Journal articles: 'Fracture toughness'

1

Kantor, Matvey Matveevich, Konstantin Grigorievich Vorkachev, Vyacheslav Aleksandrovich Bozhenov, and Konstantin Aleksandrovich Solntsev. "The Role of Splitting Phenomenon under Fracture of Low-Carbon Microalloyed X80 Pipeline Steels during Multiple Charpy Impact Tests." Applied Mechanics 3, no. 3 (June 24, 2022): 740–56. http://dx.doi.org/10.3390/applmech3030044.

Full text

Abstract:

The ambiguity of the splitting effect on X80 low-carbon microalloyed pipeline steels’ tendency towards brittle fracture prompted an experimental study of impact toughness scattering based on multiple Charpy impact tests in a temperature range from 20 °C to −100 °C. A fractographic analysis of a large number of fractured samples was carried out. The relationships between impact toughness, deformability and splitting characteristics were studied. A number of common features of three X80 low-carbon microalloyed pipeline steel fractures were revealed. It was experimentally established that the reason for the scattering of the impact toughness values during completely ductile fracture of specimens, as well as during fracture accompanied by the splitting formation, is the local inhomogeneity of plastic properties. The higher the susceptibility to the formation of splits for a particular steel, the lower the impact toughness. Using the electron backscatter diffraction (EBSD) technique, an uneven distribution of local plasticity in the plastic zone of impact-fractured specimens was established. A comparative analysis of specimens with equal impact toughness values at different test temperatures makes it possible to identify the mechanism of negative splitting influence compensation by the increased plasticity of certain specimen.

APA, Harvard, Vancouver, ISO, and other styles

2

Kubošová, Andrea, Miroslav Karlík, Petr Haušild, and J. Prahl. "Fracture Behaviour of Fe₃Al and FeAl Type Iron Aluminides." Materials Science Forum 567-568 (December 2007): 349–52. http://dx.doi.org/10.4028/www.scientific.net/msf.567-568.349.

Full text

Abstract:

Fracture behaviour of two intermetallic alloys based on FeAl and Fe3Al was studied. On the alloys Fe-40Al-1C (at%) and Fe-29.5Al-2.3Cr-0.63Zr-0.2C (at%) (FA06Z), a basic characterization, the fracture toughness tests and fractographic analysis were carried out. Tensile tests and fracture toughness tests were performed at 20, 200, 400 and 600°C. The fracture toughness values range from 26 MPa.m1/2 at 20°C to 42 MPa.m1/2 at 400°C. In addition, Jintegral dependence on a obtained by potential method was measured. The fractographic analysis showed that samples fractured at 20, 200 and 400°C in the tensile or fracture toughness tests exhibit transgranular cleavage fracture, while at 600°C the ductile dimple fracture predominates.

APA, Harvard, Vancouver, ISO, and other styles

3

Nakano, Yoshifumi. "Fracture Toughness of Steels. (II). Fracture Toughness Test Methods." Journal of the Japan Welding Society 61, no. 7 (1992): 544–50. http://dx.doi.org/10.2207/qjjws1943.61.7_544.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

An, Gyubaek, Jeongung Park, Hongkyu Park, and Ilwook Han. "Fracture Toughness Characteristics of High-Manganese Austenitic Steel Plate for Application in a Liquefied Natural Gas Carrier." Metals 11, no. 12 (December 17, 2021): 2047. http://dx.doi.org/10.3390/met11122047.

Full text

Abstract:

High-manganese austenitic steel was developed to improve the fracture toughness and safety of steel under cryogenic temperatures, and its austenite structure was formed by increasing the Mn content. The developed high-manganese austenitic steel was alloyed with austenite-stabilizing elements (e.g., C, Mn, and Ni) to increase cryogenic toughness. It was demonstrated that 30 mm thickness high-manganese austenitic steel, as well as joints welded with this steel, had a sufficiently higher fracture toughness than the required toughness values evaluated under the postulated stress conditions. High-manganese austenitic steel can be applied to large offshore and onshore LNG storage and fuel tanks located in areas experiencing cryogenic conditions. Generally, fracture toughness decreases at lower temperatures; therefore, cryogenic steel requires high fracture toughness to prevent unstable fractures. Brittle fracture initiation and arrest tests were performed using 30 mm thickness high-manganese austenitic steel and SAW joints. The ductile fracture resistance of the weld joints (weld metal, fusion line, fusion line + 2 mm) was investigated using the R-curve because a crack in the weld joint tends to deviate into the weld metal in the case of undermatched joints. The developed high-manganese austenitic steel showed little possibility of brittle fracture and a remarkably unstable ductile fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

5

An, Gyubaek, Jeongung Park, Mituru Ohata, and Fumiyoshi Minami. "Fracture Assessment of Weld Joints of High-Strength Steel in Pre-Strained Condition." Applied Sciences 9, no. 7 (March 28, 2019): 1306. http://dx.doi.org/10.3390/app9071306.

Full text

Abstract:

Unstable fractures tend to occur after ductile crack initiation or propagation. In most collapsed steel structures, a maximum 15% pre-strain was recorded, at the steel structural connections, during the great earthquake of 1995, in Japan. Almost-unstable fractures were observed in the beam-to-column connections, where geometrical discontinuities existed. Structural collapse and unstable failure occurred after large-scale plastic deformations. Ship structures can also suffer from unstable fractures in the welded joints. The fracture resistance of butt-welded joints subjected to tension in the pre-strained condition was estimated by considering the toughness deterioration, due to pre-strain and toughness correction for constraint loss in a tension specimen. The target specimen for this fracture assessment was a double-edged, through-thickness crack panel, with a crack in the weld joint (heat-affected zone (HAZ)). The critical fracture toughness value (crack tip opening displacement (CTOD)) of a large structure with pre-strain, which was applied to the HAZ region, was estimated from a small-scale, pre-stained, three-point bend specimen. Fracture toughness values, evaluated by a CTOD test, were recently mandated for shipbuilding steel plates. The critical fracture toughness value is a very useful parameter to evaluate the safety of huge ship structures.

APA, Harvard, Vancouver, ISO, and other styles

6

Štefan, Jan, Jan Siegl, Jan Adámek, Radim Kopřiva, and Michal Falcník. "Microstructure and Failure Processes of Reactor Pressure Vessel Austenitic Cladding." Metals 11, no. 11 (October 20, 2021): 1676. http://dx.doi.org/10.3390/met11111676.

