Spiral Notch Torsion Test Use for Determining Fracture Toughness of Structural Materials

2012 ◽  
Author(s):  
Jy-An John Wang ◽  
Fei Ren ◽  
Ting Tan
Keyword(s):  
Fracture Toughness ◽  
Three Dimensional ◽  
Torsion Test ◽  
Computer Code ◽  
Structural Materials ◽  
Fracture Toughness Test ◽  
Materials Used ◽  
Torsion Fracture ◽  
Three Dimensional Finite Element ◽  
Spiral Notch

Spiral Notch Torsion Fracture Toughness Test (SNTT) was developed recently to measure 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. The KIC values are obtained with the aid of a 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, including others such as ceramics, their composites, graphite, concrete, and polymeric composites. The SNTT test results for some of these structural materials are demonstrated in this paper.

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.

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.

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

2004 ◽  
Vol 126 (4) ◽  
pp. 534-540 ◽  
Author(s):  
J. A. Wang ◽  
K. C. Liu
Keyword(s):  
Fracture Toughness ◽  
National Laboratory ◽  
Three Dimensional ◽  
Torsion Test ◽  
Computer Code ◽  
Structural Materials ◽  
Oak Ridge ◽  
Dimensional Finite Element ◽  
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 deg pitch. The KIC values are obtained with the aid of a three-dimensional finite-element computer code, TOR3D-KIC, developed at Oak Ridge National Laboratory (ORNL). The fundamental mechanism of SNTT approach is also described in the paper.

A Three-Dimensional Finite Element Analysis of the Double-Torsion Test

1979 ◽  
Vol 101 (4) ◽  
pp. 328-335 ◽  
Author(s):  
A. A. Tseng ◽  
J. T. Berry
Keyword(s):  
Fracture Toughness ◽  
Finite Element ◽  
Crack Length ◽  
Three Dimensional ◽  
Torsion Test ◽  
Test Method ◽  
Fracture Toughness Test ◽  
Element Analysis ◽  
Three Dimensional Finite Element ◽  
Double Torsion

A special three-dimensional crack-tip element has been developed to investigate a simple and widely applicable fracture toughness test method. Previous experimental work with the double-torsion method has shown that the use of a relatively thin sectioned specimen may be permitted. The section concerned is considerably thinner than that used in conventional techniques, while the technique also simplifies the determination of the fracture toughness parameter. K IC values, which are independent of the crack length, have been obtained for glasses, ceramics, polymers, and a variety of metals and alloys. The numerical solution presented is supportive of many experimental observations made during testing. Excellent correlation between the finite element and experimental results has been obtained. The maximum stress intensity factor is shown to be almost independent of crack length over a considerable range.

Prediction of Failure Behavior for Nuclear Piping Using Curved Wide-Plate Test

2004 ◽  
Vol 126 (4) ◽  
pp. 419-425 ◽  
Author(s):  
Nam-Su Huh ◽  
Yun-Jae Kim ◽  
Jae-Boong Choi ◽  
Young-Jin Kim ◽  
Chang-Ryul Pyo
Keyword(s):  
Fracture Toughness ◽  
Three Dimensional ◽  
Crack Tip ◽  
Full Scale ◽  
Failure Behavior ◽  
Resistance Curve ◽  
Testing Specimen ◽  
Plate Test ◽  
Crack Tip Constraint ◽  
Three Dimensional Finite Element

One important element of the Leak-Before-Break analysis of nuclear piping is how to determine relevant fracture toughness (or the J-resistance curve) for nonlinear fracture mechanics analysis. The practice to use fracture toughness from a standard C(T) specimen is known to often give conservative estimates of toughness. To improve the accuracy of predicting piping failure, this paper proposes a new method to determine fracture toughness using a nonstandard testing specimen, curved wide-plate in tension. To show validity of the proposed curved wide-plate test, the J-resistance curve from the full-scale pipe test is compared with that from the curved wide-plate test and that from C(T) specimen. It is shown that the J-resistance curve from the curved wide-plate tension test is similar to, but that from the C(T) specimen is lower than, the J-resistance curve from the full-scale pipe test. Further validation is performed by investigating crack-tip constraint conditions via detailed three-dimensional finite element analyses, which shows that the crack-tip constraint condition in the curved wide-plate tension specimen is indeed similar to that in the full-scale pipe under bending.

Optimization of Adhesively Bonded Spar-Wingskin Joints of Laminated FRP Composites Subjected to Pull-Off Load: A Critical Review

2020 ◽  
Vol 8 (1) ◽  
pp. 29-46
Author(s):  
S. Rakshe ◽  
S. V. Nimje ◽  
S. K. Panigrahi
Keyword(s):  
Three Dimensional ◽  
Von Mises Stress ◽  
Geometrical Parameters ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Frp Composites ◽  
Dimensional Finite Element ◽  
Materials Used ◽  
Von Mises ◽  
Three Dimensional Finite Element

A review on optimization of adhesively bonded spar-wingskin joint (SWJ) of laminated fiber reinforced polymer (FRP) composites subjected to pull-off load is presented in this article using three-dimensional finite element analysis. Von Mises stress components have been computed across the width of joint at different interfaces viz. load coupler-spar, and load coupler-wingskin interfaces. Further, the weight of SWJ structure is considered as the objective function which needs to be minimized for optimization. In the first step, the material and lamination scheme of the FRP composite materials used for SWJ are optimized, and, in the second step, the geometrical parameters have been optimized on the basis of minimum von Mises stress and weight. Further, the effects of the material, lamination scheme, and geometrical parameters on the von Mises stress and weight have been validated using the Analysis of Variance (ANOVA) approach as prescribed by the Taguchi method. The results show that the material and spar thickness are the most significant factors influencing von Mises stress. The weight analysis reveals that there is a significant effect of change in material and wingskin thickness on SWJ performance. Suitable design recommendations have been made for SWJ in terms of material, lamination scheme and geometrical parameters.

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