Compact Tension Testing of Asphalt Binders at Low Temperatures

2017 ◽  
Author(s):  
Michelle Edwards
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Low Temperatures ◽  
Compact Tension ◽  
Small Sample ◽  
Test Method ◽  
Asphalt Binders ◽  
Notch Depth ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement

This presentation will document and discuss the development of a compact tension test for the grading of asphalt binders at low temperatures. The geometry was chosen because it provides an easy way to obtain the plane ­strain fracture toughness, fracture energy, and crack tip opening displacement in brittle failure on a small sample. It is believed that the method will allow for a better ranking of binders in regard to their low ­temperature fracture resistance. Compact tension specimens were prepared in different sizes with varying notch depths. Fracture toughness was found to be constant, regardless of the notch depth or specimen width for both straight and modified binders. Fracture energy was found to decrease with notch depth, which is thought to be the result of energy ­absorbing mechanisms away from the crack­tip. Deeper notches or an energy correction is able to account for that issue. Reproducibility of the fracture test was found to be good with a standard deviation of five to ten percent for fracture toughness and fifteen to twenty percent for fracture energy, which is typical for such tests. Given the fact that brittle fracture properties can vary by orders of magnitude for binders of the same Superpave grade, it is concluded that the test method has a high ability to reveal statistically significant differences in toughness.

Experimental Investigation Into the Fracture Toughness of Polyethylene Pipe Material

2004 ◽  
Author(s):  
Ihab Mamdouh Graice ◽  
Maher Y. A. Younan ◽  
Soheir Ahmed Radwan Naga
Keyword(s):  
Fracture Toughness ◽  
Crack Opening ◽  
Experimental Tests ◽  
Compact Tension ◽  
Test Method ◽  
Elastic Behavior ◽  
Plastic Behavior ◽  
Specimen Thickness ◽  
Pipe Material ◽  
Opening Displacement

The mechanical behavior of the recently produced gas pipes material PE100 is investigated and compared to the commonly used material PE80 to determine their relative advantages. The two materials show plastic behavior at room temperature. The fracture toughness of the two materials is experimentally determined using the two common elastic plastic fracture mechanics methods: the ASTM multiple specimen test method for determining the J-R curve of the materials, and the crack opening displacement (COD) method. The investigation of the fracture behavior of the two materials includes the effect of the specimen thickness as well as specimen configuration. The experimental tests were carried on the compact tension (CT) specimens and the single edge notch bending (SENB) specimens. At −70°C, the materials show elastic behavior, the ASTM test method for determining fracture toughness is applied to SENB specimens to determine KIC of both materials. PE80 shows greater resistance to fracture than PE100.

Novel Specimen Design for Measurement of In-Plane Fracture Toughness of Metals

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Abderrazak Traidia ◽  
Elias Chatzidouros ◽  
Mustapha Jouiad ◽  
Kaamil-Ur-Rahman Shibly
Keyword(s):  
Fracture Toughness ◽  
Pipeline Steel ◽  
Compact Tension ◽  
Experimental Results ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Steel Grades ◽  
Plane Direction ◽  
Crack Tip Opening

Abstract Standard-compliant measurement of the in-plane fracture toughness of metals is often challenging due to insufficient material in the through-thickness direction to extract a full single edge bending (SEB) or compact tension (CT) fracture specimen. In the present work, we propose a new specimen design methodology to overcome this challenge. A W-shaped SEB specimen (called W-SEB) was developed, and its topology was optimized using finite element simulations. The new specimen design was validated numerically and experimentally on a case study showing excellent agreement with standard ASTM E1820 actual SEB specimen geometry. In view assessing the anisotropy of the fracture toughness (KQ and crack tip opening displacement (CTOD)) of pipeline steels susceptible to hydrogen-induced cracking (HIC), the W-SEB specimen was tested on X65 and X42 pipeline steel samples taken from the field. Experimental results show an increase in the maximum CTOD along the in-plane direction as compared to the transverse direction for both steel grades. Such experimental results could lead to important considerations with respect to accurate fitness for service assessment of HIC-damaged assets.

Crack Tip Opening Displacement of X100 SAWL Pipe

2011 ◽  
Vol 299-300 ◽  
pp. 292-297
Author(s):  
Qing Ren Xiong ◽  
Jun Liu ◽  
Jian Xun Zhang ◽  
Yao Rong Feng ◽  
Wen Zhen Zhao
Keyword(s):  
Fracture Toughness ◽  
Base Metal ◽  
Weld Bead ◽  
Test Method ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Crack Propagation Resistance ◽  
Temperature Fracture ◽  
Three Point Bend Test ◽  
Point Bend

The fracture toughness of different zones of X100 SAWL pipe was studied by three-point bend test method under different temperature. At the same temperature, the crack propagation resistance and tear modulus of X100 SAWL pipe distributed as: base metal>HAZ>weld bead, and the distribution of the CTOD value of X100 SAWL pipe is :base metal >weld bead >HAZ. Further investigation was conducted to analyze the decrease of fracture toughness (especially low temperature fracture toughness) and the occurrence of local unstable phenomenon in HAZ specimens.

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