Accession Number : ADA261591


Title :   Approximate Techniques for Predicting Size Effects on Cleavage Fracture Toughness (Jc)


Descriptive Note : Final rept.


Corporate Author : ILLINOIS UNIV AT URBANA DEPT OF COMPUTER SCIENCE


Personal Author(s) : Kirk, Mark T ; Dodds, Jr, Robert H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a261591.pdf


Report Date : Jan 1993


Pagination or Media Count : 40


Abstract : This investigation examines the ability of an elastic T-stress coupled with a modified boundary layer (MBL) solution to predict stresses ahead of a crack tip in a variety of planar geometries. The approximate stresses are used as input to estimate the effective driving force for cleavage fracture (JO) using the micromechanically based approached introduced by Dodds and Anderson. Finite element analyses for a wide variety of planar cracked geometries are conducted which have elastic biaxiality parameters (B) ranging from -0.99 (very low constraint) to +2.96 (very high constraint). The magnitude and sign of B indicate the rate at which crack-tip constraint changes with increasing applied load. All results pertain to a moderately strain hardening material (strain hardening exponent(n) of 10). These analyses suggest that B is an effective indicator of both the accuracy of T-MBL estimates of Jo and of applicability limits on evolving fracture analysis methodologies (i.e. T-MBL, J-Q, and JIJO).. .. Elastic-plastic fracture mechanics, Size effects, Finite element analysis modified boundary layer, T-stress, Jssy, Jo' Q, Structural integrity assessment.


Descriptors :   *FRACTURE(MECHANICS) , *MATHEMATICAL PREDICTION , *MICROMECHANICS , *CLEAVAGE , STRESSES , MATHEMATICAL MODELS , INPUT , LAYERS , PARAMETERS , MATERIALS , FINITE ELEMENT ANALYSIS , BOUNDARIES , INDICATORS , PLASTICS , HARDENING , ESTIMATES , CRACKS , RATES , STRAIN HARDENING , ACCURACY , BOUNDARY LAYER , TOUGHNESS


Subject Categories : Numerical Mathematics
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE