Transferability of elastic-plastic fracture toughness using the Weibull stress approach: significance of parameter calibration

Citation
C. Ruggieri et al., Transferability of elastic-plastic fracture toughness using the Weibull stress approach: significance of parameter calibration, ENG FRACT M, 67(2), 2000, pp. 101-117
Citations number
23
Categorie Soggetti
Mechanical Engineering
Journal title
ENGINEERING FRACTURE MECHANICS
ISSN journal
00137944 → ACNP
Volume
67
Issue
2
Year of publication
2000
Pages
101 - 117
Database
ISI
SICI code
0013-7944(200009)67:2<101:TOEFTU>2.0.ZU;2-5
Abstract
This study focuses on the Weibull stress approach to assess the effects of constraint loss on cleavage fracture toughness (J(c)). The investigation ad dresses the significance of the Weibull modulus m (which bears direct conne ction with parameter calibration schemes) on the correlation of macroscopic fracture toughness for varying crack configurations. In particular, we que stion the ability of current calibration procedures to provide reliable val ues for the Weibull parameters (m, sigma(u)) and present arguments that a n on-uniqueness arises in the calibrated values, i.e., many pairs of (m, sigm a(u)) provide equally good correlation of critical Weibull stress values wi th the distribution of measured fracture toughness values. Our analyses als o show a strong sensitivity of corrected J(c)-values (LSY --> SSY constrain t correction) on parameter m for several specimen geometries and different material flow properties: such results provide compelling support to introd uce an alternative, improved calibration procedure based on a toughness sca ling model. Results of a parameter study suggest typical values of m for a wide range of material flow properties and toughness values. An example ill ustrates application of the toughness scaling model to construct Weibull st ress based, constraint corrections for measured J(c)-values to provide the Weibull modulus, m, for a structural C-Mn steel (BS 4360 Gr 50D). (C) 2000 Elsevier Science Ltd. All rights reserved.