Wedge-Splitting Test – Determination of Minimal Starting Notch Length for Various Cement Based Composites Part I: Cohesive Crack Modelling

2010 ◽  
Vol 452-453 ◽  
pp. 77-80 ◽  
Author(s):  
Václav Veselý ◽  
Ladislav Řoutil ◽  
Stanislav Seitl
Keyword(s):  
Fracture Mechanics ◽  
Cohesive Crack ◽  
Crack Model ◽  
Singular Stress ◽  
Initiation Point ◽  
Linear Elastic ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Notch Length ◽  
Wedge Splitting

The geometric proportions of cube-shaped specimens subjected to wedge-splitting tests are numerically studied in the paper. The minimal notch length for specimens made of cement based composites varying in characteristic length of the material (a measure of material brittle-ness/heterogeneity) is verified using finite element method code with an implemented cohesive crack model (ATENA). The problem of assigning the crack initiation point (the notch tip vs. the groove corner in the load-imposing area of the specimen) is solved numerically also using both the theory of linear elastic fracture mechanics and the theory of the fracture mechanics of generalized singular stress concentrators in the second part of the two-part paper. Results ob-tained by the different approaches are compared. The minimal notch length is recommended.

Wedge-Splitting Test – Determination of Minimal Starting Notch Length for Various Cement Based Composites Part II: Crack and Notch Fracture Mechanics Approaches

2010 ◽  
Vol 452-453 ◽  
pp. 81-84 ◽  
Author(s):  
Stanislav Seitl ◽  
Jan Klusák ◽  
Václav Veselý ◽  
Ladislav Řoutil
Keyword(s):  
Fracture Mechanics ◽  
Initial Crack ◽  
Cohesive Crack ◽  
Crack Model ◽  
Singular Stress ◽  
Initiation Point ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Notch Length ◽  
Wedge Splitting

The paper focuses on the geometrical proportions of cube-shaped quasi-brittle specimens subjected to a wedge-splitting test (WST). The minimal/optimal initial crack/notch length for successful performance of WST on these specimens is studied numerically (ANSYS). This second part of the paper treats the problem asymptotically, i.e. from the point of view of a very fine grained silicate composite material with negligible characteristic length which describes the level of the material brittleness (i.e. brittle). The problem of competition of the crack initiation point between the notch tip and the groove corner in the load-imposing area of the specimen is solved using theories of both linear elastic fracture mechanics and fracture mechanics of generalized singular stress concentrators. The numerically obtained crack/notch length is compared to results of numerical simulations using cohesive crack model reported in the first part of the paper. The minimal notch length is recommended.

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.

Experimental Investigation on Relative Crack Length For Fracture Toughness of Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1524-1528 ◽  
Author(s):  
Xue Zhi Wang ◽  
Zong Chao Xu ◽  
Zhong Bi ◽  
Hao Wang
Keyword(s):  
Fracture Toughness ◽  
Experimental Investigation ◽  
Crack Length ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Toughness Test ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Wedge Splitting

The wedge splitting test specimens with three series of different relative crack length were used to study the influences of relative crack length on the fracture toughness of common concrete. The suitable formulation for fracture toughness of concrete with different relative crack length was gotten on comparing between fracture toughness test results and computation results of the model developed from Hu formula.

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.

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