Fracture Toughness Of Some Materials Used In Fabricating Fixed Offshore Structures

1981 ◽  
Author(s):  
H.G. Pisarski
Keyword(s):  
Fracture Toughness ◽  
Offshore Structures ◽  
Materials Used

Scaling of Pop-Ins During Brittle Fracture Testing

2019 ◽  
Author(s):  
O. J. Coppejans ◽  
C. L. Walters
Keyword(s):  
Fracture Toughness ◽  
Analytical Method ◽  
Offshore Structures ◽  
Specimen Size ◽  
Small Scale ◽  
Unstable Fracture ◽  
Displacement Curve ◽  
Fracture Toughness Test ◽  
Key Factor

Abstract Measurement of the fracture toughness of steel is important for the assurance of the safety of ships and offshore structures, especially when these structures are made of thick sections and/or applied in cold environments. One key factor that will affect the determination of the fracture toughness is a pop-in, which is a short event in which unstable fracture is initiated and then self-arrests. If the pop-in is large enough, it will be used to calculate the fracture toughness. Pop-ins are believed to be the products of local brittle zones, which occur randomly at crack tips and have finite sizes. Fracture toughness testing codes have ways of determining whether a pop-in is critical (thus, identifying the maximum force and displacement to be used in the determination of the toughness of the material) or not important (thus, allowing for the test to proceed). In an ongoing project on the use of small-scale fracture specimens to predict standard fracture toughness test results, we would like to know how pop-in acceptance criteria should be scaled for specimen size. It is expected that the physical size of the brittle zones that cause pop-ins is invariant of specimen size, meaning that the contribution of the pop-in will be proportionally more important for smaller specimens. An analytical method for relating the pop-ins on one specimen size to another specimen size is developed. This method is partially verified by observations on the size of a local brittle zone observed on a fracture surface and the effect of that pop-in on the force-displacement curve during a CTOD test. The analytical method showed that an equivalent pop-in for a small-scale specimen is indeed larger, but that the effect was subtle.

Preparation and Study of Flexural Strength and Impact Strength for Hybrid Composite Materials used in Structural Applications

2020 ◽  
Vol 38 (8A) ◽  
pp. 1117-1125
Author(s):  
Teeb A. Mohameed ◽  
Sihama I. Salih ◽  
Wafaa M. Salih
Keyword(s):  
Fracture Toughness ◽  
Impact Strength ◽  
Flexural Strength ◽  
Polymer Blends ◽  
Laminar Composite ◽  
Kevlar Fiber ◽  
Laminar Composites ◽  
Structural Applications ◽  
Materials Used ◽  
The Impact

 Many of the polymeric materials used for structural purposes have weak mechanical properties, these characteristics can therefore be improved by preparing a hybrid laminar composite. In this work use melting mixing method using screw extruder to prepare sheets of polymer blends and nanocomposites based on polymer blends, and using a hot hydraulic press machine to prepared hybrid laminates composites. Two groups of hybrid laminar composites were prepared, the first group is consist of [((94%PP: 5%PMMA: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF] and the second group is [((94%PP: 5%UHMWPE: 1 %( PP-g-MA)): 0.3% ZrO2): 6%KF and 8%KF]. The results illustrated the impact strength and fracture toughness are increase with increased weight percentage of Kevlar fiber in for both groups of laminar composites and the highest values for two groups are (58.1, 54.95 KJ/M2) and (8.4, 9.16 MPa√m) respectively, any that, at the rate of increment reached to (120.4%, 107%) and (52.7%, 66.5%) respectively, compared with the neat PP. Moreover, the flexural strength values of the first group samples of hybrid laminar composite remained constant, when added kevlar fiber to nanocomposite. While, the flexural strength values of the second group samples of hybrid laminar composite increase with increase the ratio of kevlar fiber in composite to reach the maximum values (92 MPa) at 8% wt. of kevlar fiber, any, at the rate of increment reached to 39.4% compared with the neat PP. As well as, the results shown that the flexural properties and fracture toughness of the second group samples higher than they are for the first group samples.

Development of Laser and Photodefinable Toughened Benzocyclobutene Dielectric Materials for 3D-TSV Integration

2013 ◽  
Vol 2013 (1) ◽  
pp. 000067-000071
Author(s):  
Zidong Wang ◽  
Michael Gallagher ◽  
Kevin Wang ◽  
Elissei Iagodkine ◽  
Mark Oliver ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Moisture Absorption ◽  
Dielectric Materials ◽  
Copper Interconnects ◽  
Size Factor ◽  
Low Loss ◽  
Low Dielectric ◽  
Materials Used ◽  
Signal Routing ◽  
Stress Buffer

