The Role of Strength in Determining Composite Material Toughness Using the Interface Indentation Fracture Test

2012 ◽  
Author(s):  
Brian A. Grimm ◽  
John P. Parmigiani
Keyword(s):  
Fracture Toughness ◽  
Cohesive Zone ◽  
Measurement Techniques ◽  
Element Model ◽  
Interface Strength ◽  
Test Method ◽  
Interface Fracture ◽  
Indentation Fracture ◽  
Zone Method ◽  
Brittle Composite

Understanding fracture behavior at the interfaces of brittle composite materials requires appropriate measurement techniques for fracture toughness. Due to their simplicity and convenience, indentation techniques are attractive solutions. One such technique is the interface indentation fracture (IIF) test, which measures the relative toughness of interfaces between brittle materials by introducing a series of indents at various angles of incidence (0–90°) to the interface, from which crack growth will either be by penetration through the interface or by deflection (debonding) along it. Larger angles of incidence promote penetration and smaller angles promote deflection, so by noting the critical angle at which propagation changes from penetration to deflection, the IFF test can make inferences about relative fracture toughness of different interfaces tested under similar conditions. However, as previous work by Parmigiani and Thouless has shown, the penetration vs. deflection behavior of a crack incident to an interface is a function not only of interface fracture toughness but also of interface strength. Interface cohesive zone elements in a finite element model incorporating both fracture toughness and strength criteria were used to study the propagation behavior of cracks normally incident to brittle composite interfaces. In the follow up work presented here, the cohesive zone method (CZM) has been extended to study cracks that occur at varying angles of incidence to these interfaces. Results show that IIF testing does not always result in unique values for relative fracture toughness; when interface strength is varied, it is possible for identical IIF-test critical angles to correspond to differing interface toughness values and, conversely, for differing critical angles to correspond to identical fracture toughness values. To properly employ the IFF test method, this phenomenon must be taken into account.

Damage initiation and fracture analysis of honeycomb core single cantilever beam sandwich specimens

2020 ◽  
pp. 109963622090982 ◽  
Author(s):  
Vishnu Saseendran ◽  
Pirashandan Varatharaj ◽  
Shenal Perera ◽  
Waruna Seneviratne
Keyword(s):  
Cantilever Beam ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Element Model ◽  
Interface Fracture ◽  
Zone Model ◽  
Honeycomb Core ◽  
Damage Initiation ◽  
Foundation Model ◽  
Honeycomb Cell

Fracture testing and analysis of aerospace grade honeycomb core sandwich constructions using a single cantilever beam test methodology is presented here. Influence of various parameters such as facesheet thickness, core density, honeycomb cell-size, and core thickness were studied. A Winkler-based foundation model was used to calculate compliance and energy-release rate, and further compare with finite element model and experiments. A cohesive zone model was developed to predict the disbond initiation and simulate the interface crack propagation in the single cantilever beam sandwich specimen. The mode I interface fracture toughness obtained from the translating base single cantilever beam setup was provided as input in this cohesive zone model. It is shown that the presented cohesive zone approach is robust, and is able to capture the debonding phenomenon for majority of the honeycomb core specimens.

Study on Model of Meso-Scale Simulation for Aircraft Structure Material Based on Voronoi Algorithm

2014 ◽  
Vol 1065-1069 ◽  
pp. 2086-2089
Author(s):  
Kai Zhou ◽  
Hai Dong Wang ◽  
Gui Xue Bian ◽  
Zhan Yong Wang ◽  
Shi Lu Zhang
Keyword(s):  
Fatigue Crack ◽  
Cohesive Zone ◽  
Polycrystalline Material ◽  
Element Model ◽  
Aircraft Structure ◽  
Zone Method ◽  
Scale Theory ◽  
Multi Scale ◽  
The Finite Element Model ◽  
Meso Scale

Multi-scale theory and framework in research of fatigue crack is described, and then in meso-scale the simulation model of polycrystalline material grains is established using Voronoi algorithm, and the feasibility of this algorithm is verified at the same time; cohesive zone method is introduced and cohesive strength on the interface along grain boundaries is discussed, then Young´s modulus is tried to define in meso-scale according to cohesive zone method, which prepares the calculation of the finite element model.

A New Approach for Bimaterial Interface Fracture Toughness Evaluation

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
John Jy-An Wang ◽  
Ian G. Wright ◽  
Michael J. Lance ◽  
Ken C. Liu
Keyword(s):  
Thin Film ◽  
Fracture Toughness ◽  
Lattice Mismatch ◽  
Coefficient Of Thermal Expansion ◽  
Test Method ◽  
Interface Fracture ◽  
Bimaterial Interface ◽  
Material Interfaces ◽  
Coating Materials ◽  
Interface Fracture Toughness

A material configuration of central importance in composite materials or in protective coating technology is a thin film of one material deposited onto a substrate of a different material. Fabrication of such a structure inevitably gives rise to stress in the film due to lattice mismatch, differing coefficient of thermal expansion, chemical reactions, or other physical effects. Therefore, in general, the weakest link in this composite system often resides at the interface between the thin film and the substrate. In order to make multilayered electronic devices and structural composites with long-term reliability, the fracture behavior of the material interfaces must be known. This project offers an innovative testing procedure of using a spiral notch torsion bar method for the determination of interface fracture toughness that is applicable to thin coating materials in general. The feasibility study indicated that this approach for studying thin film interface fracture is repeatable and reliable, and the demonstrated test method closely adheres to and is consistent with classical fracture mechanics theory.

