The Validity of Standard Test Methods for Characterizing Weld Fracture

1992 ◽  
Vol 114 (1) ◽  
pp. 16-21 ◽  
Author(s):  
S. M. Graham ◽  
W. G. Reuter ◽  
W. R. Lloyd ◽  
J. S. Epstein
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Linear Elasticity ◽  
Test Methods ◽  
Standard Test ◽  
Heterogeneous Structure ◽  
Displacement Fields ◽  
Standard Methods ◽  
Fracture Parameters ◽  
Homogeneous Materials

Standard methods for testing fracture toughness of homogeneous materials are currently being applied to welds. A weld is, by nature, a heterogeneous structure containing zones with different microstructures and mechanical properties. The validity of using fracture parameters developed for homogeneous materials to characterize fracture of welds has not been established. Tests were conducted to investigate whether the extension of a crack along an interface is governed by the same fracture parameters used to predict fracture in homogeneous materials. The tests involved measuring the displacement fields around a crack tip in the interface between two materials with matched elastic properties and differing yield strengths. The form of the displacement distribution was then compared with the theoretical displacements for linear elasticity and nonlinear elasticity with power-law hardening.

Fracture toughness of NiTi–Towards establishing standard test methods for phase transforming materials

2019 ◽  
Vol 162 ◽  
pp. 226-238 ◽  
Author(s):  
Behrouz Haghgouyan ◽  
Ceylan Hayrettin ◽  
Theocharis Baxevanis ◽  
Ibrahim Karaman ◽  
Dimitris C. Lagoudas
Keyword(s):  
Fracture Toughness ◽  
Test Methods ◽  
Standard Test

Methods to Determine Low-Constraint Fracture Toughness: Review and Progress

2016 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Fracture Toughness ◽  
Test Methods ◽  
Standard Test ◽  
Initiation Toughness ◽  
Fracture Toughness Test ◽  
Crack Tip Opening Displacement ◽  
Test Procedures ◽  
Opening Displacement ◽  
Resistance Curves ◽  
Low Constraint

Fracture toughness is often described by the J-integral or crack-tip opening displacement (CTOD) for ductile materials. ASTM, BSI and ISO have developed their own standard test methods for measuring fracture initiation toughness and resistance curves in terms of the J and CTOD using bending dominant specimens in high constraint conditions. However, most actual cracks are in low constraint conditions, and the standard resistance curves may be overly conservative. To obtain more realistic fracture toughness for actual cracks in low-constraint conditions, different fracture test methods have been developed in the past decades. To facilitate understanding and use the test standards, this paper presents a critical review on commonly used fracture toughness test methods using standard and non-standard specimens in reference to the fracture parameters J and CTOD, including (1) ASTM, BSI and ISO standard test methods, (2) constraint correction methods for formulating a constraint-dependent resistance curve, and (3) direct test methods using the single edge-notched tension (SENT) specimen. This review discusses basic concepts, basic methods, estimation equations, test procedures, historical efforts and recent progresses.

Determination of the Fracture Toughness Parameters for an MDF Cement Composite

1985 ◽  
Vol 64 ◽  
Author(s):  
M. Arzamendi ◽  
R. L. Sierakowski ◽  
W. E. Wolfe
Keyword(s):  
Fracture Toughness ◽  
Cement Composite ◽  
Compact Tension ◽  
Test Methods ◽  
Standard Test ◽  
Elastic Behavior ◽  
Hardened Cement ◽  
Linear Elastic ◽  
Toughness Testing

ABSTRACTThe experimental results of fracture toughness testing of a Macro Defect (MDF) Free cement are presented. The material, a hydraulic cement with hydrolyzed polyvinyl polymers, behaves much like a hardened ceramic with measured maximum compressive and tensile strengths of 380 MN/m2 and 69 MN/m2 respectively. Fracture toughness tests were performed on compact tension (CT) and single edge notched beam (SENB) specimens cut from test panels which were supplied in 3mm, 5mm and 10mm thicknesses. The results were evaluated with respect to the fracture toughness parameter Kic using a modification of standard test methods as determined by observed natural behavior. The MDF material exhibited an essentially linear elastic behavior with a fracture toughness slightly higher than typical values recorded for hardened cement paste.

scholarly journals Single Edge Notch Bend (SENB) of Kenaf/Fibreglass Hybrid Composites

2019 ◽  
Vol 8 (4) ◽  
pp. 6967-6971
Keyword(s):  
Fracture Toughness ◽  
Outer Layer ◽  
Hybrid Composites ◽  
Strain Energy Release ◽  
Weight Fraction ◽  
Natural Fibre ◽  
Test Methods ◽  
Standard Test ◽  
Single Edge ◽  
Layer Arrangement

