scholarly journals Toughness Calculation of Postfire Normal Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Qingyang Chen ◽  
Anjing Tang ◽  
Zhoudao Lu
Keyword(s):  
Fracture Toughness ◽  
Critical Load ◽  
Crack Opening Displacement ◽  
Analytical Method ◽  
Crack Opening ◽  
Fracture Model ◽  
Opening Displacement ◽  
Normal Concrete ◽  
Critical Fracture ◽  
Fracture Tests

Fracture tests of postfire normal concrete with ten temperatures up to 600°C are implemented. Residual fracture toughness using analytical method is determined. Two situations are divided at critical load when calculating the cohesive fracture toughness. The initial and critical fracture toughness could be calculated from the complete load-crack opening displacement curves. Finally, the validation of double-Kfracture model to the postfire concrete specimens is proved.

Fracture Tests Of Polysilicon Film

1997 ◽  
Vol 505 ◽  
Author(s):  
W. N. Sharpe ◽  
B. Yuan ◽  
R. L. Edwards
Keyword(s):  
Thin Films ◽  
Fracture Toughness ◽  
Crack Opening Displacement ◽  
Crack Opening ◽  
Tensile Loading ◽  
Opening Displacement ◽  
Polysilicon Film ◽  
Fracture Tests

ABSTRACTA new test approach is presented to measure the fracture toughness of thin films. The polysilicon specimen is a center-cracked panel that is 3.5 μm thick and 3 mm wide with a 100 μm long slot in the center. It is subjected to tensile loading, and the crack-opening displacement is measured by interferometry. The average toughness is 1.4 ± 0.65 MPa-m1/2.

Evaluation of Wedge Splitting Fracture Tests Using the Double-K Model: Analysis of the Effect of Hemp Fibre Dosage and Length in Concrete Specimens

2016 ◽  
Vol 249 ◽  
pp. 142-146
Author(s):  
Hana Šimonová ◽  
Ivana Havlíková ◽  
Jakub Sobek ◽  
Alaa Abdulrahman ◽  
Zbyněk Keršner ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Crack Opening Displacement ◽  
Crack Opening ◽  
Opening Displacement ◽  
Critical Crack ◽  
Hemp Fibre ◽  
Fracture Tests ◽  
Critical Crack Opening ◽  
Wedge Splitting

This paper deals with the results obtained from the employment of a selected fracture model to evaluate wedge splitting fracture tests carried out on hemp fibre concrete specimens. The research work was focused mainly on the effect of the dosage and length of hemp fibres on the initiation part of crack propagation in concrete specimens, and on critical crack opening displacement. Concrete mixtures with different volumetric dosages (0.5, 1.0 and 2.0 %) and fibre lengths (10, 20 and 40 mm) were prepared, and six identical specimens were cast from each mixture. Specimens were also cast from a reference mixture, which was without fibres. The specimens were provided with an initial notch and tested using the wedge splitting test method. Load versus crack mouth opening displacement diagrams were recorded during testing and (after data filtering and appropriate modifications) subsequently evaluated using the Double-K fracture model. This model allows the evaluation of two material parameters – the initiation fracture toughness, which defines the onset of stable crack propagation, and the unstable fracture toughness, which defines the onset of unstable cracking or failure. Finally, the critical crack opening displacement was determined with the assumption of the bilinear function of softening in tension.

Determination of Residual Fracture Toughness of Post-Fire Concrete

2013 ◽  
Vol 712-715 ◽  
pp. 1062-1066
Author(s):  
Rui Zhang ◽  
Zhou Dao Lu ◽  
Jiang Tao Yu
Keyword(s):  
Fracture Toughness ◽  
Weight Function ◽  
Analytical Method ◽  
Function Method ◽  
Crack Opening ◽  
Fracture Parameter ◽  
Opening Displacement ◽  
Weight Function Method ◽  
Critical Fracture

Determination of double-K fracture parameter using both analytical and weight function method is carried out in present research. In calculating the cohesive fracture toughness, two situations are divided at critical load. Wedge-splitting tests with ten temperatures varying from 20oC to 600oC are implemented. The complete load-crack opening displacement curves are obtained from which the initial and critical fracture toughness could be calculated experimentally. The validation of double-K fracture model to the post-fire concrete specimens is proved. Meanwhile the weight function method agrees well with the analytical method.

Fracture Toughness Determinations of A-302B and Ni-Mo-V Steels With Various Size Specimens

1966 ◽  
Vol 88 (4) ◽  
pp. 783-791 ◽  
Author(s):  
D. F. Mowbray ◽  
A. J. Brothers ◽  
S. Yukawa
Keyword(s):  
Fracture Toughness ◽  
Crack Opening ◽  
Bend Angle ◽  
Opening Displacement ◽  
Fatigue Precrack ◽  
Strain Fracture ◽  
Shear Lip ◽  
Angle Crack ◽  
Fracture Tests ◽  
Increasing Temperature

Fracture tests were conducted on three steels obtained from heavy-section pieces over a range of test temperatures using single-edge notched (SEN) specimens under tensile loading and notched-bar (NB) specimens in bending. The SEN tests were performed on specimens 0.125 and 0.4 in. thick plus a few specimens 0.020 in. thick. In the NB series Charpy-sized specimens (0.4 in. square) were tested at various temperatures with additional tests on smaller and larger specimens up to 6 in. square at selected temperatures. All specimens were provided with a fatigue precrack at the tip of the notch. The tests were conducted to determine the capability of various size specimens for providing valid plane-strain fracture toughness (GIc or KIc) values at various temperatures for these steels. At very low temperatures all specimens gave similar KIc values. With increasing temperature, KIc values obtained from the larger specimens remained relatively constant and then increased rapidly. At higher temperatures within this range, valid KIc values could not be measured with small specimens. Two possible methods of estimating KIc at these temperatures from small specimen data are discussed. One of these involves a correlation between fracture toughness and shear-lip thickness. The second makes use of a relation between bend angle, crack-opening-displacement, and fracture toughness. The test results are analyzed to show that both methods can be very useful.

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