Validation of the Two-Parameter Fracture Criterion using finite-element analyses with the critical CTOA fracture criterion

Newman, J. C.

doi:10.1016/j.engfracmech.2015.01.021

Cited by 9 publications

(18 citation statements)

References 25 publications

(36 reference statements)

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“…The use of the plastic‐hinge stress ( S u ) for “bend” specimens was found to be inappropriate for net‐section stresses less than the yield stress. The accuracy of the TPFC was also verified by Newman and Newman through a critical CTOA fracture simulation using both 2D and 3D FE analyses on M(T) models with different widths and crack‐length‐to‐width ratios. The M(T) models were made from three different materials: a hypothetical 2000‐series, 2024‐T3, and 2219‐T87 aluminium alloys.…”

Section: Introductionmentioning

confidence: 85%

“…Although ZIP3D is very efficient and provides accurate results, ZIP2D analyses are often employed to significantly reduce computational run‐times and data analysis . In addition, the predictions provided by the ZIP2D code using the plane‐strain core concept are comparable with those obtained from ZIP3D …”

Section: Fracture Simulation Concepts and Proceduresmentioning

confidence: 97%

“…Recent research, however, suggests that the TPFC equation applies for S n less than the proportional limit stress ( σ pl ) for the 7075‐T6 aluminium alloy. (The previous FE research studies performed on other aluminium alloys had also shown the separation between linear and non‐linear behaviour of the TPFC at the material proportional limit stress, but the authors mislabelled the figures and did not recognize the difference.) Hence, a modified TPFC using the proportional limit stress is expressed as

K_{F} = K_{Ie} / ([], 1 - m ((), S_{n} / σ_{u})) italicfor S_{n} \leq σ_{pl}

where K F and m are the two fracture parameters.…”

Section: Two‐parameter Fracture Criterionmentioning

confidence: 99%

“…In his original formulation, Newman developed the TPFC equation for net‐section stresses less than the yield stress of the material. Such a formulation works well for the 2219‐T87, 7249‐T76511, and 2024‐T3 aluminium alloys . Recent research, however, suggests that the TPFC equation applies for S n less than the proportional limit stress ( σ pl ) for the 7075‐T6 aluminium alloy.…”

Section: Two‐parameter Fracture Criterionmentioning

confidence: 99%

“…If m = 0, the fracture toughness in Equation becomes equivalent to that for LEFM, and ( K Ie ) represents the response of brittle materials that fracture under plane‐strain conditions . In contrast, if m = 1, Equation represents the response of ductile materials that fracture under plane‐stress conditions . Similar to the material's ultimate tensile strength ( σ u ), the parameters K F and m are dependent on temperature, rate of loading, state of stress, and sheet/plate thickness.…”

Section: Two‐parameter Fracture Criterionmentioning

confidence: 99%

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Evaluation of the two‐parameter fracture criterion for various crack configurations made of 7075‐T6 aluminium alloy using finite‐element fracture simulations

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Lacy

Newman

2019

Fatigue Fract Eng Mat Struct

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For many years, a two‐parameter fracture criterion (TPFC) has been used to correlate and predict failure loads on cracked metallic fracture specimens. The current study was conducted to evaluate the use of the TPFC on a high‐strength aluminium alloy, using elastic‐plastic finite‐element (FE) analyses with the critical crack‐tip‐opening angle (CTOA) fracture criterion. In 1966, Forman generated fracture data on middle‐crack tension, M(T), specimens made of thin‐sheet 7075‐T6 aluminium alloy, which is a quasi‐brittle material. The fracture data included a wide range of specimen half‐widths (w) ranging from 38 to 305 mm. A two‐dimensional FE analysis code (ZIP2D) with a “plane‐strain core” option was used to model the fracture process with a critical CTOA chosen to fit the M(T) test data. Fracture simulations were then conducted on other M(T), single‐edge‐crack tension, SE(T), and bend, SE(B), specimens over a wide range in widths (w = 19‐610 mm). No test data were available on the SE‐type specimens. The results supported the TPFC equation for net‐section stresses less than the material proportional limit. However, some discrepancies in the FE fracture simulations results were observed among the numerical analyses made on the three specimen types. Thus, more research is needed to improve the transferability of the TPFC from the M(T) specimen to both the SE(T) and SE(B) specimens for quasi‐brittle materials.

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Section: Introductionmentioning

confidence: 85%

Section: Fracture Simulation Concepts and Proceduresmentioning

confidence: 97%