Fracture process zone of notched three-point-bending concrete beams

1999 ◽  
Vol 29 (12) ◽  
pp. 1887-1892 ◽  
Author(s):  
D. Zhang ◽  
K. Wu
Keyword(s):  
Fracture Process ◽  
Fracture Process Zone ◽  
Concrete Beams ◽  
Process Zone ◽  
Three Point Bending

Size effect analysis of quasi-brittle fracture with localizing gradient damage model

2021 ◽  
pp. 105678952098387
Author(s):  
Yi Zhang ◽  
Amit S. Shedbale ◽  
Yixiang Gan ◽  
Juhyuk Moon ◽  
Leong H. Poh
Keyword(s):  
Brittle Fracture ◽  
Size Effect ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Concrete Beams ◽  
Process Zone ◽  
Damage Zone ◽  
Damage Model ◽  
Lattice Models ◽  
Gradient Enhancement

The size effect of a quasi-brittle fracture is associated with the size of fracture process zone relative to the structural characteristic length. In numerical simulations using damage models, the nonlocal enhancement is commonly adopted to regularize the softening response. However, the conventional nonlocal enhancement, both integral and gradient approaches, induces a spurious spreading of damage zone. Since the evolution of fracture process zone cannot be captured well, the conventional nonlocal enhancement cannot predict the size effect phenomenon accurately. In this paper, the localizing gradient enhancement is adopted to avoid the spurious spreading of damage. Considering the three-point bend test of concrete beams, it is demonstrated that the dissipation profiles obtained with the localizing gradient enhancement compare well with those of reference meso-scale lattice models. With the correct damage evolution process, the localizing gradient enhancement is shown to capture the size effect phenomenon accurately for a series of geometrically similar concrete beams, using only a single set of material parameters.

Estimation of the Zone of Failure Extent in Quasi-Brittle Specimens with Different Crack-Tip Constraint Conditions from Stress Field

2013 ◽  
Vol 592-593 ◽  
pp. 262-265 ◽  
Author(s):  
Václav Veselý ◽  
Jakub Sobek ◽  
Petr Frantík ◽  
Michal Štafa ◽  
Lucie Šestáková ◽  
...  
Keyword(s):  
Stress Field ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Tip ◽  
Bending Test ◽  
Stress Fields ◽  
Three Point Bending ◽  
Higher Order Terms ◽  
Crack Tip Constraint

A multi-parameter fracture mechanics concept based on the Williams power series is applied on novel cracked specimen geometries utilizing combined boundary conditions of the wedge splitting and the three-point bending test. Crack tip stress fields for various configurations (causing different constraint conditions at the crack tip and thus also different fracture process zone extents) are numerically investigated and subsequently analytically reconstructed using developed procedure. An importance of using higher order terms of the Williams series is demonstrated.

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