Full text

Abstract:

This paper is dedicated to an experimental program focused on the evaluation of microstructure and failure mechanisms of WWER 440 type nuclear reactor pressure vessel cladding made from Sv 08Kh19N10G2B stainless steel. Static fracture toughness tests performed on standard precracked single edge bend specimens revealed extreme variations in fracture toughness values, J0.2. Fractured halves of test specimens were subject to detailed fractographic and metallographic analyses in order to identify the causes of this behavior and to determine the relationship between local microstructure, failure mode and fracture toughness. Results indicated that fracture toughness of the cladding was adversely affected by the brittle cracking of sigma particles which caused a considerable decrease in local ductile tearing resistance. Extreme variations in relative amounts of sigma phase, as well as the extreme overall structural heterogeneity of the cladding determined in individual specimens, provided a reasonable explanation for variations in fracture toughness values.

APA, Harvard, Vancouver, ISO, and other styles

7

Tyson, W. R., O. Vosikovsky, B. Faucher, and D. J. Burns. "Brittle Fracture in Heavy Section Welded T-Joints: Correlation Between Stress Intensity at Fracture and Small-Specimen Toughness Tests." Journal of Offshore Mechanics and Arctic Engineering 112, no. 1 (February 1, 1990): 53–57. http://dx.doi.org/10.1115/1.2919835.

Full text

Abstract:

A fracture mechanics analysis has been made of brittle fractures encountered during a program of fatigue tests of welded plate T-joints. Fracture toughnesses are in reasonable agreement with small-sample test results, if the following factors are taken into account: a specimen size effect (with larger samples having lower toughness); existence of a substantial contribution to the stress intensity factor from residual stresses; and shakedown of residual stresses, with shakedown increasing with increasing applied stress.

APA, Harvard, Vancouver, ISO, and other styles

8

Wang, Wenke, Yang Guo, Yuanbo Li, and Zhengning Li. "Fracture Toughness of Different Region Materials from a Dissimilar Metal Welded Joint in Steam Turbine Rotor." Coatings 12, no. 2 (January 29, 2022): 174. http://dx.doi.org/10.3390/coatings12020174.

Full text

Abstract:

This study systematically evaluated the fracture toughness of a CrMoV/NiCrMoV dissimilar metal welded joint (DMWJ) with buttering layer technology in a steam turbine rotor. The fracture resistance curves and parameters of base metals (BM-1 and BM-2), weld metal (WM), buttering layer (BL), and heat-affected zones (HAZ-1 and HAZ-2) in the welded joint were all obtained. The characteristic microstructures, carbides, and fracture surfaces were observed by optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results revealed a different fracture toughness of each region in the DMWJ. The BM-1 showed a brittle fracture mode, mainly related to the directional needle-shaped carbide M3C. However, HAZ-1, BL, WM, HAZ-2, and BM-2 illustrated ductile fracture mode. The tempered microstructure and dispersed carbides increased the toughness of each material. Except for BM-1, the ductile fracture toughnesses of BL and WM were low in DMWJ due to coarse spherical carbide M7C3. The fracture toughness in the middle of HAZs was higher than that of the corresponding BMs owing to the fine tempered martensite and bainite. The fracture toughness along DMWJ appeared uneven. In sum, these findings look promising for the accurate integrity evaluation of DMWJs.

APA, Harvard, Vancouver, ISO, and other styles

9

BAEK, SEUNG, and CHANG-SUNG SEOK. "FRACTURE CHARACTERISTICS OF DLC ON SILICON USING NANO-INDENTATION AND FEA." International Journal of Modern Physics B 20, no. 25n27 (October 30, 2006): 4213–18. http://dx.doi.org/10.1142/s0217979206041112.

Full text

Abstract:

In this study, using the nano and micro-indentation tests and finite element analysis (FEA), we investigated the fracture behaviors of diamond like carbon (DLC) on silicon in indentation state. Diamond like carbon coating of 3μm and 1.5μm thickness were deposited on polished (100) single crystal silicon substrates by radio frequency plasma assisted chemical vapor deposition (RF-PACVD), respectively. Fracture toughness of DLC films was calculated from the measured lengths of the cracks formed by nano and micro-indentation on each sample. We used various equations such as Lawn's and Liang's equation to calculate the fracture toughness. The effective fracture toughnesses of these DLC films were 1.2 ~1.3 MPam 0.5, calculated by Lawn's and Liang's equations. The true fracture toughness of DLC on silicon, excluding the portion of fracture toughness due to a substrate, was determined to be 4.0~5.1 MPam 0.5. DLC films with crack initiation and propagation were analyzed by finite element method.

APA, Harvard, Vancouver, ISO, and other styles

10

Sun, Yong Xing, Yuan Hua Lin, Long He, Tai he Shi, Da Jiang Zhu, Li Ping Chen, and Su Jun Liu. "Dynamic Fracture Toughness Test and Evaluation for S135 Drill Pipe." Advanced Materials Research 194-196 (February 2011): 2035–38. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.2035.

Full text

Abstract:

During oil-drilling, the fractures of drill tool thread and piercement of drill pipe upset transition are very common in drill pipe failure as an object of petroleum and metallurgical researchers home and abroad. The classical fracture mechanics can only resolve the static fracture problem of oil country tubular goods (OCTG), but not resolve drill pipe failure under dynamic load. It is well known that the API 5D just prescribes strength criterion of drill pipe material but fracture toughness of drill pipe material. So, it is important to study dynamic fracture toughness of drill pipe material and present appropriate toughness criterion, which can not only optimize the drill string structural design, but also reduce fracture failure of drill string. On the basis of presenting main test means of dynamic fracture toughness and referring to the Charpy V test, the new impact experiment instrument is developed. Numerical and experimental comparisons show that the repeated dynamic fracture toughness tested by the impact experiment instrument is more accurate than one time impact, which can better show material characteristic and provide a reliable way to distinguish material characteristic, in the meantime, the correlations between dynamic fracture toughness of drill pipe material and failure of drill pipe is obtained.

APA, Harvard, Vancouver, ISO, and other styles

11

Rief, C., and K. Kromp. "Fracture toughness testing." International Journal of High Technology Ceramics 4, no. 2-4 (January 1988): 301–17. http://dx.doi.org/10.1016/0267-3762(88)90054-9.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Kobayashi, A. S., M. Ramulu, M. S. Dadkhah, K. H. Yang, and B. S. J. Kang. "Dynamic fracture toughness." International Journal of Fracture 30, no. 4 (April 1986): 275–85. http://dx.doi.org/10.1007/bf00019707.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Lee, Deok Bo, and Joo Hyung Kim. "Failure Analysis on Rubber-Modified Epoxy Resin under Various Loading Speed Conditions." Key Engineering Materials 297-300 (November 2005): 1907–12. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1907.

