A simplified extreme method for determining double‐K fracture parameters of concrete using experimental peak load

Qing, Longbang; Nie, Ying; Wang, J; Hu, Yu

doi:10.1111/ffe.12493

Cited by 29 publications

(23 citation statements)

References 19 publications

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“…From the load -crack extension (P-a) relationship [37], it is clear that the load increases with crack extension till the peak load and after that it decreases with the crack extension. It is assumed in the SEPLM [37] that the partial derivative of P with respect to a at P = P u is continuous.…”

Section: B Simplified Extreme Peak Load Methods (Seplm)mentioning

confidence: 99%

“…Also, an improper connection between the gauge and specimens may occur and lead to the measurement error of CMOD c . From the results presented by authors [37], it can be seen that the error in results of K IC ini and K IC un for many specimens is more than ±20% which needs further attention for the validity of simplified extreme peak load method. It has been established from the extensive experimental and numerical studies [20][21][22][23][24][25][26]30] that the values of double -K fracture parameters (K IC ini and K IC un ) determined using experimental method and conventional analytical methods (GaussChebyshev integral method, weight function method) are in excellent agreement.…”

mentioning

confidence: 96%

“…Recently, Qing et al [35] proposed a simplified extreme peak load method for determining these fracture parameters. The peak load method [36] requires at least three specimens with different sizes, or the same size but different initial notch lengths in tests whereas the traditional extreme peak load method [35] and the simplified extreme peak load method (SEPLM) [37] require only a single specimen to be tested for determining the fracture parameters. Further, the traditional extreme peak load method Qing et al [35] requires complicated integration procedure to calculate the critical effective crack length whereas the integration procedure is avoided in the simplified extreme peak load method [37].…”

mentioning

confidence: 99%

“…The peak load method [36] requires at least three specimens with different sizes, or the same size but different initial notch lengths in tests whereas the traditional extreme peak load method [35] and the simplified extreme peak load method (SEPLM) [37] require only a single specimen to be tested for determining the fracture parameters. Further, the traditional extreme peak load method Qing et al [35] requires complicated integration procedure to calculate the critical effective crack length whereas the integration procedure is avoided in the simplified extreme peak load method [37]. Qing et al [37] determined the double-K fracture parameters for the experimental data [38] using simplified extreme peak load method (SEPLM) and compared the results with those obtained using weight function method (WFM) [26].…”

mentioning

confidence: 99%

“…Further, the traditional extreme peak load method Qing et al [35] requires complicated integration procedure to calculate the critical effective crack length whereas the integration procedure is avoided in the simplified extreme peak load method [37]. Qing et al [37] determined the double-K fracture parameters for the experimental data [38] using simplified extreme peak load method (SEPLM) and compared the results with those obtained using weight function method (WFM) [26]. From the comparison, it has been pointed out that the simplified extreme peak load method yields generally smaller values of K IC ini and K IC un as compared to those obtained using conventional weight function method.…”

mentioning

confidence: 99%

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Numerical evaluation of simplified extreme peak load method for determining the double – K fracture parameters of concrete

Choubey¹,

Kumar²,

M³

2017

IJET

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Abstract-A simplified extreme peak load method for determining the double -K fracture parameters of concrete has been put forth in the recent research. The method was validated based on experimental test results available in the literature wherein, a significant deviation in predicted values of double -K fracture parameters for some specimens can be observed. The researchers attributed this deviation to measuring error in critical crack mouth opening displacement during fracture test which needs further investigation. Hence a systematic numerical investigation on predicted double -K fracture parameters of concrete using simplified extreme peak load method is presented in this study wherein the peak load and critical crack mouth opening displacement are obtained using fictitious crack model for varying specimen size and initial notch-length to depth ratio. For computation, use of numerical data seems to be precise as experimental data involves error in measuring of critical crack mouth opening displacement during fracture test. Present study reveals that the simplified extreme peak load method is applicable to a limited specimen size range between 200 to 300 mm. This method yields error in the predicted values of double-K fracture parameters of concrete for specimen size below 200mm and beyond 300mm.Keyword-Three-point bending geometry, Mode-I fracture, Concrete, Double-K fracture parameters, Simplified extreme peak load method, Weight function method. I. INTRODUCTIONThe crack propagation study and fracture parameters of concrete structures are described using nonlinear concrete fracture models such as cohesive crack model (CCM) or fictitious crack model (FCM) [1][2][3][4][5][6][7][8][9][10][11][12][13][14] In last two decades, the double-K fracture model has attracted attention of researchers and academia around the world due to many advantages. This model uses LEFM principle in its modified form; it can describe the three important stages of crack propagation in concrete viz.: crack initiation, stable crack propagation and unstable fracture in concrete and the fracture parameters can be determined without use of close loop testing machine. This method is characterized by two material parameters: initial cracking toughness K IC ini and unstable fracture toughness K IC un . The initial cracking toughness is defined as the inherent toughness of the materials, which holds for loading at crack initiation when material behaves elastically and micro cracking is concentrated to a smallscale in the absence of main crack growth. The total toughness at the critical condition is termed as unstable toughness which is regarded as one of the material fracture parameters at the onset of the unstable crack propagation. The initial cracking toughness can be considered as a failure criterion in the design process for design of large size concrete structures like dam, nuclear reactor vessels, and liquid retaining structures wherein crack initiation is taken as one of design criteria. The unstable fracture toughness of the materia...

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Section: B Simplified Extreme Peak Load Methods (Seplm)mentioning

confidence: 99%