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.

Coating Interface Fracture Toughness Evaluation by a Combination of Edge Compression and Slinging Load

2004 ◽  
Vol 261-263 ◽  
pp. 435-440 ◽  
Author(s):  
Masayuki Arai ◽  
Yoshifumi Okajima ◽  
Kikuo Kishimoto
Keyword(s):  
Fracture Toughness ◽  
Phase Angle ◽  
Complex Stress ◽  
Test Method ◽  
Interface Fracture ◽  
Beam Model ◽  
Fracture Toughness Test ◽  
Barrier Coating ◽  
Interface Fracture Toughness ◽  
Toughness Evaluation

Previous methods to measure interface fracture toughness between coating and substrate can't easily vary a phase angle as a mixed mode parameter. So that, the new coating interface fracture toughness test method, by which phase angle at interface crack tip can be varied due to applying a combination of compression loading to the coating edge and slinging such as beam bending, is proposed. The simple formula, which connects to complex stress intensity factors and double loading is firstly derived on the basis of the cracked beam model proposed by Suo and Hutchinson [1]. As an application of the method and associated formula, thermal barrier coating/super-alloy interface toughness is evaluated based on numerical analysis.

Determination of Interface Fracture Toughness in Thermal Barrier Coating System by Blister Tests

2003 ◽  
Vol 125 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Y. C. Zhou ◽  
T. Hashida ◽  
C. Y. Jian
Keyword(s):  
Fracture Toughness ◽  
Phase Angle ◽  
Main Crack ◽  
Interfacial Crack ◽  
Type A ◽  
Test Method ◽  
Interface Fracture ◽  
Stable Phase ◽  
Type B ◽  
Interface Fracture Toughness

The theoretical model for the blister test method was used to analyze the interface fracture toughness of zirconia coating deposited on an SUS304 stainless steel substrate by a plasma-spraying method. The elastic parameters of the debonded coating were determined by testing the oil pressure q and maximum deflection w(0). SEM observation, compliance method and ultrasonic detection were used to determine the radius of the debonded coating. The three methods gave the same results for the debonded coating radius. Micro-observations showed that the interfacial crack propagates by the growth of voids or microcracks ahead of the main crack and coalescence with the main crack. The energy release rate G0 with phase angle ψ=0 for type A coating and type B coating was, respectively, 14.54∼25.88J/m2 and 11.88∼16.21J/m2. The corresponding interface fracture toughness for type A TBC coating and for type B TBC coating is, respectively, 0.77∼1.02MPas˙m1/2 and 0.52∼0.61MPas˙m1/2. The stable phase angle was approximately −31.5° and −30.2° for coating A and coating B, respectively.

Interface Strength Between Sub-Micron Thin Films in Opening and Sliding Delamination Modes

2002 ◽  
Author(s):  
Tadahiro Shibutani ◽  
Tetsu Tsuruga ◽  
Qiang Yu ◽  
Masaki Shiratori
Keyword(s):  
Thin Films ◽  
Fracture Toughness ◽  
Evaluation Method ◽  
Sliding Mode ◽  
Stress Singularity ◽  
Interface Strength ◽  
Interface Fracture ◽  
Interface Toughness ◽  
Interface Fracture Toughness ◽  
Opening Mode

Delamination between thin films is classified into two types: opening mode and sliding mode. Corresponding to each mode, there is the interface strength between thin films. This paper aims to evaluate interface strength between the sub-micron thin films for opening mode and sliding mode, respectively. We already developed the evaluation method of interface fracture toughness for opening mode on the basis of fracture mechanics concept elsewhere. Moreover, the evaluation method of sliding mode is proposed and the interface strength between thin films for an advanced LSI is evaluated as the fracture toughness by using both methods. In both modes, the stress singularity appears in the vicinity of the edge of interface and governs the delamination. The criterion of crack initiation for each mode is evaluated as the interface toughness. The fracture toughness at the edge of interface in sliding mode is lower than that in opening mode.

scholarly journals Test method for fracture toughness of monolithic ceramics by indentation fracture (IF) method

Synthesiology ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 29-44
Author(s):  
Hiroyuki MIYAZAKI ◽  
Kouichi YASUDA ◽  
Yu-ichi YOSHIZAWA
Keyword(s):  
Fracture Toughness ◽  
Test Method ◽  
Indentation Fracture ◽  
Monolithic Ceramics
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