Full text

Abstract:

A rubber-modified epoxy resin is widely used as adhesive and matrix materials for fiber composite material. The structural reliability of composite material depends on the fracture toughness of the matrix resin. In this study, the fracture toughness and the damage zone around a crack tip in rubber-modified epoxy resin were investigated. The volume fractures of rubber (CTBN1300×8) in the rubber-modified epoxy resin were 0%, 5% and 15% under several loading speeds. The fracture toughness(KIC) and the fracture energy(GIC) were measured by using 3-point bending specimens. The 4-point bending specimens were also used to observe damage zones at the vicinity of a crack tip in modified resins. The results show that the values of the fracture toughness and the sizes of damage zones at 5% and 15% rubber content decrease with increase in loading speed.

APA, Harvard, Vancouver, ISO, and other styles

14

Bartsch, Marion, Iulian Mircea, Jens Suffner, and Bernd Baufeld. "Interfacial Fracture Toughness Measurement of Thick Ceramic Coatings by Indentation." Key Engineering Materials 290 (July 2005): 183–90. http://dx.doi.org/10.4028/www.scientific.net/kem.290.183.

Full text

Abstract:

The basic requirement for the use of a ceramic coating is sufficient adhesion to its substrate. A measure of the adhesive properties of a coating is the interfacial fracture toughness. The test method applicable for interfacial fracture toughness measurements depends on the mechanical properties of the material system and the geometry of the test piece. In this work, indentation methods have been evaluated for the estimation of the fracture toughness of ceramic thermal barrier coatings on metallic substrates. Coatings of 100 to 300 µm thickness were applied by electron beam – physical vapour deposition. The performed test types were Vickers indentation at the interface of polished cross sections of the coating system and Rockwell indentation with a brale C indenter, penetrating the coating perpendicular to the surface. Both tests generate delamination, in which the delamination crack length corresponds to the interfacial fracture toughness. Fracture surfaces and cross sections of the fractured coatings were investigated by optical and scanning electron microscope. Determined fracture toughness values are discussed with respect to the loading conditions in the test and the fracture process – i.e. interaction between indenter and coating system and the crack propagation path.

APA, Harvard, Vancouver, ISO, and other styles

15

PARUCHURU, SATYA PRASAD, ANUJ JAIN, and XIAODU WANG. "SIZE REQUIREMENTS OF COMPACT SANDWICH SPECIMEN FOR TESTING OF BONE." Journal of Mechanics in Medicine and Biology 07, no. 04 (December 2007): 419–31. http://dx.doi.org/10.1142/s0219519407002406.

Full text

Abstract:

It is well understood that bone quality deteriorates due to aging, disease, etc., and may be affected by factors at different length scales due to its hierarchical microstructure. Fracture toughness is one of the properties that assess bone quality. The compact sandwich (CS) specimen gives a better choice of bone sample size, and therefore suits a wide variety of fracture toughness testing needs and constraints. Reliable and statistically valid overall CS specimen size requirements are established in this paper; these serve as guidelines for choosing the CS specimen size. Finite element analysis (FEA) is used for simulating fracture toughness tests. Experimental fracture toughness tests are carried out to verify the FEA results. The experimental results are verified qualitatively by performing scanning electron microscopy (SEM) on the fractured specimen surfaces.

APA, Harvard, Vancouver, ISO, and other styles

16

Zhao, Yawei, Xinjian Sun, Peng Cao, Yifeng Ling, Zhen Gao, Qibing Zhan, Xinjie Zhou, and Mushuang Diao. "Mechanical Performance and Numerical Simulation of Basalt Fiber Reinforced Concrete (BFRC) Using Double-K Fracture Model and Virtual Crack Closure Technique (VCCT)." Advances in Civil Engineering 2019 (November 11, 2019): 1–15. http://dx.doi.org/10.1155/2019/5630805.

Full text

Abstract:

This paper mainly investigates the fracture parameters of Basalt Fiber Reinforced Concrete (BFRC) with various fiber lengths and dosages using Double-K fracture model. The model was developed by fracture criterion using ABAQUS Virtual Crack Closure Technique (VCCT), and the results of the model and experiments were compared. The basalt fiber with length of 6 mm and 12 mm was added into concrete in the dosage of 0.0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% by volume of concrete, respectively. Concrete specimens were cast into three dimensions, i.e., 60 mm × 180 mm × 480 mm, 80 mm × 240 mm × 640 mm, and 100 mm × 300 mm × 800 mm. Then, three-point bending test was conducted on precast-notched beams. The load versus cracking mouth opening displacement (P-CMOD curve) was developed in order to evaluate cracking and breaking load. The initial fracture toughness and unstable fracture toughness were derived from the Double-K fracture model aimed to optimize the fiber length and dosage. The results showed that the initial fracture toughness and unstable fracture toughness increased first and then decreased with the increase in fiber dosage, and basalt fiber with length of 6 mm and dosage of 0.2% performed the best toughening effect on concrete. The comparison results showed that numerical simulation can better simulate the initiation and propagation of BFRC fractures and achieve the dynamic propagation process of fractures.

APA, Harvard, Vancouver, ISO, and other styles

17

M R, Sunil Kumar, Eva Schmidova, Pavel Konopík, Daniel Melzer, Fatih Bozkurt, and Neelakantha V Londe. "Fracture Toughness Analysis of Automotive-Grade Dual-Phase Steel Using Essential Work of Fracture (EWF) Method." Metals 10, no. 8 (July 29, 2020): 1019. http://dx.doi.org/10.3390/met10081019.

Full text

Abstract:

Fracture toughness determination of dual-phase DP450 steel using the essential work of fracture (EWF) methodology is the major focus of this research work. The EWF method is used for the determination of fracture toughness of thin sheets in a plane stress dominant condition. The EWF method is discussed in detail with the help of DP450 steel experimental results. Double edge notched tension (DENT) specimens with fatigue pre-crack and without fatigue crack (notched) have been used for testing. Specific essential work of fracture (we), crack tip opening displacement (δce) and crack tip opening angle (ψe) parameters were used for the comparative analysis. High-intensity laser beam cutting technology was used for the preparation of notches. Fracture toughness values of fatigue pre-cracked and notched samples were compared. The effect of notch tip radius and fatigue crack on the fracture toughness values were analysed. Digital image correlation (DIC) technology was used for the identification of local strain distribution and validation of the methodology. Fractured surfaces were examined by a scanning electron microscope (SEM) to analyse the fracture morphology and stress state.

