Combination of Wedge Splitting and Bending Fracture Test-Crack Tip Stress Field and Nonlinear Zone Extent Analysis

2014 ◽  
Vol 969 ◽  
pp. 67-72 ◽  
Author(s):  
Jakub Sobek ◽  
Václav Veselý ◽  
Stanislav Seitl
Keyword(s):  
Numerical Study ◽  
Process Zone ◽  
Crack Tip ◽  
Stress Distributions ◽  
Fracture Test ◽  
Three Point Bending ◽  
Test Geometry ◽  
Configuration Changes ◽  
Bending Fracture ◽  
Wedge Splitting

The paper is focused on a numerical study of fracture test of quasi-brittle materials which is a combination of both the wedge splitting and the three-point bending configuration. Changes in some parameters of the test geometry lead to variations in constraint conditions at the crack tip, which affects the extent of the fracture process zone, i.e. the volume where the crucial processes, determining the possibility and extent of the failure take place. Differences indicated by the failure extents (expressed as the crack pattern) and stress distributions are plotted for several stages of loading for the proposed fracture test configurations.

An Experimental Study on Acoustic Emission Signals during the Three-Point Bending Fracture Test

2014 ◽  
Vol 1000 ◽  
pp. 281-284 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Hana Šimonová ◽  
Tomáš Vymazal ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Fracture Test ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Experimental Tool ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Much has been said in literature about the fracture energy of concrete and its importance. Acoustic emission is an experimental tool well suited for monitoring fracture processes. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviours. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the fracture process in quasi-brittle materials such as concrete and extend them for field applications.

The Effect of Concrete Quality on the Acoustic Emission Parameters during Three-Point Bending Fracture Test

2014 ◽  
Vol 897 ◽  
pp. 149-152 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Tomáš Vymazal ◽  
Iveta Plšková
Keyword(s):  
Acoustic Emission ◽  
Large Scale ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Fracture Test ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture

Acoustic emission is an experimental tool well suited for monitoring fracture processes. The paper presents experiment focused on analysing acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. If we have a better understanding of the relationships between micro structural events and macroscopic behaviour we can better formulate predictive models for large-scale structural performance and reliability. An understanding of microstructureperformance relationships is the key to true understanding of material behaviours. Three-point bending fracture tests were conducted on these specimens and load versus crack mouth opening displacement (Load-CMOD) diagrams were recorded during the testing.

Selecting a Suitable Specimen Shape with Low Constraint Value for Determination of Fracture Parameters of Cementitious Composites

2013 ◽  
Vol 577-578 ◽  
pp. 481-484 ◽  
Author(s):  
Stanislav Seitl ◽  
Sara Korte ◽  
Wouter de Corte ◽  
Veerle Boel ◽  
Jakub Sobek ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Building Materials ◽  
Crack Tip ◽  
Test Configuration ◽  
Three Point Bending ◽  
Finite Element Software ◽  
Splitting Test ◽  
T Stress ◽  
Low Constraint ◽  
Wedge Splitting

The stress intensity factor and the T-stress describing the near-crack-tip fields for selected specimen shapes of a test geometry based on wedge splitting and three point bending tests with several variants of boundary conditions are computed using finite element software ANSYS. The test configuration in question is expected to be a convenient alternative to classical fracture tests (especially the tensile ones) for investigation of the quasi-brittle fracture of building materials, when low constraint is requested. These specimens are investigated within the framework of two-parameter fracture mechanics; near-crack-tip stress field parameters are determined and compared with those of the wedge splitting test due to their shape similarity. The sensitivity of the values of these parameters to the boundary conditions is also shown. Suitable choice of the shape of the specimens is discussed.

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.

Finite Element Analysis of Rubber Particles Size Distribution on Fracture Toughness of Rubber-Modified Polymer

2004 ◽  
Vol 261-263 ◽  
pp. 711-716 ◽  
Author(s):  
Husaini ◽  
Kikuo Kishimoto ◽  
Mitsuo Notomi
Keyword(s):  
Fracture Toughness ◽  
Cell Model ◽  
Numerical Study ◽  
Process Zone ◽  
Outer Region ◽  
Crack Tip ◽  
Small Scale ◽  
Homogeneous Material ◽  
Modified Polymer ◽  
Rubber Particles

A numerical study on the effects of the distribution of rubber particles size on the fracture toughness of rubber-modified polymer alloys was computed. FEM analyses were conducted on the deformation field near the crack tip under mode I for small scale yielding condition. Near the crack tip is modelled as composite of matrix materials and rubber particles. On the other hand, outer region is modelled as homogeneous material whose constitutive equation has been obtained by analysing unit cell model of matrix and rubber particle. Perfect bonding or partial debonding of the interface is assumed in the computation. Matrix and rubber particles are treated as Mises and Mooney-Rivlin materials, respectively. It is shown that energy flux into fracture process zone; Ĵ -integral is smaller for bimodal type than monomodal one. This behavior largely occurred on the partial debonding case. These results imply that the screening effects occurred in the bimodal type larger than monomodal one.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

Statistical analysis of three-point-bending fracture failure of mortar

2021 ◽  
Vol 300 ◽  
pp. 123883
Author(s):  
Peng Zhang ◽  
Peng Yuan ◽  
Junfeng Guan ◽  
Xianhua Yao ◽  
Lielie Li
Keyword(s):  
Statistical Analysis ◽  
Three Point Bending ◽  
Fracture Failure ◽  
Bending Fracture
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