scholarly journals Temperature Dependence of the Fracture Toughness JC of Random Fibrous Material

2020 ◽  
Vol 10 (3) ◽  
pp. 941
Author(s):  
Datao Li ◽  
Yan Li ◽  
Wenshan Yu
Keyword(s):  
Fracture Toughness ◽  
Temperature Dependence ◽  
Fracture Strength ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Compact Tension ◽  
Fe Model ◽  
The Finite Element Method ◽  
Silica Fibers ◽  
Different Temperatures

The temperature dependence of the fracture toughness JC of a three-dimensional (3D) random fibrous (RF) material, with a porosity of 87% along the through-the-thickness (TTT) direction, was investigated using experiments and the finite element method (FEM) in this study. The temperature considered ranges from 299 to 1273 K. The experimental observations revealed the fracture toughness JC with crack length-to-width ratios of 0.4 and 0.5, which increased from 47.32 to 328.28 J/m2 and from 44.92 to 280.09 J/m2, respectively, as the temperature increased. Then, a 3D FE model, considering the meso-morphology characteristics of the 3D RF material, was developed to simulate a size-scaled compact tension (CT) specimen with a single edge crack. Using the elastic modulus and the fracture strength of the silica fibers at room temperature, we verified the effectiveness of the FE model, then predicted the fracture strength of the silica fibers and the bonding between the fibers at elevated temperatures. In addition, our developed FE model proved to successfully simulate the fracture toughness JC from 299 to 1273 K and reveal the deformation mechanism of the 3D RF material at different temperatures.

Mechanical Property and Oxidation Behavior of LPS-SiC Materials

2006 ◽  
Vol 321-323 ◽  
pp. 913-916
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Jong Baek Lee ◽  
Jun Young Park
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Indentation Test ◽  
Bending Test ◽  
Secondary Phases ◽  
Three Point Bending ◽  
Different Temperatures

The microstructure and the mechanical property of liquid phase sintered (LPS) SiC materials with oxide secondary phases have been investigated. The strength variation of LPS-SiC materials exposed at the elevated temperatures has been also examined. LPS-SiC materials were sintered at the different temperatures using two types of Al2O3/Y2O3 compositional ratio. The characterization of LPS-SiC materials was investigated by means of SEM with EDS, three point bending test and indentation test. The LPS-SiC material with a density of about 3.2 Mg/m3 represented a flexural strength of about 800 MPa and a fracture toughness of about 9.0 MPa⋅√m.

C-Specimen Fracture Toughness Testing: Effect of Side Grooves and η Factor

2003 ◽  
Author(s):  
Y. Kim ◽  
Y. J. Chao ◽  
M. J. Pechersky ◽  
M. J. Morgan
Keyword(s):  
Fracture Toughness ◽  
Plane Strain ◽  
Crack Front ◽  
Testing Effect ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
J Integral ◽  
Η Factor

Elastic-plastic crack front fields in arc-shaped tension specimens (C-specimens) were analyzed by a three-dimensional finite element method. The effect of side grooves on the ductile fracture behavior was investigated by studying the J-integral distribution, plane-strain constraint parameter, and development of plastic zones and comparing to experimental data. The applicability of the η factor (derived for use with compact tension specimens) for the calculation of J-integral values for the C-specimen was also investigated. The results show that side grooves promote and establish near plane strain conditions at the crack front in sub-size specimens. It was also found that a two-dimensional plane-strain analysis in conjunction with the standard American Society for Testing and Materials (ASTM) tests was sufficient to determine the fracture toughness values from side-grooved C-specimen. The results indicate the η factor for compact tension specimen as specified in the ASTM standards appears to produce reliable results for the calculation of J of C-specimens.