Kenaf is known for many years as a typical crop that can be used in various applications such as in automotive, and building structure. Along with the depletion and environmental issues raised nowadays by excessively used of man-made synthetic fibres make the natural fibre to become popular and favourable to be implemented. This paper discusses on the development of long kenaf fibre reinforced polyester matrix composite. Total weight of about 40% fibre fraction was selected. In this study, the addition of about 10% weight fraction of fibreglass in the composite system is needed in order to strengthen the composite material and also to retain its reliability and robustness in their applications. Thus, preparation of two different layer arrangement of kenaf and fibreglass were conducted viz. (i) kenaf at inner layer and fibreglass at outer layer ([0o 90o ]K/FG2p/[90o 0 o ]k [0o 90o ]K) (ii) kenaf at outer layer and fibreglass at inner layer (FG/[0o 90o /90o 0 o ]K/FG). All configuration samples were fabricated by hand lay-up and cold press technique. Fracture toughness testing was carried out using a single edge notched bend specimen at a loading rate of 10mm/min. All samples were prepared according to ASTM D5045 (Standard Test Methods for Plane-Strain Fracture Toughness and Strain Energy Release Rate of Plastic Materials). Results obtained from SENB test were then evaluated and discussed. It can be used as a guideline or reference for further research on this type of polymer composite.

scholarly journals Assessment of metals fabricability by pressure

2020 ◽  
Vol 63 (6) ◽  
pp. 481-483
Author(s):  
G. A. Orlov ◽  
A. G. Orlov
Keyword(s):  
Mechanical Properties ◽  
Metal Forming ◽  
Quantitative Assessment ◽  
Energy Intensity ◽  
Test Methods ◽  
Standard Test ◽  
Geometrical Mean ◽  
Data Estimation ◽  
Standard Tests ◽  
Made In

A variant of quantitative assessment of metals fabricability by pressure is offered according to the standard tests on mechanical properties. The complex parameter is used, defined as geometrical mean of three parameters characterizing plasticity, hardening and energy intensity of alloys deformation. Relations of scientific and engineering characteristics of deformability assessment for the use of scientific researches results in factory practice are determined, being guided on the standard test methods. Examples of the use of received equations are resulted for a number of steels in processes of metal forming. Testing of the proposed method was carried out according to the known data. Estimation of the complex parameters was made in accordance with Harrington desirability scale. The offered technique can be used for an assessment of fabricability of new steels and alloys.

scholarly journals Mechanically Superior Molybdenum Rhenium (MoRe®) Alloy provides an advanced option for Foot and Ankle Implants

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0037 ◽  
Author(s):  
Selene Parekh ◽  
Samuel Adams ◽  
James Nunley ◽  
Mark Easley ◽  
David Pedowitz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surgical Techniques ◽  
Biomechanical Properties ◽  
Delayed Union ◽  
Test Methods ◽  
Standard Test ◽  
Great Promise ◽  
Foot And Ankle ◽  
Repetitive Stress ◽  
Design Options

Category: Other Introduction/Purpose: One of the most common complications in orthopaedic surgery of the foot and ankle is nonunion or delayed union and bone or implant fractures. Although foot and ankle surgery has improved dramatically over the past decades primarily due to the development of better techniques, little progress has been made in the development of new materials for implants. Titanium, the most commonly used alloy for foot and ankle implants, has limited strength and is notch-sensitive so repetitive stress leads to fatigue failure of implants and limits design options. Better materials with optimized biomechanical properties could result in the development of superior foot and ankle implants and surgical techniques. The mechanical properties of Molybdenum-Rhenium (MoRe®), a promising new alloy for foot and ankle implants were tested. Methods: Standard test methods (ASTM 1717) were performed to evaluate the mechanical properties of Molybdenum Rhenium (MoRe®) alloy compared to Titanium (Ti-6Al-4 V, ASTM F136-13 annealed bar, Ti-ELI). Results: MoRe® is composed purely (99.99%) of molybdenum and rhenium and does not contain Nickel. Molybdenum is found in food and is a cofactor to the enzymes xanthine oxidase and sulfite oxidase, which are essential to bone and connective tissue metabolism. Rhenium is an inert metal with no biological affect. Mechanical testing showed MoRe to be superior to Titanium: Yield Strength: MoRe® 280ksi, Titanium 115ksi, Ultimate Tensile Strength: MoRe® 300ksi, Titanium 125 ksi. Elongation and Reduction in Area: MoRe® 13%, 50%, respectively; Titanium 10%, 25%. Recoil: MoRe® <2%, Titanium 6%. Hardness Range: MoRe® 280-800HV, Titanium 350-400HV. Max Run-Out Load Bent Rod: MoRe® 4.0 mm rod 350 N, Titanium 5.5 mm rod 150 N. Decrease in Max Run-Out Load Bent, Unbent, Re-bent Rod: MoRe® -9%, Titanium -17%. Conclusion: The MoRe® alloy, with its advantageous mechanical properties, offers great promise for the design of a new generation of smaller, stronger and more fatigue resistant foot and ankle implants, resulting in less soft tissue disruption, quicker recovery and better outcomes for patients.

