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.

Utilization of Williams’ Power Series for Estimation of Crack Behavior under Mixed-Mode Loading

2019 ◽  
Vol 827 ◽  
pp. 203-208
Author(s):  
Lucie Malíková ◽  
Petr Miarka ◽  
Hana Šimonová
Keyword(s):  
Fracture Mechanics ◽  
Mixed Mode ◽  
Crack Tip ◽  
Field Approximation ◽  
Bending Test ◽  
Mixed Mode Loading ◽  
Three Point Bending ◽  
Crack Behavior ◽  
Higher Order Terms ◽  
Specific Fracture

Multi-parameter fracture mechanics concept has been applied to investigate crack behavior under mixed-mode loading, particularly in a semi-circular bending disc. The so-called Williams’ series expansion is used for the crack-tip stress field approximation. It has been shown that application of the generalized fracture mechanics concept can be crucial for materials with specific fracture behavior, such as elastic-plastic or quasi-brittle one, when fracture occurs not only in the very vicinity of the crack tip, but also in a more distant surrounding. Then, considering the higher-order terms of the Williams’ expansion in fracture criteria can be helpful. The attention is devoted to the analysis of the influence of various distances between the supports during the three-point bending test on the results of the further crack propagation direction.

Does the Process Zone Control Crack Growth?

1992 ◽  
Vol 45 (8) ◽  
pp. 367-376 ◽  
Author(s):  
H. Abe´ ◽  
M. Saka ◽  
S. Ohba ◽  
T. Hashida
Keyword(s):  
Crack Growth ◽  
Main Crack ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Tip ◽  
Compact Tension ◽  
Initial Crack ◽  
Zone Control ◽  
Notch Length

Fracture toughness tests were carried out by using small compact tension specimens of Westerly granite. Relation between the load-line displacement and the initial crack-tip separation changed from linear to nonlinear and then to linear again with increasing loading. The onset of the main crack growth was found to occur in a loading level at which the relation was nonlinear. This result disclosed that the onset of main crack growth in granite occurred without experience of the complete area under the tension-softening curve. The critical value of the initial crack-tip separation for onset of the main crack growth was obtained independently of the initial notch length. Also monitoring of the growth of the fracture process zone by ultrasonic technique showed that its length related with the crack-tip separation independently of the initial notch length. By combining the results just mentioned, it was concluded that the fracture process zone controlled the onset of the main crack growth.

scholarly journals Study on the Fracture Process Zone near the Mode I Dynamic Crack Tip

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Chenmeng Ji ◽  
Chengzhi Qi
Keyword(s):  
Approximate Method ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Crack Problem ◽  
Crack Tip ◽  
Complex Stress ◽  
Mode I ◽  
Dynamic Crack ◽  
Stress Function Method

Evaluation of the shape and size of the fracture process zone near the mode I dynamic crack tip is still a problem unsolved completely at present. The research on the relationship between the fracture process zone and crack velocity near the mode I dynamic crack tip is quite limited, and some researchers have also developed experimental methods or numerical methods. In this research, based on the theory of elastodynamics and the complex stress function method, an approximate method for solving the mode I dynamic crack problem was proposed. The fracture process zone near the mode I dynamic crack tip was analyzed. The results showed that the areas of the fracture process zone determined based on the approximate method are nearly the same as the results obtained based on the well-known stress fields. The approximate method could provide a good reference for determining the fracture process zone near the mode I dynamic crack tip since no analytic methods had been found for evaluating the fracture process zone near the dynamic crack tip to the authors’ knowledge.

scholarly journals Determination of some characteristic fracture of concrete of notched beam in bending test

2020 ◽  
Vol 61 (HTCS6) ◽  
pp. 96-101
Author(s):  
Bui Truong Son ◽  
Pham Duc Tho ◽  
Nguyen Thi Nu ◽  
Tran The Truyen ◽  
Tran Nam Hung ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Critical Stress ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Bending Test ◽  
Intensity Factors ◽  
Simulation Results ◽  
Compression Resistance

This paper presents the identification some principal fracture parameters of concretes by experiment and simulation on notched beam in bending. The comparison between experimental and simulation results allows to determinate the Critical stress intensity factors KIC, fracture energy Gf and characteristic lengths of fracture process zone (FPZ) lch of 6 class of concrete with the compression resistance varying from 20 MPa to 50 MPa. These are important parameter in the model for predicting the timelife of concrete structure exposed in coastal area.

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