conditions.…”

Section: Quantification Of Stress Triaxialitymentioning

confidence: 99%

On the transfer of specimen J–R curve to piping components with throughwall circumferential flaw

Pavankumar¹,

Chattopadhyay²,

Dutta³

et al. 2005

Fatigue Fract Eng Mat Struct

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A B S T R A C T Transferability of the specimen J-R/J-T curve to the component level is an importantissue in the field of fracture mechanics. Towards this goal, fracture experiments have been carried out on single-edge bend (SE(B)) and compact tension (CT) specimens and throughwall circumferentially cracked straight pipes/elbows of 200 mm nominal bore (NB) diameter. The pipe material is SA 333 Gr 6 steel (low strength and high toughness material) and specimens are machined from the pipes. Subsequently, elastic-plastic finiteelement analyses have been carried out on these cracked components/specimens in order to evaluate the stress triaxiality levels. It is found that the triaxial levels for these cracked components are similar. Hence, similar fracture behaviour is expected for these components. Consequently, one of the pipe J-R curves is used as a reference J-R curve to consider the crack growth in the analysis and the load deformation behaviour of other pipes/elbows is predicted. The load deformation behaviour of the piping components is also predicted using an extrapolated J-R curve from a specimen that exhibits the similar triaxiality level to that of the cracked components. The predicted results are in good agreement with the experiments.Keywords J-R curve; multiaxiality quotient; stress triaxiality; tearing modulus. N O M E N C L A T U R Ea = crack length a 0 = initial crack length b = ligament length B = thickness of the specimen B N = net thickness of the specimen after side grooving E = Young's modulus of elasticity h = stress triaxiality parameter, see Eq.(2) J = J-integral J iC = initiation toughness (J i ) SZW = initiation toughness obtained using ESIS-P2-92 standard J-R = resistance curve J-T = J-integral-tearing modulus approach n = Ramberg-Osgood power exponent Q = Q-stress T = T-stress W = specimen width for SE(B) and CT specimens α = constant in Ramberg-Osgood constitutive equation η = a function to multiply the area under load versus load point deflection curve to get the J-integral Correspondence:

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“…A year later, Rice and Tracey [18] employed the ratio of the average stresses  m to the effective stresses  eff , calculated according to the Huber-Misses-Hencky (HMH) hypothesis,  m / eff . Some researchers have considered the influence of geometric constraints on the distribution of stresses for three-dimensional cases, analyzing the actual stresses responsible for the crack opening [19], or the differences between the actual description obtained through the FEM analysis and that obtained on the basis of the HRR solution for a case of plane strain [20,21]. It is difficult to discuss all the parameters in one article.…”

Section: Introductionmentioning

confidence: 99%

On The Parameters of Geometric Constraints for Cracked Plates under Tension – Three-Dimensional Problems

Graba

2017

International Journal of Applied Mechanics and Engineering

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This paper provides a comparative analysis of selected parameters of the geometric constraints for cracked plates subjected to tension. The results of three-dimensional numerical calculations were used to assess the distribution of these parameters around the crack front and their changes along the crack front. The study also involved considering the influence of the external load on the averaged values of the parameters of the geometric constraints as well as the relationship between the material constants and the level of the geometric constraints contributing to the actual fracture toughness for certain geometries.

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Elastic-plastic fracture mechanics assessment of low constraint aluminium test specimens

Cited by 12 publications

References 15 publications

Determination of Constraint-Modified J-R Curves for Carbon Steel Storage Tanks

Determination of Constraint-Modified J-R Curves for Carbon Steel Storage Tanks

On the transfer of specimen J–R curve to piping components with throughwall circumferential flaw

On The Parameters of Geometric Constraints for Cracked Plates under Tension – Three-Dimensional Problems

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