Smart Expandable Cement Additive to Achieve Better Wellbore Integrity

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
A. Dahi Taleghani ◽  
G. Li ◽  
M. Moayeri
Keyword(s):  
Mechanical Properties ◽  
Oil And Gas ◽  
Setting Time ◽  
Oil And Gas Industry ◽  
Test Methods ◽  
Standard Test ◽  
Cement Slurry ◽  
Gas Industry ◽  
Additive Particles ◽  
Cement Additive

One of the serious challenges encountered in cementing oil and gas wells is the failure of the cement sheaths and its debonding from casing or formation rock. Shrinkage of the cement during setting is identified as one of the driving factors behind these issues. Some expansive cement systems have been developed in the oil and gas industry to compensate for the shrinkage effect. All the expansive additives which have been developed so far have chemical reactions with the cement itself that would significantly impact the mechanical strength of the cement. In this paper, we present a new class of polymer-based expandable cement additive particles which are made of shape memory polymers (SMP). This class of polymers is designed to expand to the required extent when exposed to temperatures above 50–100 °C (122–212 °F) which is below the temperature of the cementing zone. It is notable that expansion occurs after placement of the cement but before its setting. The API RP 10 B-2 and 5 have been followed as standard test methods to evaluate expansion and strength of the cement slurry after utilizing the new additive. The proposed additive does not react with the water or cement content of the slurry. Mechanical evaluation tests confirm the potential benefit of this additive without any deteriorative effect on mechanical properties or setting time of the cement paste and significant impact on its mechanical properties. Hence, this additive would provide a reliable way to prevent cement channeling, debonding, and fluid migration to upper formations.

Fracture Toughness Determined From Full-Scale Pipe

2012 ◽  
Author(s):  
A-H. I. Mourad ◽  
J. Altarawneh ◽  
A. El Domiaty ◽  
Y. J. Chao
Keyword(s):  
Fracture Toughness ◽  
Plane Strain ◽  
Pipeline Steel ◽  
Tensile Load ◽  
Test Methods ◽  
Standard Test ◽  
Full Scale ◽  
Steel Plates ◽  
Plane Strain Condition ◽  
Strain Condition

Fracture toughness for full scale steel pipe of API 5L grade X65 PSL1 (ASTM A694F65) medium strength grade pipeline steel has been measured by a new test specimen utilizing the same procedure of the standard test methods ASTM E 399-90 and E 1820-01. Full scale pipe with circumferentially machined notch is pulled axially by tensile load up to fracture. An external circumferential sharp notch has been machined in the wall of the pipe to simulate the crack. To insure a plane strain condition around the crack a well lubricated and axially free loaded plug has been mounted, symmetrically around the circumferential notch, inside the pipe. Evidences of cleavage fracture have been observed on the fracture surface. The measured value of the fracture toughness has been found to be very close to the values measured according to the standard test for steel plates of similar grade. The new proposed testing method for full scale pipe can be used regardless its dimensions since it appears to provide plane strain condition around the crack.

scholarly journals General Considerations on Antimicrobial Tests and Conditions Applicable in Textile Industry

2019 ◽  
pp. 1-8
Author(s):  
Ali Mohamed Elshafei
Keyword(s):  
Textile Industry ◽  
Antimicrobial Properties ◽  
Test Methods ◽  
Standard Test ◽  
Standard Methods ◽  
Sterility Test ◽  
Antimicrobial Test ◽  
Antimicrobial Materials ◽  
Scientific Principles ◽  
The Difference

Due to the globally increasing need for utilizing antimicrobial materials, it is necessary to improve and develop newer methods and techniques for determining the antimicrobial properties of these materials qualitatively and quantitatively, especially in the medical field. Recently there has been a debate among scientists between the difference between antimicrobial test and sterility test. For antimicrobial and microbial resistance, the test is limited to the standard methods to determine the effect of the sample as an antimicrobial without paying attention to the fact that the sample is sterile or not, unless the sample was taken into sterile atmosphere and isolated with a protective suitable sterile package cover after treatment with the antimicrobial agent because the external    atmosphere contains a lot of scattered types of bacterial and fungal microorganisms. In case of sterility test, the sample to be examined should be prepared, isolated and coated from the outside atmosphere, where the presence of microbes on the surface of the sample by standard methods is detected and in some sterilization tests it is prohibited to include an antimicrobial substance to the sample to be tested to avoid the interference with the test. In both cases the tests should be implemented in a sterilized room and conditions according to the recognized scientific principles. In conclusions, the antimicrobial test is used to make sure that the specimen is attained antimicrobial properties or not and the sterilization test is done by ensuring that the sample is free of contaminated microorganisms. This review poses on some factor and conditions affecting antimicrobial action and some standard test methods for determination of antimicrobial and sterility potential of materials.

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