Modified Equation To Predict Leak/Rupture Criteria For Axially Through-Wall Notched X80 and X100 Linepipes Having a Higher Charpy Energy

2005 ◽  
Vol 128 (4) ◽  
pp. 572-580 ◽  
Author(s):  
Shinobu Kawaguchi ◽  
Naoto Hagiwara ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Fracture Toughness ◽  
Pipe Material ◽  
Test Results ◽  
Absorbed Energy ◽  
Bending Tests ◽  
Three Point Bending ◽  
Full Scale Tests ◽  
Hoop Stresses ◽  
The Relationship ◽  
Modified Equation

A method of predicting the leak/rupture criteria for API 5L X80 and X100 line pipes was evaluated based on the results of hydrostatic full-scale tests for X60, X65, X80, and X100 line pipes with an axially through-wall (TW) notch. The TW notch test results defined the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The defined leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner, Maxey et al. This comparison revealed that the CVN-based equation was not applicable to the pipes having both a CVN energy greater than 120 or 130 J and flow stress greater than the level of X65. In order to predict the leak/rupture criteria for these line pipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and polished Charpy V-notch specimens after static three-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq, which was defined as follows: (Cv)eq=4.5(Cvs)i. The leak/rupture criteria for the X80 and X100 line pipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.

Modified Equation to Predict Leak/Rupture Criteria for Axially Through-Wall Notched X80 and X100 Linepipes Having Higher Charpy Energy

2004 ◽  
Author(s):  
Shinobu Kawaguchi ◽  
Naoto Hagiwara ◽  
Mitsuru Ohata ◽  
Masao Toyoda
Keyword(s):  
Fracture Toughness ◽  
Flow Stress ◽  
Pipe Material ◽  
Test Results ◽  
Absorbed Energy ◽  
Bending Tests ◽  
Full Scale Tests ◽  
Hoop Stresses ◽  
The Relationship ◽  
Modified Equation

A method of predicting the leak/rupture criteria for API 5L X80 and X100 linepipes was evaluated, based on the results of hydrostatic full-scale tests for X60, X65, X80 and X100 linepipes with an axially through-wall (TW) notch. The TW notch test results clarified the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The obtained leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner et al. The comparison revealed that the CVN-based equation was not applicable to the pipes having a CVN energy (Cv) greater than 130 J and flow stress greater than X65. In order to predict the leak/rupture criteria for these linepipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and buffed Charpy V-notch specimens after static 3-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq’ which was defined as follows: (Cv)eq = 4.5 (Cvs)i. The leak/rupture criteria for the X80 and X100 linepipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.

scholarly journals Experimental Study on the Effect of Offset Notch on Fracture Properties of Rock under Three-Point Bending Beam

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Qifeng Guo ◽  
Xinghui Wu ◽  
Meifeng Cai ◽  
Shengjun Miao
Keyword(s):  
Fracture Toughness ◽  
Experimental Study ◽  
Tensile Strength ◽  
Peak Load ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Nominal Strength ◽  
Bending Load ◽  
The Relationship ◽  
Rock Beam

To investigate the effects of offset notch on the fracture properties of rock beam under bending load, granite beam specimens with “one single offset notch” and “central and offset double notches” are made. A series of three-point bending beam tests on the specimens are carried out by controlling the displacement rate of central notch. The whole load-displacement (P-CMOD) curves are obtained. Experimental results show that the larger the distance between the offset notch and beam central is, the larger are the peak load and nominal strength of the specimen. The peak load and nominal strength for the “central and offset double notches” specimens are both larger than those for the “single central notch” specimen. A fracture model considering the effect of offset notch is developed, and the relationship between the offset notch parameter, tensile strength, and fracture toughness is established.

Bending Strength of Al2O3 Ceramics for Textiles Machinery and Elastic Wave Characteristics by Wavelet Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 345-348
Author(s):  
Ki Woo Nam ◽  
B.G. Ahn ◽  
M.K. Kim ◽  
C.S. Son ◽  
Jin Wook Kim ◽  
...  
Keyword(s):  
Elastic Wave ◽  
Bending Strength ◽  
Test Results ◽  
Composite Ceramics ◽  
Bending Tests ◽  
Three Point Bending ◽  
Wave Signal ◽  
Al2o3 Composite ◽  
Signal Characteristics ◽  
Optimized Conditions

The optimized conditions of pressureless sintering were investigated in order to obtain the bending strength and the elastic wave signal of Al2O3 composite ceramics for textiles machinery. As sintering conditions, a temperature range from 1400°C to 1700°C and time from 30 minutes to 150 minutes were applied. Three-point bending tests were conducted on the sintered materials to obtain the strength property. From the test results, the optimum sintering condition was 1600°C, 100 minutes. Al2O3 composite ceramics showed that the elastic wave signal characteristics had a regular correlativity between the optimum sintering temperature and time as well as the maximum bending strength.

Fracture Toughness and Cracking Behaviour of SCC Compared to VC

2013 ◽  
Vol 577-578 ◽  
pp. 205-208
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter
Keyword(s):  
Fracture Toughness ◽  
Fracture Process ◽  
Critical Value ◽  
Fracture Parameter ◽  
Self Compacting Concrete ◽  
Bending Tests ◽  
Three Point Bending ◽  
Notched Specimens ◽  
Subsequent Determination

Vibrated concrete (VC) and self-compacting concrete (SCC) have a substantially different composition, resulting in dissimilar mechanical properties regarding cracking behaviour. The critical value of the mode I stress-intensity factor KICis an appropriate fracture parameter for evaluating fracture toughness and can be obtained from three-point bending tests (3PBT) on small, notched specimens. Subsequent determination of the energy release rate thus allows to examine the crack propagation and fracture process of both concrete types. This paper describes the results of such 3PBTs on samples, made from VC and SCC. Evaluation of the cracking behaviour, derived from these results, reveals remarkable differences.

Fracture properties of self-compacting fiber-reinforced concrete

2020 ◽  
Vol 11 (4) ◽  
pp. 112
Author(s):  
Mariam Farouk Ghazy ◽  
Metwally Abd Allah Abd Elaty ◽  
Omar Daboun
Keyword(s):  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Test Results ◽  
Fiber Reinforced ◽  
Bending Tests ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Slump Flow ◽  
Hardened Properties ◽  
Application Fields

Self-compacting concrete (SCC) is an innovative concrete that does not necessitate vibration for placing and compaction. Nineteen concrete mixes were investigated including a control mix without fibers as well as eighteen SCC with fibers (SCFRC) mixes. Three types of fibers (polypropylene, glass and steel) were used. Slump flow, L-box, V-funnel as well as column segregation tests were conducted to assess the fresh properties. Whereas, compressive, splitting tensile and flexural strengths were measured to assess the hardened properties of SCFRC. Three point bending tests were performed for the purpose of assessing the fracture properties of SCFRC. Test results showed that the inclusion of fibers to produce SCFRC mixtures remarkably enhanced the fracture properties including fracture energy (Gf) and fracture toughness (K1c). Inclusion of steel fibers with 2% volume fractions showed an improvement with 26.9 times for Gf over the control mix. Whereas, 104% increase in K1c was recorded for the same mix over the mix without fibers. Adding fibers to SCC to produce self-compacting fiber reinforced concrete (SCFRC) will expand its advantages. However, the application fields still need to understand the properties of SCFRC.

scholarly journals Study on the Static and Dynamic Fracturing Properties of Marble after Being Damaged Dynamically

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yunqiu Liu ◽  
Anqi Fu ◽  
Binsong Jiang ◽  
Liyuan Yu ◽  
Xiaobing Wang
Keyword(s):  
Fracture Toughness ◽  
Impact Loading ◽  
Split Hopkinson Pressure Bar ◽  
Cumulative Damage ◽  
Bending Tests ◽  
Three Point Bending ◽  
Cyclic Impact Loading ◽  
Loading Tests ◽  
Cyclic Impact ◽  
The Impact

A split Hopkinson pressure bar (SHPB) system was first used to perform the cyclic impact loading tests on notched semicircular bend (NSCB) marble specimens. Then, static and dynamic three-point bending tests were conducted on these dynamically damaged specimens, respectively. In the cyclic impact loading tests, the dynamic elastic modulus decreases gradually as the impact number increases, but dynamic cumulative damage exhibits a growing trend. In the static and dynamic three-point bending tests, when dynamic cumulative damage is less than 0.345, the dynamic fracture toughness values are larger than the static fracture toughness values, but the experimental data exhibit the opposite results when dynamic cumulative damage ranges from 0.345 to 0.369. Through the quantitative analysis of fracture surface morphologies, the roughness and area of the fracture surfaces increase with an increasing dynamic cumulative damage. Under the same dynamic cumulative damage of the specimens, both the roughness and area of the surfaces fractured by static three-point bending are larger than those fractured by dynamic three-point bending.

Experimental Study on Impact Damage in CFRPs

2013 ◽  
Vol 816-817 ◽  
pp. 129-133
Author(s):  
Tai Kun Wang ◽  
Jun Min Du ◽  
Juan Juan Sun
Keyword(s):  
Impact Damage ◽  
Impact Loads ◽  
Bending Tests ◽  
Three Point Bending ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
The Impact ◽  
The Relationship ◽  
Residual Stiffness

With the weight-reduction requirement for transportation tools, more and more carbon fiber reinforced plastics (CFRPs) will be applied. It is known that the plastics will have a brittle fracture under impact loads, and therefore, their resistance capability on impact damage is a crucial factor which restricts the application of CFRPs. The present paper studies the impact damage and residual stiffness of the CFRPs through experiments. The identical specimens were impacted repeatedly by pendulum with a specified constant energy, and then, their residual bending stiffness and strength were measured by three-point-bending tests. Finally, the relationship between the residual stiffness and impact numbers were established. The results will be used in damage-based stiffness predition for CFRPs material and structures.

scholarly journals Processing and mechanical characterization of Al2O3/Ni and Al2O3/C0 composites by pressureless sintering of nanocomposite powders

2018 ◽  
Vol 12 (2) ◽  
pp. 123-128 ◽  
Author(s):  
Yildiz Kafkaslioğlu ◽  
Hüseyin Yilmaz ◽  
Yahya Tür
Keyword(s):  
Fracture Toughness ◽  
Metallic Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Bending Tests ◽  
Three Point Bending ◽  
Green Strength ◽  
Nanocomposite Powders ◽  
Hardness Values

Al2O3/Ni and Al2O3/Co nanopowder mixtures (with 3 vol.% of metallic phase) were synthesized by heterogeneous precipitation method. In order to increase the green strength, polypropylene carbonate (PPC) was used as a binder while preparing green compacts. Uniaxially pressed powder mixtures were sintered at 1550?C for 2 h in a reducing atmosphere. The effects of Ni and Co nanophases on the microstructure and mechanical properties of Al2O3 ceramics were studied by X-ray diffraction, scanning electron microscopy, Vickers indentation technique and three-point bending tests. The metallic phase hindered the densification of alumina matrix, yet hardness values of Al2O3, Al2O3/Ni, and Al2O3/Co composites were comparable. Vickers fracture toughness results indicate that the composites have higher fracture toughness, but the characteristic flexural strength and Weibull modulus are higher for the pure Al2O3.

Temperature and Orientation Dependence of Fracture Behavior of Directionally Solidified Duplex-Phase Crystals Composed of Ni3X-Type Intermetallic Compounds

2006 ◽  
Vol 512 ◽  
pp. 67-72 ◽  
Author(s):  
Koji Hagihara ◽  
Naoyuki Yokotani ◽  
Yukichi Umakoshi
Keyword(s):  
Fracture Toughness ◽  
Temperature Dependence ◽  
Lamellar Structure ◽  
Fracture Behavior ◽  
Orientation Dependence ◽  
Directionally Solidified ◽  
Bending Tests ◽  
Three Point Bending ◽  
Controlling Mechanism ◽  
Fracture Behaviors

Fracture behaviors of three directionally solidified (DS) duplex-phase alloys composed of Ni3Nb(D0a)/Ni3Al(L12), Ni6TaAl(D024)/Ni3Al(L12) and Ni3Ti(D024)/Ni3Si(L12) phases, respectively were investigated by three-point bending tests, focusing on temperature and orientation dependence. The temperature-toughness relation showed dissimilar curves depending on alloy. The increasing rate of fracture toughness was the highest in the Ni3Al/Ni3Nb alloy with fine lamellar structure and was the lowest in the Ni3Al/Ni6TaAl alloy with rod-like precipitates. The controlling mechanism for the temperature dependence of fracture behavior of Ni3Al/Ni3Nb alloys was discussed.

Mechanical Property and Microstructure of the Vitrified-Bonded Ti-Coated CBN Composites

2018 ◽  
Vol 12 (6) ◽  
pp. 862-867
Author(s):  
Xue Sun ◽  
Tianbiao Yu ◽  
Zixuan Wang ◽  
Zhelun Ma ◽  
Maoqiang Xu ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Sintering Temperature ◽  
Cubic Boron Nitride ◽  
Test Results ◽  
Oxidation Reactions ◽  
X Ray Diffraction ◽  
Bending Tests ◽  
Three Point Bending ◽  
Abrasive Surface ◽  
Composite Samples

This paper investigates the mechanical property and microstructures of vitrified-bonded Ti-coated cubic boron nitride (CBN) composites under different sintering conditions. Three-point bending tests of the sintered vitrified-bonded Ti-coated CBN composite samples were carried out, and the microstructure, phase composition, and energy spectrum of the sintered composite samples were analyzed using SEM and X-ray diffraction. The test results indicate that the mechanical properties of the vitrified-bonded Ti-coated CBN composites improve with the increased temperature, and then show a declining trend. It was found that the titanium layer has a protective effect on the CBN abrasive. During the course of sintering, as the temperature increases, titanium in the titanium-coated layer is not only present on the CBN abrasive surface but is also diffused into the glass phase. In addition, oxidation reactions occur, which become stronger with the higher sintering temperature. Thus, the sintering temperature of the vitrified-bonded Ti-coated CBN composites should not be too high. It is better to sinter them in a vacuum rather than in air. Ti-coated CBN grains are not suitable for a vitrified bond with low refractoriness.

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