APA, Harvard, Vancouver, ISO, and other styles

18

Hu, Hui, Yu Peng Cao, and Pei Ning Li. "Study on Fracture Toughness Prediction of Non Power Law Hardening Material by Using Local Approach." Advanced Materials Research 197-198 (February 2011): 1640–46. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.1640.

Full text

Abstract:

A new method of fracture toughness K1C prediction of non power law hardening material by using cleavage fracture local approach is proposed in this paper. The fracture toughness of A508-Ⅲ 16MnR at different cleavage fracture probability are predicted by using the method. To most of pressure vessel carbon-manganese steels, cleavage fracture is likely to occur at the load corresponding to 62% cleavage fracture probability. Hence, the fracture toughness corresponding to the load is the most possible fracture toughness of the steels. The values of fracture toughness corresponding to 62% cleavage fracture probability is close to that of testing fracture toughness. The work of this paper expends the application of Beremin cleavage fracture model in predicting fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

19

An, Gyubaek, Jeongung Park, Daehee Seong, and Ilook Han. "FRACTURE SAFETY OF LIQUEFIED NATURAL GAS TANK IN CRYOGENIC CONDITIONS." International Journal of Maritime Engineering 165, A1 (July 10, 2023): 115–24. http://dx.doi.org/10.5750/ijme.v165ia1.1208.

Full text

Abstract:

High-manganese austenitic steel has been developed as a new cryogenic steel for application in liquified natural gas (LNG) storage and fuel tanks, with improved fracture toughness and safety at cryogenic temperatures. Generally, the fracture toughness decreases at lower temperatures; therefore, cryogenic steel requires a high fracture toughness to prevent unstable fractures. This study conducted unstable ductile fracture tests with 30-mm-thick high-manganese austenitic steel and evaluated its applicability to LNG storage and fuel tanks. The ductile fracture resistance in the weld joints was evaluated, including the weld metal and heat-affected zone. The unstable fracture resistance was evaluated for different LNG tank types. It was found that high-manganese austenitic steel has excellent unstable fracture characteristics and good material performance as a cryogenic steel; therefore, it can be applied in LNG storage and fuel tanks.

APA, Harvard, Vancouver, ISO, and other styles

20

Qu, Wen Qing, Min Yuan Song, Jun Shan Yao, and Hai Yun Zhao. "Effect of Temperature and Heat Treatment Status on the Ductile Fracture Toughness of 2219 Aluminum Alloy." Materials Science Forum 689 (June 2011): 302–7. http://dx.doi.org/10.4028/www.scientific.net/msf.689.302.

Full text

Abstract:

Through measurement of fracture toughness of 2219 aluminum alloy three-point bend specimen and observation of fracture surface and microstructure at different temperature, the influences of temperature and heat treatment status on the fracture toughness of 2219 aluminum alloy are discussed. The results show that temperature has an important influence on the fracture toughness of 2219 aluminum alloy. Compared with fracture toughness in room temperature, the fracture toughness is increased by 36% at low temperature. Heat treatment status also affects fracture toughness greatly, and fracture toughness in the T62 state is better than that in the T87 state. In conclusion, the reason why enhancement of fracture toughness of 2219 aluminum alloy at low temperature appearance is concluded.

APA, Harvard, Vancouver, ISO, and other styles

21

Gierth, Anne Zora, Simon Syring, Tommy Mielke, and Doru C. Lupascu. "Fracture toughness on compact tension specimen as a quality parameter for cement stone." ce/papers 6, no. 6 (December 2023): 1055–60. http://dx.doi.org/10.1002/cepa.2902.

Full text

Abstract:

AbstractA series of tests of compression strength and fracture toughness of hardened cement paste (cement stone) was carried out. The compression strength was tested on cubes with side lengths of 10, 20, 30 and 40 mm. Fracture toughness was measured on compact tension (CT) specimens with dimensions commonly used in metallurgy; two different thicknesses were used (h x l x b: 50 x 48 x 3 mm3 and 50 x 48 x 8 mm3). A particularly stiff piezo‐controlled test frame was used as testing device. The different thicknesses of the specimens allow the investigation of a possible size effect in toughness. In a Weibull statistical evaluation, the scatter of the strength results is compared with the scatter of the measured toughnesses. It could be shown that the fracture toughness results are as reliable as the strength results and the method is a useful addition to the research on fracture of binders.

APA, Harvard, Vancouver, ISO, and other styles

22

He, Zhi-Bo, Pan Liu, Da-Sheng Wang, and Yue-Bing Li. "Fracture toughness evaluation of 37CrNi3MoVE steel used for high-pressure air storage cylinder." Materials Express 12, no. 1 (January 1, 2022): 123–32. http://dx.doi.org/10.1166/mex.2022.2133.

Full text

Abstract:

The air storage cylinders, forming part of the impulse air system for submarine, are high-pressure steel cylinders dome-shaped at each end. To prevent the risk of cylinders rupture, the fracture toughness of cylinders is necessary to be tested. The three-point bending samples used in the fracture toughness experiment were taken from a cylinder made of 37CrNi3MoVE steel. With the consideration of the effect of the manufacturing process, both axial specimens and circumferential specimens were sampled, and the fracture toughness was compared. The effective data obtained from fracture toughness experiments were processed by different standards, such as ISO 12135 standard and ASTM E1820 standard. The fracture surface is analyzed from macroscopic and microscopic perspectives. From the test results of circumferential fracture toughness and axial fracture toughness, it can be clearly seen that under the influence of the processing technology, the circumferential fracture toughness of the cylinder of the high-pressure gas cylinder is smaller than the circumferential fracture toughness. Finally, comparing the fracture toughness values obtained by the ASTM E1820 standard with the fracture toughness values obtained by the ISO 12135 standard, it is found that the fracture toughness values obtained under the ASTM E1820 standard are all greater than the fracture toughness values obtained by the ISO 12135 standard.

APA, Harvard, Vancouver, ISO, and other styles

23

Nakano, Yoshifumi. "Fracture Toughness of Steels(III). Fracture Toughness and Its Control Factors." Journal of the Japan Welding Society 61, no. 8 (1992): 636–43. http://dx.doi.org/10.2207/qjjws1943.61.8_636.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

OHATA, Mitsuru. "Fracture Toughness ^|^amp; Fracture Performance Evaluation." JOURNAL OF THE JAPAN WELDING SOCIETY 78, no. 5 (2009): 453–55. http://dx.doi.org/10.2207/jjws.78.453.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

TAGAWA, Tetsuya. "Fracture Toughness ^|^amp; Fracture Performance Evaluation." JOURNAL OF THE JAPAN WELDING SOCIETY 80, no. 5 (2011): 470–71. http://dx.doi.org/10.2207/jjws.80.470.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Shamim, Shahrukh, Gaurav Sharma, and Chandrabalan Sasikumar. "The Effect of Intermetallic Phases on Ductile to Brittle Transition of Aluminium-Iron Alloy." Applied Mechanics and Materials 592-594 (July 2014): 770–75. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.770.