3D IC integration based on TSV technology has been recognized as a key enabler for next generation of electronic devices with reduced size factor and improved performances. The adoption of 3D-TSV technology also requires the development of innovative interconnect solutions that reduces the size of signal routing and therefore imposes new demands on dielectric materials used to isolate the copper interconnects. Benzocyclobutene polymers (Dow's CYCLOTENE™ Advanced Electronic Resins) have been used to isolate copper interconnects in packaging applications for more than 20 years, due to a number of good attributes of the BCB polymer including low copper drift rate, low dielectric constant and low loss, low moisture absorption and proven reliability. However, the low fracture toughness and low elongation of BCB polymer has limited its use in stress buffer applications due to solder bump failure. Here we report the development of new laser and photodefinable toughened benzocyclobutene (BCB) dielectric materials that have following improved properties and benefits over commercial materials including: 1) Higher elongation to break at 25%, 2) Higher fracture toughness, 3) Improved lithographic performance, < 8μm minimal size feature, 4) Better stability, no change in Eo after 30 days at room temperature. The patterning and integration of these toughened benzocyclobutene materials and the processing conditions are also discussed. We believe this toughened BCB material will find wide applications as a stress buffer layer in 3-D IC.

Tribological Aspects of AlN-TiN Thin Composite Films

2004 ◽  
Vol 843 ◽  
Author(s):  
C. Waters ◽  
G. Young ◽  
S. Yarmolenko ◽  
X. Wang ◽  
J. Sankar
Keyword(s):  
Fracture Toughness ◽  
Critical Load ◽  
Composite Films ◽  
Scratch Test ◽  
Small Scale ◽  
Wear Properties ◽  
Multilayered Structures ◽  
Tin Film ◽  
Materials Used ◽  
Increasing Load

AbstractPhysical properties, and the friction and wear are important issues in small-scale applications, it is therefore essential that the materials used have good micromechanical and tribological properties. The adhesion, fracture toughness and wear properties of AlN-TiN thin composite films is being investigated in this study. The multilayered structures are generated using Pulsed Laser Deposition (PLD). The durability and functionality of thin films is subject to the adhesion between the coating and the underlying substrate in addition to it's resistance to cracking. The magnitude of the critical load during a scratch test is related to the adhesion of the substrate to the coating. In this test a Berkovich indenter is used for measurements and is drawn across the surface of a coating under an increasing load. The magnitude of the critical load will be studied for various films from a monolayer TiN film to different AlN-TiN films and those relative results compared to their facture toughness and their wear properties. Despite the adhesion, the critical load depends on several other parameters including the friction coefficient. The critical characteristic load is shown to depend on the number of layers and the relative AlN-TiN thickness. The fracture toughness showed a weak dependence on the layer characteristics.

scholarly journals A New Approach to Evaluate Fracture Toughness of Structural Materials

2003 ◽  
Author(s):  
J. A. Wang ◽  
K. C. Liu
Keyword(s):  
Fracture Toughness ◽  
Three Dimensional ◽  
Torsion Test ◽  
Computer Code ◽  
Structural Materials ◽  
New Approach ◽  
Dimensional Finite Element ◽  
Toughness Testing ◽  
Materials Used ◽  
Three Dimensional Finite Element

A new method, designated as Spiral Notch Torsion Test (SNTT), is developed recently to measure the intrinsic fracture toughness (KIC) of structural materials. The SNTT overcomes many of the limitations inherent in traditional techniques and makes it possible to standardize fracture toughness testing. It is uniquely suitable for testing a wide variety of materials used extensively in pressure vessel and piping structural components and weldments, including others such as ceramics, their composites, and concrete. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45° pitch. The KIC values are obtained with the aid of a three-dimensional finite-element computer code, TOR3D-KIC, developed at ORNL.

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.

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.

A New Test Method for Determining the Strength and Fracture Toughness of Cement Mortar and Concrete

2009 ◽  
Author(s):  
John Jy-An Wang ◽  
Ken C. Liu ◽  
Dan Naus
Keyword(s):  
Fracture Toughness ◽  
Three Dimensional ◽  
Computer Code ◽  
Cementitious Materials ◽  
Test Method ◽  
Fracture Toughness Test ◽  
Dimensional Finite Element ◽  
Materials Used ◽  
Torsion Fracture ◽  
Three Dimensional Finite Element

The Spiral Notch Torsion Fracture Toughness Test (SNTT) was developed recently to determine the intrinsic fracture toughness (KIC) of structural materials. The SNTT system operates by applying pure torsion to uniform cylindrical specimens with a notch line that spirals around the specimen at a 45° pitch. KIC values are obtained with the aid of an in-house developed three-dimensional finite-element computer code, TOR3D-KIC. The SNTT method is uniquely suitable for testing a wide variety of materials used extensively in pressure vessel and piping structural components and weldments. Application of the method to metallic, ceramic, and graphite materials has been demonstrated. One important characteristic of SNTT is that neither a fatigue precrack nor a deep notch are required for the evaluation of brittle materials, which significantly reduces the sample size requirement. In this paper we report results for a Portland cement-based mortar to demonstrate applicability of the SNTT method to cementitious materials. The estimated KIC of the tested mortar samples with compressive strength of 34.45 MPa was found to be 0.19 MPa √m.

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