C-Specimen Fracture Toughness Testing: Effect of Side Grooves and η Factor

2004 ◽  
Vol 126 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Y. Kim ◽  
Y. J. Chao ◽  
M. J. Pechersky ◽  
M. J. Morgan
Keyword(s):  
Fracture Toughness ◽  
Plane Strain ◽  
Crack Front ◽  
Testing Effect ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
J Integral ◽  
Η Factor

Elastic-plastic crack front fields in arc-shaped tension specimens (C-specimens) were analyzed by a three-dimensional finite element method. The effect of side grooves on the ductile fracture behavior was investigated by studying the J-integral distribution, plane-strain constraint parameter, and development of plastic zones and comparing to experimental data. The applicability of the η factor (derived for use with compact tension specimens) for the calculation of J-integral values for the C-specimen was also investigated. The results show that side grooves promote and establish near plane strain conditions at the crack front in sub-size specimens. It was also found that a two-dimensional plane-strain analysis in conjunction with the standard American Society for Testing and Materials (ASTM) tests was sufficient to determine the fracture toughness values from side-grooved C-specimen. The results indicate the η factor for compact tension specimen as specified in the ASTM standards appears to produce reliable results for the calculation of J of C-specimens.

Effect of Various Side Grooves on 3D Crack-Front J-Integral for CT Specimens

2016 ◽  
Vol 853 ◽  
pp. 46-50 ◽  
Author(s):  
Xiang Qing Li ◽  
Chuan Xiao Wu ◽  
Jian Feng Mao ◽  
Shi Yi Bao ◽  
Zeng Liang Gao
Keyword(s):  
Fracture Toughness ◽  
Crack Front ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Compact Tension ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Strain Relationship

Three-dimensional (3D) elastic-plastic finite element model (FEM) is adopted to research the effect of side groove on the crack-front J-integral for different size of Compact Tension (CT) specimens. Although the side-grooved CT specimen is widely used in the existing test method, such as ASTM E1820-13, the test data of fracture toughness is varying with the various geometric parameters. Before FE calculation, the material properties of Q345 steel were obtained by uniaxial tensile test, especially for the true stress-strain relationship. In this paper, it focuses on the numerical study of geometric parameter effects on the fracture toughness. Toward this end, the commercial FE software of ABAQUS is adopted to calculate the J-integral. Since the side groove of CT specimen is so important to make the fracture test success, the various parameters of side groove is intensively analyzed for obtaining the accurate J-integral along the crack front, including the effects of the angle, depth and root radius. In fact, the side groove effect is so significant around the crack front that cannot be ignored in the J-integral calculation. Through rigorous FE investigation, the influence of the side groove on the fracture toughness testing is fully disclosed, and the appropriate side groove configuration is recommended accordingly.

Effect of Annealing on Fracture Toughness Evaluation of Ba0.5Sr0.5Co0.8 Fe0.2O3−δ (BSCF) at Different Temperatures

2014 ◽  
Vol 592-594 ◽  
pp. 816-820 ◽  
Author(s):  
Bablu Sikder ◽  
Abhijit Chanda
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Fracture Stress ◽  
Compressive Residual Stress ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Toughness Evaluation ◽  
Different Temperatures ◽  
Fracture Toughness Evaluation ◽  
Typical Variation

An experimental study on the fracture toughness of BSCF samples were conducted at room temperature as well as elevated temperatures (upto 800°C). The results showed a typical variation of fracture toughness and fracture stress with temperature. It decreased upto 600°C and then increased to reach a comparatively higher value at 800°C. Without annealing the samples showed comparatively higher fracture toughness because of the presence of compressive residual stress.