Full text

Abstract:

The effect of intermetallic phases and grain size on ductile to brittle transition temperature of Aluminium-Iron alloy (Al–11% Fe) was investigated in this research work. An Izod impact testing method was adopted to study the DBTT in the temperature interval of 77 K to 373 K. The ductile-brittle transition points: fracture transition plastic (FTP), fracture-appearance transition temperature (FATT), impact energy transition temperature (IETT), fractional surface area of cleavage (brittle) and fibrous (ductile) fractures and grain size of the samples were also determined. The fracture toughness of Al-Fe alloy found decreasing with temperature in contrast to conventional materials. The fractographic investigation revealed that the microstructural changes play a major role in determining the fracture toughness of these alloys. Annealing of these samples slightly improved the fracture toughness as the spherical morphology of intermetallic particles resists the crack propagation.

APA, Harvard, Vancouver, ISO, and other styles

27

Fuhrmann, D., D. Murchison, S. Whipple, and K. Vandewalle. "Properties of New Glass-Ionomer Restorative Systems Marketed for Stress-Bearing Areas." Operative Dentistry 45, no. 1 (January 1, 2020): 104–10. http://dx.doi.org/10.2341/18-176-l.

Full text

Abstract:

SUMMARY Objectives: The purpose of this study was to evaluate the properties (fracture toughness, surface hardness) of newer conventional glass-ionomer restorative materials that are marketed for posterior stress-bearing areas compared with more traditional glass-ionomer restorative materials marketed for non–load-bearing areas and composite-resin restorative materials. Methods and Materials: Notched-beam fracture toughness specimens were created in a mold with each tested material (Equia Forte, GC America, with and without a surface coating of Equia Forte Coat; Ketac Universal, 3M/ESPE; ChemFil Rock, Dentsply; Fuji IX GP Extra, GC; Ionostar Molar, VOCO; Filtek Z250, 3M/ESPE; Filtek Supreme Ultra, 3M/ESPE) and fractured using a universal testing machine after 24 hours of storage. Hardness values were determined on the surface of the fracture toughness specimens using a hardness tester. Data were analyzed with a one-way ANOVA and Tukey's post hoc test per property (alpha=0.05). Results: The composite-resin restorative materials had significantly greater fracture toughness than the glass-ionomer materials. There was no significant difference in fracture toughness between the glass-ionomer materials. The use of a resin coating significantly increased the surface hardness of the newer glass ionomer marketed for stress-bearing areas. Conclusions: Fracture toughness was not improved with the newer glass-ionomer restorative materials marketed for stress-bearing areas compared to the conventional glass-ionomer materials, however a resin coating provided greater surface hardness.

APA, Harvard, Vancouver, ISO, and other styles

28

Kieu, Le Hai, Jean Marc Delaye, and Claude Stolz. "Modeling Radiation Effects on the Fracture Process in Simplified Nuclear Glass." Key Engineering Materials 488-489 (September 2011): 154–57. http://dx.doi.org/10.4028/www.scientific.net/kem.488-489.154.

Full text

Abstract:

Experimentally, the evolution of several mechanic properties (hardness, density, Young’s modulus, fracture toughness) is observed in nuclear glasses under irradiation. In this work, classical molecular dynamics calculations are performed to better understand fracture mechanisms in simplified nuclear glasses at atomistic scale and to explain the radiation effects. Fractures are simulated in more disordered glasses, representative of irradiated samples, to reveal radiation effects. We observe a lower elastic limit and a greater plasticity in the irradiated glass that can explain its larger fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

29

Liu, Kaiyuan, Jian Xiong, Xi Zhang, Xiao Fan, and Le Li. "Prediction of Fracture Toughness in the Shale Formation Based on Well Logging and Seismic Data: A Case Study of the Lower Silurian Longmaxi Formation in the Sichuan Basin, China." Geofluids 2020 (November 30, 2020): 1–13. http://dx.doi.org/10.1155/2020/8896352.

Full text

Abstract:

The rock physics experiments and fracture toughness tests of shales from the Lower Silurian Longmaxi Formation in the Sichuan Basin in China were carried out. Based on this, the calculation model of the fracture toughness was constructed, thus, the single well evaluation of the fracture toughness in shale formation would be obtained based on the well logging data, which can be used to summarize the spatial distribution characteristics of the fracture toughness in the shale formation. However, it is difficult to obtain transverse distribution characteristics of fracture toughness in shale formation based solely on the well logging data. Therefore, in order to investigate the spatial distribution of the fracture toughness, jointing well logging and seismic method could be adopted to quantitatively predict the fracture toughness in shale formation. The results show that fracture toughness of shales is sensitive to acoustic interval transit time and wave impedance. The prediction model of the fracture toughness of shales was constructed, which had a good prediction effect. The fracture toughness values of shales from the Upper Silurian Wufeng-Longmaxi Formation were larger, whereas those of shales from the Lower Silurian Wufeng-Longmaxi Formation were lower. The fracture toughness is mainly distributed in strips along the vertical direction while the distribution area is continuous in the lateral direction, indicating that it has obvious stratification characteristics.

APA, Harvard, Vancouver, ISO, and other styles

30

Kim, Min Chul, Bong Sang Lee, Won Jon Yang, and Jun Hwa Hong. "Determination of the Key Microstructural Parameter for the Cleavage Fracture Toughness of Reactor Pressure Vessel Steels in the Transition Region." Key Engineering Materials 297-300 (November 2005): 1672–77. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1672.

Full text

Abstract:

The effects of the microstructural parameters, such as the prior austenite grain size and carbide size, on the cleavage fracture toughness were investigated in the transition region of Mn-Mo-Ni bainitic low alloy steels. Cleavage fracture toughness was evaluated by the ASTM standard E 1921 Master curve method. In order to clarify the effects of each microstructure, the grain size and carbide size of the test materials were independently controlled by modifying the heat treatment process. Firstly, the grain sizes were changed from 25㎛ to 110㎛ without any significant changes in the carbide size and shape. Secondly, the average carbide sizes were changed from 0.20 ㎛ to 0.29㎛ but maintaining the initial grain sizes. As a result, the fracture toughness in the transition region did not show any significant dependency on the austenite grain size, while the carbide size showed a close relation to the fracture toughness. Fracture toughness was decreased with an increase of the average carbide size. From the microscopic observation of the fractured surface, the cleavage initiation distance (CID) from the original crack tip showed no direct relationship to the prior austenite grain sizes but a strong relationship to the carbide sizes. However, the measured cleavage fracture toughness was strongly related to the distance from the crack tip to the cleavage initiation site. From the viewpoint of the weakest link theory, the particle size and their distribution in front of the crack tip is probably more important than the grain size in the transition temperature range where the fracture was controlled by the cleavage crack initiation.

