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.

Two Parameter Description of Crack Tip Stress Fields for Wedge Splitting Test Specimen: Influence of Wedge Angle

2014 ◽  
Vol 969 ◽  
pp. 345-350
Author(s):  
Stanislav Seitl ◽  
Carlos Bermejo ◽  
Jakub Sobek ◽  
Václav Veselý
Keyword(s):  
Wedge Angle ◽  
Crack Tip ◽  
Stress Fields ◽  
Finite Element Software ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
T Stress ◽  
Two Parameter ◽  
Crack Tip Stress ◽  
Wedge Splitting

Two parameter fracture mechanics uses for description of the crack tip stress fields, not only the stress intensity factor (SIF), but the second term of Williams expansion the T-stress. In the paper, the SIF and T-stress of typical wedge splitting specimens with usual loading arrangements varying in the wedge angle are directly computed using ANSYS finite element software. The influence of the wedge angle value is quantified.

Numerical Stress Analysis of the Biaxial Tension-Compression Wedge-Splitting Test in Vicinity of the Crack Tip

2018 ◽  
Vol 784 ◽  
pp. 85-90
Author(s):  
Stanislav Seitl ◽  
Petr Miarka ◽  
Ildikó Merta ◽  
Zbyněk Keršner
Keyword(s):  
Stress Analysis ◽  
Mechanical Test ◽  
Biaxial Tension ◽  
Crack Tip ◽  
Biaxial Stress ◽  
Stress Fields ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Compression Wedge ◽  
Wedge Splitting

Wedge-splitting test is widely used fracture mechanical test for its stability in measurement during the testing and many papers were published. However, the biaxial wedge-splitting test is relatively a new method and the numerical stress analysis of such test is necessary. Especially the investigation of the stress fields in the vicinity of the crack tip. In this contribution, influence of various biaxial stress level is discussed on values of first and second terms of William’s expansion.

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.

T -STRESS VALUES DURING FRACTURE IN WEDGE SPLITTING TEST GEOMETRIES: A NUMERICAL STUDY

2009 ◽  
pp. 419-428
Author(s):  
Stanislav SEITL ◽  
Pavel HUTAŘ ◽  
Václav VESELÝ ◽  
Zbyněk KERŠNER
Keyword(s):  
Numerical Study ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
T Stress ◽  
Wedge Splitting

Wedge Splitting Test of Foam Concrete Specimens: Calibration Curves

2014 ◽  
Vol 627 ◽  
pp. 281-284 ◽  
Author(s):  
Stanislav Seitl ◽  
Ildikó Merta ◽  
Václav Veselý
Keyword(s):  
Foam Concrete ◽  
Homogeneous Case ◽  
Load Transmission ◽  
Calibration Curves ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
T Stress ◽  
Rectangular Groove ◽  
Concrete Interface ◽  
Wedge Splitting

In the present paper, the well-known wedge splitting test is applied on specimens made from foam concrete. In the case of this material the whole test specimens cannot be made from foam concrete but the rectangular groove, needed for the load transmission pieces, has to be made of stiffer material (typically marble). K-calibration (B1) and T-stress (B2) calibration curves for such specimens are introduced. The objective was to compare and discuss the calibration curves for the homogeneous case, the case with marble parts and the case with marble parts considering the glued marble/foam concrete interface

scholarly journals RILEM Standard: testing methods for determination of the double-K criterion for crack propagation in concrete using wedge-splitting tests and three-point bending beam tests, recommendation of RILEM TC265-TDK

2021 ◽  
Vol 54 (6) ◽  
Author(s):  
Shilang Xu ◽  
Qinghua Li ◽  
Yao Wu ◽  
Lixin Dong ◽  
Yao Lyu ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Unstable Fracture ◽  
Calculation Methods ◽  
Testing Methods ◽  
Three Point Bending ◽  
Standard Testing ◽  
Fracture Parameters ◽  
Splitting Test ◽  
Wedge Splitting

AbstractIn this recommendation, standard testing methods for determination of the double-K criterion for Mode I crack propagation in concrete using wedge-splitting tests and three-point bending beam tests are specified for the fracture parameters of the initial cracking toughness $$K_{Ic}^{ini}$$ K Ic ini and the unstable fracture toughness $$K_{Ic}^{un}$$ K Ic un . Along with the recommendation of the standard testing methods, the theoretical background of the double-K criterion, the calculation methods and the results of round-robin testing for determining the double-K fracture parameters are presented in technical reports [1, 2]. The recommendation of the standard testing methods includes geometry for specimens, fabrication of specimens, testing machine, load transmission system and supports, measuring instruments, determination of initial cracking load Pini, determination of measured maximum load Pmax and initial compliance ci, calculation methods for wedge-splitting test and three-point bending beam test, as well as the testing results and testing report forms. According to these methods, the measured fracture parameters of double-K criterion can be used to describe the onset of cracking, and the onset of unstable cracking or failure for predicting crack initiation, structure failure and crack stability in concrete structures.

An Experimental Investigation on Static and Dynamic Fracture Properties of MgAl

2010 ◽  
Vol 97-101 ◽  
pp. 683-686 ◽  
Author(s):  
Wei Zhou Zhong ◽  
Jing Run Luo ◽  
Shun Cheng Song ◽  
Xi Cheng Huang
Keyword(s):  
Crack Tip ◽  
Value Theory ◽  
Initiation Toughness ◽  
Hopkinson Pressure Bar ◽  
Dynamic Stress Intensity Factors ◽  
Static Compression ◽  
Time Dynamic ◽  
Three Point Bending ◽  
Finite Element Software ◽  
Pressure Bar

Three-point bending specimens of MgAl are loaded by MTS material testing equipment and Hopkinson pressure bar. Strength ratio of MgAl subjected to static compression loading is gained. The dynamic response of three-point bending specimen subjected to impact loading is simulated by ABAQUS finite element software. The stress distribution around crack tip is like shape of butterfly. It indicates that stress decreases quickly away from crack tip. Strain gauges are affixed at the swings of butterfly in the experiments and can experience higher strain signal. So the choice of strain gauge position is reasonable. Based on finite displacement method and the least multiplication value theory, dynamic stress intensity factors at different loading velocities are obtained. According to crack initiation time, dynamic initiation toughness is computed. The results indicate that dynamic initiation toughness of MgAl varies at different loading rates and increases with ball velocity.

Experimental Study of the Influence of the Initial Notch Length in Cubical Concrete Wedge-Splitting Test Specimens

2012 ◽  
Vol 525-526 ◽  
pp. 209-212 ◽  
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter ◽  
Stanislav Seitl
Keyword(s):  
Mouth Opening ◽  
Heterogeneous Material ◽  
Crack Mouth Opening Displacement ◽  
Opening Displacement ◽  
Test Configuration ◽  
Fracture Properties ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Notch Length ◽  
Wedge Splitting

The wedge-splitting test (WST) is a frequently used test configuration for performing stable crack fracture experiments on concrete specimens, thus allowing to determine the fracture process and crack propagation in the heterogeneous material. However, there are no standard rules regarding the wedge-splitting specimens geometry, groove dimensions or notch length. This paper concentrates on the influence of the initial notch length in geometrically identical, cubical specimens, cast from vibrated concrete. The experimental results of nine WSTs under monotonic loading, including Fsp-CMOD curves - splitting force versus crack mouth opening displacement - and fracture energy Gf, are presented. An important effect of the starting notch length on the fracture properties is observed.

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