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.

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 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 Comparison of Two Intergranular Corrosion Tests on EN AW-6016 Sheet Material

2021 ◽  
Vol 11 (11) ◽  
pp. 5294
Author(s):  
Peer Decker ◽  
Ines Zerbin ◽  
Luisa Marzoli ◽  
Marcel Rosefort
Keyword(s):  
Optical Microscopy ◽  
Intergranular Corrosion ◽  
Sheet Material ◽  
Test Methods ◽  
Standard Test ◽  
Corrosion Depth ◽  
Corrosion Tests ◽  
Automotive Company ◽  
Test Parameters

Two different intergranular corrosion tests were performed on EN AW-6016 sheet material, an ISO 11846:1995-based test with varying solution amounts and acid concentrations, and a standard test of an automotive company (PV1113, VW-Audi). The average intergranular corrosion depth was determined via optical microscopy. The differences in the intergranular corrosion depths were then discussed with regard to the applicability and quality of the two different test methods. The influence of varying test parameters for ISO 11846:1995 was discussed as well. The determined IGC depths were found to be strongly dependent on the testing parameters, which will therefore have a pronounced influence on the determined IGC susceptibility of a material. In general, ISO 11846:1995 tests resulted in a significantly lower corrosion speed, and the corrosive attack was found to be primarily along grain boundaries.

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