APA, Harvard, Vancouver, ISO, and other styles

31

Lee, Jung Suk, Jae Il Jang, Keun Bong Yoo, and Dong Il Kwon. "Evaluation of Fracture Toughness for Power Plant Materials Using Continuous Indentation Technique." Key Engineering Materials 321-323 (October 2006): 480–85. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.480.

Full text

Abstract:

An indentation fracture toughness model is applied to estimate non-destructively the fracture toughness of power plant materials such as ASTM A53 and ASME SA335 P91. Fracture toughness evaluated using the model showed good agreement with current standard fracture toughness test results.

APA, Harvard, Vancouver, ISO, and other styles

32

Wang, Hai Long, Chun Ling Guo, and Xiao Yan Sun. "Effect of Calcium Dissolution on the Fracture Properties of Concrete Exposed to Nitric Acid Environment." Advanced Materials Research 374-377 (October 2011): 1974–78. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1974.

Full text

Abstract:

The effect of calcium leaching by nitric acid on fracture properties of concrete was experimentally studied. The double-K fracture parameters were investigated using three-point bending beams, and the deterioration regularity of fracture properties of concrete chronically attacked by nitric acid was gotten on basis of these results. The load-crack mouth opening displacement curves under different nitric attack periods were obtained by pasting some strain gauges onto the pre-crack tip. On basis of the double-K criterion, the unstable fracture toughness as well as the initial fracture toughness was calculated according to the critical crack mouth opening displacement, the unstable fracture load and initial cracking load which can be obtained from the test. The experimental results indicated that the ratio of the initial fracture toughness to the unstable fracture toughness varied between 0.47 and 0.61 approximately. Both of the unstable fracture toughness and the initial fracture toughness decrease with attack period especially during the early 60 days, then drop to a stable trend gradually. In addition, the initial fracture toughness is less sensitive to acid attack compared with the unstable fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

33

Parasuraman, Prabhuraj, Tushar Sonar, and Selvaraj Rajakumar. "Microstructure, tensile properties and fracture toughness of friction stir welded AA7075-T651 aluminium alloy joints." Materials Testing 64, no. 12 (November 29, 2022): 1843–50. http://dx.doi.org/10.1515/mt-2022-0212.

Full text

Abstract:

Abstract The main objective of this investigation is to study the microstructure, tensile properties and fracture toughness of friction stir welded (FSW) butt joints of 10 mm thick AA7075-T651 plates. The microstructural features of stir zone (SZ), thermos-mechanically affected zone (TMAZ), heat affected zone (HAZ) were analyzed using optical microscopy technique. The tensile properties were evaluated using smooth and notch tensile specimens and compared to base metal properties. The microhardness survey was done across the weld cross section and correlated to the failure of tensile specimens. Compact tension (CT) specimens were used to evaluate the fracture toughness of welded joints. The fractured tensile and CT specimens were analyzed using scanning electron microscopy (SEM). Results showed that the FSW AA7075-T651 specimens welded using axial load of 12 kN, tool rotation speed of 750 rpm and welding speed of 30 mm/min exhibited 412 MPa tensile strength and 9% elongation. It showed 88 and 89% of base metal strength elongation. The joints showed fracture toughness of 23 MPa m1/2 which is 80% of base metal fracture toughness. The superior tensile and fracture toughness properties of joints are mainly attributed to the evolution of finer grains in SZ due to the stirring action of FSW tool.

APA, Harvard, Vancouver, ISO, and other styles

34

Lanning, David B., and M. H. Herman Shen. "Reliability of Welded Structures Containing Cracks in Heat-Affected Zones." Journal of Offshore Mechanics and Arctic Engineering 122, no. 4 (March 3, 2000): 225–32. http://dx.doi.org/10.1115/1.1289288.

Full text

Abstract:

This study investigates the reliability of a plate containing a semi-elliptical surface crack intersecting regions of dissimilar material properties. A weakest-link model is developed to express fracture toughness distributions in terms of effective crack lengths that account for the varying stress intensity factor along the crack front. The model is intended to aid in the development of fracture toughness distributions for cracks encountering local brittle zones (LBZ) in the heat-affected zones (HAZ) of welded joints, where lower-bound fracture toughness values have been measured in the laboratory when a significant portion of the crack front is intersecting the coarse-grained LBZs. An example reliability analysis is presented for a surface crack in a material containing alternating bands of two Weibull-distributed toughnesses. [S0892-7219(00)01203-6]

APA, Harvard, Vancouver, ISO, and other styles

35

Ku, H., W. Xiang, and N. Pattarachaiyakoop. "Mathematical Modeling of the Fracture Toughness of Phenol Formaldehyde Composites Reinforced with E-Spheres." Advanced Materials Research 79-82 (August 2009): 1165–68. http://dx.doi.org/10.4028/www.scientific.net/amr.79-82.1165.

Full text

Abstract:

The fracture toughness of SLG filled phenolic composites have been determined by short bar tests. It is expensive to prepare the samples for the tests. Therefore, it is necessary to develop a mathematical model that will predict the fracture toughness of particulate filled phenolic composites. Mathematical models for tensile strength, Young’s modulus are available but not for impact strength and fracture toughness. There is no sign that it can be built up from simple mathematical model; polynomial interpolation using Lagrange’s method was therefore employed to generate the fracture toughness model using the data obtained from experiments. From experiments, it was found that the trend of the fracture toughness of the samples cured conventionally was similar to that cured in microwaves; it is therefore possible to predict the fracture toughness of the samples cured in microwaves from shifting the mathematical model generated for fracture toughness of samples post-cured in conventional oven. The shifted model represented the fracture toughness of the samples cured in microwaves vey well.

APA, Harvard, Vancouver, ISO, and other styles

36

Li, Kairui, Nickolay N. Smirnov, Chengzhi Qi, Mingyang Wang, Dmitry A. Pestov, and Anastasia A. Shamina. "A Planar-3D Mathematical Model for Studying the Effect of Heterogeneity of Rock Fracture Toughness on Hydraulic Fracture Propagation: Early-Time Solution including the Stage before Propagation." Mathematics 11, no. 9 (April 27, 2023): 2083. http://dx.doi.org/10.3390/math11092083.

