Influence of Crack Orientation and Crosshead Speed on the Fracture Toughness of PVC Pipe Materials

2004 ◽  
Vol 126 (4) ◽  
pp. 489-496 ◽  
Author(s):  
Tarek M. El-Bagory ◽  
Mohamed S. El-Fadaly ◽  
Maher Y. A. Younan ◽  
Lotfi A. Abdel-Latif
Keyword(s):  
Fracture Toughness ◽  
Experimental Work ◽  
Compact Tension ◽  
Specimen Thickness ◽  
Crosshead Speed ◽  
Operation Conditions ◽  
Pvc Pipe ◽  
Point Bend ◽  
Materials Used ◽  
Pipe Materials

In many modern engineering applications, designers and manufacturers of Polyvinyl chloride (PVC) pipes are interested in the evaluation of fracture toughness under several operation conditions. The aim of the present work is to investigate the fracture toughness of commercial amorphous thermoplastic PVC materials used in piping applications. The experimental work is carried out using three different specimens’ types: Taper Double Cantilever Beam (TDCB), Three Point Bend (TPB), and Compact Tension (CT). Tests are conducted on specimens with thickness (17, 20, 22, and 26 mm), longitudinal and transverse extrusion orientations, at different crosshead speeds (50–500 mm/min) to calculate the fracture toughness of PVC pipe materials. The experimental work has revealed that the crosshead speed has a significant effect on the fracture toughness at low speed rates. This effect, however, becomes insignificant at high rates since, the fracture behavior becomes brittle. The stress intensity factor KQ is approximately the same in both longitudinal and transverse orientations. The fracture toughness decreases as the specimen thickness increases.

Influence of Crack Orientation and Crosshead Speed on the Fracture Toughness of PVC Pipe Materials

2004 ◽  
Author(s):  
T. M. El-Bagory ◽  
M. S. El-Fadaly ◽  
M. Y. A. Younan ◽  
L. A. Abdel-Latif
Keyword(s):  
Fracture Toughness ◽  
Experimental Work ◽  
Engineering Application ◽  
Compact Tension ◽  
Specimen Thickness ◽  
Crosshead Speed ◽  
Operation Conditions ◽  
Pvc Pipe ◽  
Materials Used ◽  
Pipe Materials

In many modern engineering application designers and manufactures of Polyvinyl chloride (PVC) pipes are interested in the evaluation of fracture toughness under several operation conditions. The aim of the present work is to investigate the fracture toughness of commercial amorphous thermoplastic PVC materials used in pipes applications. The experimental work is carried out using three different specimens types: Taper Double Cantilever Beam (TDCB), Three Point Bend (TPB), and Compact Tension (CT). Tests are conducted on specimens with thickness (17,20,22, and 26 mm), longitudinal and transverse extrusion orientations, at different crosshead speeds (50–500 mm/min) to calculate the fracture toughness of PVC pipe materials. The experimental work has revealed that the crosshead speed has a significant effect on the fracture toughness at low speed rates. This effect, however, becomes insignificant at high rates since, the fracture behavior becomes brittle. The stress intensity factor KQ is approximately the same in both longitudinal and transverse orientations. The fracture toughness decreases as the specimen thickness increases.

Validation of Linear Elastic Fracture Mechanics in Predicting the Fracture Toughness of Polyethylene Pipe Materials

2015 ◽  
Author(s):  
Tarek M. A. A. El-Bagory ◽  
Hossam E. M. Sallam ◽  
Maher Y. A. Younan
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Linear Elastic Fracture Mechanics ◽  
Operating Conditions ◽  
Specimen Thickness ◽  
Crosshead Speed ◽  
Linear Elastic ◽  
Piping Systems ◽  
Elastic Fracture ◽  
Point Bend

The main purpose of the present paper is to compare between the fracture toughness based on linear elastic fracture mechanics (GIC), and that based on nonlinear fracture mechanics (JIC). The material of the investigated pipe is a high-density polyethylene (HDPE), which is commonly used in natural gas piping systems. The welds at the pipe junction are produced by butt-fusion (BF), welding. Curved three-point bend (CTPB), fracture specimens are used. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature Ta, equal 23°C. The study reveals that the crosshead speed has a significant effect on the fracture toughness of both welded and unwelded specimens. The results of GIC for different specimen thickness and crosshead speed found previously by the authors [1] have been compared with JIC under the same operating conditions [2]. The comparison between welded and unwelded specimens revealed that in the welded specimens there is a marginal difference between fracture toughness measured using linear elastic fracture mechanics LEFM and elastic plastic fracture mechanics EPFM, for both crosshead speeds.

Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials

2014 ◽  
Author(s):  
Tarek M. A. A. El-Bagory ◽  
Hossam E. M. Sallam ◽  
Maher Y. A. Younan
Keyword(s):  
Fracture Toughness ◽  
Plane Strain ◽  
Specimen Thickness ◽  
Plane Strain Fracture Toughness ◽  
Crosshead Speed ◽  
Apparent Fracture Toughness ◽  
Strain Fracture ◽  
Piping Systems ◽  
Point Bend ◽  
Welding Technique

The main purpose of the present paper is to investigate the effect of strain rate, specimen thickness and welding on the fracture toughness. The material of the investigated pipe is a high-density polyethylene, (HDPE) which is commonly used in natural gas piping systems. The welding technique used in this study is butt fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45mm for both welded and unwelded specimens at room temperature, Ta equal 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane strain fracture toughness, JIc. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.

Evaluation of Fracture Toughness Behavior of Polyethylene Pipe Materials1

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Tarek M. A. A. EL-Bagory ◽  
Hossam E. M. Sallam ◽  
Maher Y. A. Younan
Keyword(s):  
Fracture Toughness ◽  
Plane Strain ◽  
Specimen Thickness ◽  
Plane Strain Fracture Toughness ◽  
Crosshead Speed ◽  
Apparent Fracture Toughness ◽  
Strain Fracture ◽  
Piping Systems ◽  
Point Bend ◽  
Welding Technique

The main purpose of the present paper is to investigate the effect of crosshead speed, specimen thickness, and welding on the fracture toughness. The material of the investigated pipe is a high density polyethylene (HDPE), which is commonly used in natural gas piping systems. The welding technique used in this study is butt-fusion (BF) welding technique. The crosshead speed ranged from 5 to 500 mm/min and specimen thickness ranged from 9 to 45 mm for both welded and unwelded specimens at room temperature, Ta = 20 °C. Curved three point bend (CTPB) specimens were used to determine KQ. Furthermore, the results of fracture toughness, KQ, will be compared with the plane–strain fracture toughness, JIC, for welded and unwelded specimens. The experimental results revealed that KQ increases with increasing the crosshead speed, while KQ decreases as the specimen thickness increases. The investigation reveals that the apparent fracture toughness, KQ, for HDPE pipe of unwelded specimen is greater than that of corresponding value for welded specimen. The same trend was observed for the plane-strain fracture toughness, JIC. At lower crosshead speeds there is a minimum deviation in KQ between welded and unwelded specimens, while the deviation becomes larger with increasing crosshead speed.

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.

Comparison of fracture toughness values of normal and high strength concrete determined by three point bend and modified disk-shaped compact tension specimens

2017 ◽  
Author(s):  
Stanislav Seitl ◽  
José D. Ríos ◽  
Hector Cifuentes
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Strength Concrete ◽  
High Strength ◽  
Compact Tension ◽  
Tension Test ◽  
Test Method ◽  
Strength Concrete ◽  
Compact Tension Test ◽  
Point Bend

The modified disk shaped compact tension test is a configuration derived from standard compact tension test that is used for measuring fracture mechanical properties of primarily metallic materials. The compact tension configuration is commonly used for measurement fracture mechanical properties as e.g. fracture toughness, Young’s modulus, work of fracture etc. The modified compact tension tests imply significant modifications of the specimen morphology in order to avoid premature failure. The modified compact tension test is not proper for quasi-brittle materials due to its complicated shape (steel-concrete interface), but it is easily extracted from drill core and we do not need large amount of material for obtaining fracture properties as we need for e.g. three- or four- point bend test. Since it is a new test method, a wide range of tests is needed to be done before it can be applied. In the paper the selected outputs of the experiments performed on normal and high strength concrete will be processed and the values of fracture mechanical parameters will be discussed.

The use of Indentation Tests to Determine the Fracture Toughness of Brittle Materials

1989 ◽  
Vol 203 (5) ◽  
pp. 333-341 ◽  
Author(s):  
D A Hills ◽  
Y Li
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity ◽  
Experimental Work ◽  
Stress Intensity Factors ◽  
Brittle Materials ◽  
Intensity Factors ◽  
Indentation Tests ◽  
Point Bend

The types of crack that may occur upon indenting highly brittle materials are first reviewed. This leads to a speculation on the source of driving stresses for these various types of crack, and then recent results for the stress intensity factors are presented. Some experimental work, permitting the fracture toughness of glass to be found, is described, which is compared with data obtained from four-point bend specimens.

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