Mixed Mode Failure Criterion for Random Composites Using a Finite Element Model

2016 ◽  
Vol 713 ◽  
pp. 90-93 ◽  
Author(s):  
J. Jamali ◽  
P. Sharifi ◽  
M.J. Mahmoodi ◽  
A.H.I. Mourad ◽  
J.T. Wood
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Strain Energy Release ◽  
Element Model ◽  
Compact Tension ◽  
Mixed Mode Fracture ◽  
Fe Model ◽  
Pull Out ◽  
Random Composites ◽  
Mode Failure

In this research mixed-mode fracture behaviour of glass fibre/epoxy composite with randomly distributed glass fibres investigated. Various modes of loading were applied. Compact tension shear (CTS) fixture with different loading angles were used. The testing is used to measure the fracture toughness. Critical strain energy release rate (CSERR) of the composite was then calculated using the measured fracture toughness. A model is proposed to predict the value of CSERR based on the constituents and interfacial properties. Different failure mechanisms are considered in developing a criterion. To derive the criterion a FE model is used to determine the amount of energy released during the fibre pull out which is major part of energy dissipation.

scholarly journals Modeling Laterally Loaded Single Piles Accounting for Nonlinear Soil-Pile Interactions

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Maryam Mardfekri ◽  
Paolo Gardoni ◽  
Jose M. Roesset
Keyword(s):  
Finite Element ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Soil Mass ◽  
Fe Model ◽  
The Finite Element Method ◽  
Pile Diameter ◽  
Single Piles ◽  
Laterally Loaded

The nonlinear behavior of a laterally loaded monopile foundation is studied using the finite element method (FEM) to account for soil-pile interactions. Three-dimensional (3D) finite element modeling is a convenient and reliable approach to account for the continuity of the soil mass and the nonlinearity of the soil-pile interactions. Existing simple methods for predicting the deflection of laterally loaded single piles in sand and clay (e.g., beam on elastic foundation,p-ymethod, and SALLOP) are assessed using linear and nonlinear finite element analyses. The results indicate that for the specific case considered here thep-ymethod provides a reasonable accuracy, in spite of its simplicity, in predicting the lateral deflection of single piles. A simplified linear finite element (FE) analysis of piles, often used in the literature, is also investigated and the influence of accounting for the pile diameter in the simplified linear FE model is evaluated. It is shown that modeling the pile as a line with beam-column elements results in a reduced contribution of the surrounding soil to the lateral stiffness of the pile and an increase of up to 200% in the predicted maximum lateral displacement of the pile head.

Mechanistic Aspects of Fracture of Human Cortical Bone

2004 ◽  
Vol 823 ◽  
Author(s):  
Ravi K. Nalla ◽  
Jamie J. Kruzic ◽  
John H. Kinney ◽  
R. O. Ritchie
Keyword(s):  
Fracture Toughness ◽  
Cortical Bone ◽  
Crack Extension ◽  
Three Dimensional ◽  
Compact Tension ◽  
Initiation Toughness ◽  
Post Test ◽  
X Ray Computed ◽  
Distal Direction

AbstractThere has been growing interest of late in the fracture properties of human bone. As understanding such properties in the context of the hierarchical microstructure of bone is of obvious importance, this study addresses the evolution of the in vitro fracture toughness with crack extension (Resistance-curve behavior) in terms of the salient mechanisms involved. Fracture-mechanics based measurements were performed on compact-tension specimens hydrated in Hanks' Balanced Salt Solution using cortical bone from mid-diaphyses of 34-41 year-old human humeri. Post-test observations of the crack path were made by optical microscopy and three-dimensional X-ray computed tomography. The fracture toughness was found to rise linearly with crack extension with a mean crack-initiation toughness of Ko ∼ 2.0 MPa√m for crack growth in the proximal-distal direction. The increasing cracking resistance had its origins in several toughening mechanisms, most notably crack bridging by uncracked ligaments. Uncracked-ligament bridging, which was observed by tomography in the wake of the crack, was identified as the dominant toughening mechanism responsible for the observed Rcurve behavior through compliance-based experiments. The extent and nature of the bridging zone was examined quantitatively using multi-cutting compliance experiments in order to assess the bridging stress distribution. The results obtained in this study provide an improved understanding of the mechanisms associated with the failure of cortical bone, and as such are of importance from the perspective of developing a realistic framework for fracture risk assessment, and for determining how the increasing propensity for fracture with age can be prevented.

Sign in / Sign up

Export Citation Format

Share Document