Full text

Abstract:

Among the studies of the effect of rock’s heterogeneity on hydraulic fracture propagation, very little information on the effects of the heterogeneity of rock’s fracture toughness is available. The objective of the present paper is to develop a planar-3D model for studying the effect of the heterogeneity of rock’s fracture toughness on hydraulic fracture propagation. Not only the stage of fracture propagation, but also the stage before the fracture propagation is considered in this model. Based on the proposed model, the evolution of hydraulic fracture propagation under a typical heterogeneous distribution of rock’s fracture toughness and the solution at the stage before fracture propagation are analyzed in detail. Furthermore, a series of numerical comparison experiments including five different distributions of rock’s fracture toughness are made in order to study the effect of the heterogeneity of rock’s toughness. The results indicate that the minimum fracture radius and the contrast of rock’s fracture toughness between adjacent layers are important parameters for determining the size and location of the maximum fracture opening. Most importantly, the fracture contour is greatly affected by the heterogeneity of rock’s fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

37

Bisht, Neeraj, and Prakash Chandra Gope. "Effect of rice husk (treated/untreated) and rice husk ash on fracture toughness of epoxy bio-composite." Journal of the Mechanical Behavior of Materials 29, no. 1 (January 1, 2020): 177–85. http://dx.doi.org/10.1515/jmbm-2020-0018.

Full text

Abstract:

Abstract Present work studies the effect of particle reinforcement on fracture toughness of bio-composites. The filler used has been taken as rice husk. Epoxy resin has been taken as matrix material. Composites with varying filler loading of 10, 20, 30 and 40 wt.% were fabricated. The fracture toughness was seen to be increasing with increase in filler loading. However beyond 20% there was a decrease in fracture toughness with increase in filler loading. The effect of fibre treatment on toughness was also observed. Rice husk fibres pre-treated with NaOH were used. It was observed that fracture toughness further improved due to treatment. The increase in fracture toughness was significant. Fracture toughness increased from 1.072 to 2.7465 MPa√mm for 20% reinforcement and after treatment it increased to 2.876 MPa√mm. It was observed that concentration of treatment media also affects the fracture toughness. Further the effect of hybridization was observed by addition of rice husk ash as a secondary reinforcement. The fracture toughness of the resulting composites was remarkably higher than that of pure epoxy.

APA, Harvard, Vancouver, ISO, and other styles

38

Karthikeyan, Vasudevan, Naveen Gopi Chander, Jetti Ramesh Reddy, and Balasubramanium Muthukumar. "Effects of incorporation of silver and titanium nanoparticles on feldspathic ceramic toughness." Journal of Dental Research, Dental Clinics, Dental Prospects 13, no. 2 (August 14, 2019): 98–102. http://dx.doi.org/10.15171/joddd.2019.015.

Full text

Abstract:

Background. Porcelain is brittle and in many situations it requires replacement in fractured or chipped restorations. The prospects exist in improving the strength of feldspathic porcelain to widen its applications. This study evaluated the fracture toughness of feldspathic porcelain after incorporation of silver and titanium nanoparticles at varying concentrations (0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%). Methods. Test specimen dimensions were standardized to ASTM C1421–16 standards and a three-point flexure test was carried out to evaluate fracture toughness. A total of 330 samples were fabricated and broadly divided into three groups. Group I (titanium nanoparticles) and group II (silver nanoparticles) were further subdivided into 5 groups (0 wt%, 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%) for fracture toughness analysis, with each group consisting of 30 samples. Group III contained the superior concentration of both titanium and silver nanoparticles. The fracture toughness (KIC) was calculated using indentation fracture method and microstructure observations were made using scanning electron microscopy. The KIC values were compared and evaluated using one-way ANOVA. Results. Data were analyzed using one-way ANOVA and Tukey’s HSD post hoc test multiple comparisons. The mean values of group I, group II and group III were 1.949 MPa.m1/2, 2.002 MPa.m1/2 and 1.330 MPa.m1/2 , respectively. Conclusion. The results revealed that the samples reinforced with titanium and silver nanoparticles showed significant increases in fracture toughness. The blending of superior concentration of both titanium and silver nanoparticles decreased fracture resistance.

APA, Harvard, Vancouver, ISO, and other styles

39

Zhou, Yu Mei, Feng Lin Zhang, Peng Cheng Li, Kun Bai, and Shang Hua Wu. "A Study on Ultra-Hard AlMgB₁₄ Modified by TiB₂ and Ni₃Al." Materials Science Forum 848 (March 2016): 607–12. http://dx.doi.org/10.4028/www.scientific.net/msf.848.607.

Full text

Abstract:

AlMgB14 is a very hard and brittle material which need be modified for utilizing as cutting tool materials. In present study, TiB2 and Ni3Al were used to strengthen and toughen AlMgB14 material. The microstructure of the AlMgB14-TiB2-Ni3Al composites was analysized by scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and an X-ray diffractometer (XRD). The hardness and fracture toughness of the AlMgB14-TiB2Ni3Al composites were also examined. The results showed that the major phases in AlMgB14-Ni3Al composites were TiB2, AlMgB14, MgAl2O4 , Ni3Al and NiAl. With the increasing of the amount of Ni3Al, more intergranular fractured features can be found in the fractured surface of the composites, the hardness and fracture toughness of the composites were both decreased comparing to the synthesised AlMgB14. The AlMgB14-TiB2-4wt.% Ni3Al composite has a hardness of 28.1 Gpa and a fracture toughness of 3.14 MPa·m1/2.

APA, Harvard, Vancouver, ISO, and other styles

40

Zhu, Lun. "Experimental Study by Using Drilling Core Materials Inversion Formation Rock Fracture Toughness Test Research." Applied Mechanics and Materials 538 (April 2014): 315–18. http://dx.doi.org/10.4028/www.scientific.net/amm.538.315.

Full text

Abstract:

On the basis of Cliftons, hydraulic fracturing is established under the condition of cylindrical specimen fracture toughness expression. Using a self-built laboratory equipment, drilling core specimen for the fracture toughness test and obtain the relevant data. Based on the rock parameters inversion theory to construct the formation rock fracture toughness inversion objective function and optimization function. according to the drilling core material fracture toughness test data and the application of Matlab programming presented the formation rock fracture toughness.

APA, Harvard, Vancouver, ISO, and other styles

41

Mutoh, Y., N. Miyahara, K. Yamaishi, and T. Oikawa. "High Temperature Fracture Toughness in Silicon Nitride and Sialon." Journal of Engineering Materials and Technology 115, no. 3 (July 1, 1993): 268–72. http://dx.doi.org/10.1115/1.2904217.

Full text

Abstract:

Fracture Toughness of HIP-sintered silicon nitride decreased with increasing temperature up to 1200°C. The brittle-to-ductile transition was observed in the temperature range from 1200°C to 1275°C: the fracture toughness rapidly increased in the transition region. Above the transition temperature, the fracture toughness decreased with increasing temperature. Fracture toughness of sialon increased with increasing temperature. Transition of fracture mechanism was observed in sialon around 1300°C. The differences of temperature dependence of fracture toughness between two materials are interpreted in terms of the effects of grain-boundary glass phase on fracture.

APA, Harvard, Vancouver, ISO, and other styles

42

Nakano, Yoshifumi. "Fracture Toughness of Steels." Journal of the Japan Welding Society 61, no. 6 (1992): 464–68. http://dx.doi.org/10.2207/qjjws1943.61.6_464.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Shiwa, Mistuharu, and Teruo Kishi. "Fracture toughness of ceramics." Bulletin of the Japan Institute of Metals 27, no. 8 (1988): 644–49. http://dx.doi.org/10.2320/materia1962.27.644.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Zinkham, R. E. "Fracture Toughness in Weldments." Journal of Pressure Vessel Technology 107, no. 1 (February 1, 1985): 98. http://dx.doi.org/10.1115/1.3264416.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Noda, Toshiharu, Tomohito Iikubo, and Susumu Isobe. "Fracture toughness of TiAl." DENKI-SEIKO[ELECTRIC FURNACE STEEL] 61, no. 2 (1990): 102–9. http://dx.doi.org/10.4262/denkiseiko.61.102.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Siriwardane, Hema J., and Abbie W. Layne. "Fracture toughness of geomaterials." International Journal for Numerical and Analytical Methods in Geomechanics 13, no. 2 (March 1989): 199–205. http://dx.doi.org/10.1002/nag.1610130207.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Pokluda, Jaroslav, Ivo Dlouhý, Marta Kianicová, Jan Čupera, Jana Horníková, and Pavel Šandera. "Temperature Dependence of Fracture Characteristics of Variously Heat-Treated Grades of Ultra-High-Strength Steel: Experimental and Modelling." Materials 14, no. 19 (October 7, 2021): 5875. http://dx.doi.org/10.3390/ma14195875.

Full text

Abstract:

The temperature dependence of tensile characteristics and fracture toughness of the standardly heat-treated low-alloyed steel OCHN3MFA along with three additionally heat-treated grades was experimentally studied. In the temperature range of ⟨−196; 22⟩ °C, all the additional heat treatments transferred the standard steel from a high- to ultra-high strength levels even with improved tensile ductility characteristics. This could be explained by a reduction of the inclusion content, refinement of the martensitic blocks, ductile retained austenite content, and homogenization of the shape ratio of martensitic laths as revealed by metallographic, X-ray, and EBSD techniques. On the other hand, the values of the fracture toughness of all grades were found to be comparable in the whole temperature range as the cause of a high stress triaxiality in the pre-cracked Charpy V-notch samples. The values of the fracture toughness of the standard steel grade could be predicted well using the fracture model proposed by Pokluda et al. based on the tensile characteristics. Such a prediction failed in the case of additionally heat-treated grades due to the different temperature dependence of the fracture mechanisms occurring in the tensile and fracture-toughness tests. While the tensile samples fractured in a ductile-dimple mode at all temperatures, the fracture-toughness specimens exhibited a transition from the ductile to quasi-brittle fracture mode with decreasing temperature. This transition could be interpreted in terms of a transfer from the model proposed by Rice and Johnson to the model of Tvergaard and Hutchinson.

APA, Harvard, Vancouver, ISO, and other styles

48

Li, Jun, Fengchi Wang, Fu Yi, Jie Ma, and Zhenhuan Lin. "Fractal Analysis of the Fracture Evolution of Freeze-Thaw Damage to Asphalt Concrete." Materials 12, no. 14 (July 17, 2019): 2288. http://dx.doi.org/10.3390/ma12142288.

Full text

Abstract:

AC (asphalt concrete)-13, as the main material used in pavement construction, has been applied widely in seasonal frozen areas. In order to understand the fracture mechanism in the freeze-thaw (F-T) damage process, the mesoscale structure of AC-13 is obtained by computed tomography (CT). The fractal dimension of cracks is used as a damage evaluation index. Most previous studies have only focused on the fractal dimensions of whole cracks, while ignoring the fractal tectonic process and the self-similarity degree of a single fracture. Therefore, in this study, the intrinsic mechanism of fractures and damage were investigated. In addition, the critical crack stress and fracture toughness models of a single fracture in a freeze-thaw damage process are established for AC-13. The results indicate that in terms of the critical crack stress and fracture toughness, with the increase of F-T times, there is an obvious decreasing trend. The fracture model can effectively describe the fracture toughness calculated by ABAQUS in the process of freeze-thaw cycles.

APA, Harvard, Vancouver, ISO, and other styles

49

Lee, Soo Hyun, Jink Wang Kim, Su Nam Kim, Sang Bong Cho, and Jon Do Yun. "Interfacial Fracture Toughness for Film on Substrate Determined by Indentation Method." Key Engineering Materials 345-346 (August 2007): 801–4. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.801.

Full text

Abstract:

Indentation method was used to determine the interfacial fracture toughness of epoxy coating on aluminum substrate. Tensile testing followed by finite element analysis was also performed to determine the interface fracture toughness. Fracture toughness values determined by two methods were consistent, giving reliability to indentation method for interfacial fracture toughness measurement.

APA, Harvard, Vancouver, ISO, and other styles

50

Ripling, E. J., and P. B. Crosley. "Full-Thickness Crack Arrest Fracture Toughness of 9-Percent Ni (ASTM 553, Type 1) Steels." Journal of Pressure Vessel Technology 113, no. 3 (August 1, 1991): 375–79. http://dx.doi.org/10.1115/1.2928769.

Full text

Abstract:

Measurements were made of the full-thickness crack arrest fracture toughness (FTCAT) of three 9-percent Ni steels having the range of thicknesses and Charpy V-notch toughnesses of plates now in LNG storage tank service. Unlike the plates used in large pressure vessels, these thinner plates do not crack under a condition of plane strain, so that test method ASTM E1221 “Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, Kla, of Ferritic Steels,” was modified for these tests. The toughness of all three steels was measured at liquid nitrogen temperature (−196C), but two of the three were too tough to be measured at LNG storage temperature (−162C). Even the least tough plate had a high enough toughness to arrest long cracks in LNG storage service.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Fracture toughness'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles