scholarly journals Test methods for measuring pure mode III delamination toughness of composite

2016 ◽  
Vol 55 ◽  
pp. 261-268 ◽  
Author(s):  
Yangyang Ge ◽  
Xiaojing Gong ◽  
Anita Hurez ◽  
Emmanuel De Luycker
Keyword(s):  
Test Methods ◽  
Pure Mode ◽  
Mode Iii ◽  
Delamination Toughness

The Contribution of Different Fracture Modes on Drilling Delamination Crack Propagation

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Mohammad Reza Vaziri Sereshk ◽  
Hamed Mohammadi Bidhendi
Keyword(s):  
Crack Propagation ◽  
Crack Nucleation ◽  
Dominant Mode ◽  
Mode I ◽  
Minor Effect ◽  
Pure Mode ◽  
Mode Iii ◽  
Major Mode ◽  
Drill Point ◽  
Drilling Conditions

Delamination as the main defect created during drilling of composite laminate is principally a crack nucleation and propagation phenomenon. The fracture-based investigation is performed to identify the significance of different modes involving in this process. The sensitivity analysis is implemented to evaluate magnitude and importance of each mode. As a result, mode I is a dominant mode while drill point removes the material; however, the crack continues to propagate under pure mode III for a while after drilling due to contact of flutes with spalls. This paper investigates the crack formation process for wide variety of drilling conditions and tool geometries. It is demonstrated that although mode III contributes, its minor effect might be neglected if comparing with fracture mode I. Therefore, it may be vanished as a tool design strategy. It is indicated that chisel edge plays a great role in crack propagation under major mode I; therefore, any further design approach which limits or eliminates opening action of chisel edge decreases delamination significantly. Material removal starting from hole perimeter as well as implementing small predrilled holes (such as action of primary cutting lips in step drill) are examined as solutions based on this approach.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Mixed Mode II/III Loading Conditions

2006 ◽  
Vol 129 (4) ◽  
pp. 664-669
Author(s):  
J. Pan ◽  
P.-C. Lin
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and nonsingular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson, and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

Finite Element Analysis of Secondary Cracks at a Crack Front under Pure Mode III Loading

2011 ◽  
Vol 488-489 ◽  
pp. 605-608 ◽  
Author(s):  
Matthias Ressel ◽  
Holger Theilig
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Front ◽  
Mechanical Analysis ◽  
Pure Mode ◽  
Fracture Criteria ◽  
Mode Iii ◽  
Element Analysis ◽  
Secondary Cracks ◽  
Loaded Crack

Several hypotheses and concepts exist for the prediction of crack deflection angles from the analysis of the undisturbed stress distribution at the crack front. In this paper, a finite element analysis of small penny shaped secondary cracks with deflection angles ψ0 = π/4 at a pure mode III loaded crack front is presented. The results are compared with the solutions of the well-known 3D fracture criteria. The fracture mechanical analysis is performed by the highly effective MVCCI-method.

A Model for a Propagating Shear Band on the Basis of a Tilt Wall Dislocation Array

1992 ◽  
Vol 45 (3S) ◽  
pp. S71-S74 ◽  
Author(s):  
J. P. Hirth
Keyword(s):  
Shear Band ◽  
Mixed Mode ◽  
Mode I ◽  
Pure Mode ◽  
Rotor Steel ◽  
Mode Iii ◽  
Microstructural Parameters ◽  
Plane Strain Tension ◽  
First Case ◽  
Propagating Shear

Microstructural parameters influencing shear band propagation and, ultimately, fracture in steels are reviewed for two types of test. These are the plane strain tension characteristics of spheroidized steels and the mixed mode I/III J-resistance behavior of a rotor steel. In the former case, shear band propagation is associated with voids forming at carbide particles because of incompatibility effects. In the latter case, the mixed mode I/III toughness is less than that in either pure mode I or pure mode III because local plastic flow in the path of the crack produces damage in the form of voids by a process analogous to the first case. A model for the interaction of a shear band and particles, suggested by these results, is proposed in the form of a discontinuous tilt wall of dislocations that breaks away and propagates past the particles. The model is shown to be consistent with several experimental observations, both of shear band characteristics and of the stress required to propagate the band.

Fracture Study on Mode I-III Crack of Rock

2006 ◽  
Vol 324-325 ◽  
pp. 1217-1220 ◽  
Author(s):  
Li Yun Li ◽  
Feng Guang Xu ◽  
He Ping Xie ◽  
Wei Ning
Keyword(s):  
Mixed Mode ◽  
Loading Condition ◽  
Fracture Propagation ◽  
Mode I ◽  
Pure Mode ◽  
Mode Iii ◽  
Element Analysis ◽  
Out Of Plane ◽  
Engineering Designs ◽  
Fracture Study

This paper illustrates some preliminary experimental, numerical and theoretical analysis results of mixed mode I-III rock cracks under apparent mode III loading. Some edge notched granite specimens are tested under out-of-plane four-points shearing loading condition, i.e., an apparent mode III loading condition. A series finite element analysis was conducted to understand the mechanism of the crack fracture propagation under this loading condition. The stress intensity factor distributions along the 3-D crack tips are also obtained. All crack fracture propagation surfaces of the specimens are similar helicoids which radius can be mainly influenced by the loading patterns, i.e., the action width s. The crack fracture initiates at the midpoint of the crack front. From the numerical calculation and experimental investigation, it has been revealed that all of these crack fracture initiations are caused by maxima tensile stress σ1. Based on this stress σ1, a new fracture criterion of mixed mode I-III is proposed. Its predictions agree well with the experiment results. This criterion can be applied to practice engineering designs which are related with mixed mode I-III or pure mode III rock crack fracture problems.

Mixed-Mode I/III Fracture Characterization of Aluminum Alloy

2013 ◽  
Vol 853 ◽  
pp. 187-191
Author(s):  
R. Ravichandaran ◽  
G. Thanigaiyarasu
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloy ◽  
Mixed Mode ◽  
Mode I ◽  
Pure Mode ◽  
Mode Iii ◽  
Fracture Characterization ◽  
Inclination Angles ◽  
Point Bend ◽  
Work Done

Aluminum alloy 5083 is taken for the study of fracture parameters in mixed-mode I/III. Three point bend specimens with load inclination and notch inclination are fabricated and precracked. They are tested with various inclination angles and for two different thicknesses. The results are analyzed and found that the fracture toughness decreases for larger inclination angles. Also, it is found that the thinner specimens are found to be tougher than the thicker specimens. Material and methods Symmetrical three-point bend cracked specimens have been used extensively in fracture mechanics to study mode I fracture properties because they are one of the standard types of specimens used in the ASTM codes for determining the fracture toughness JIc..In the mixed-mode I/III fracture, there is only a limited amount of experimental work done so far. The observations on combined mode I - mode III fracture have been very scarce and there is no general agreement among researchers on the effect of the addition of a mode III component to pure mode I loading. Limited study (Avci et al 2005 [, Kamat and Hirth 1996 [) has been done on bend specimens subjected to mixed-mode I/III when compared to the mode I case, i.e., a center-loaded specimen.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Combined In-Plane and Out-of-Plane Shear Loading Conditions

2005 ◽  
Author(s):  
J. Pan
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and non-singular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

Mode III Fracture Mechanics Analysis With Fourier Series Method

1991 ◽  
Vol 44 (11S) ◽  
pp. S166-S170 ◽  
Author(s):  
F. W. M. Kwok ◽  
L. C. Kang ◽  
C. R. Steele
Keyword(s):  
Fourier Series ◽  
Fracture Mechanics ◽  
Multiple Cracks ◽  
Pure Mode ◽  
Polygonal Domain ◽  
Series Method ◽  
Mode Iii ◽  
Fourier Series Method ◽  
Out Of Plane ◽  
Good Agreement

A numerical scheme based on the Fourier series method is developed for the solution of Laplace’s equation on a polygonal domain. This scheme is applied to the solution of the pure mode III fracture mechanics problem. For the single edge cracked strip problem under out-of-plane loading, the value of the J-Integral evaluated from the Fourier solution was found to be in good agreement with classical solution. The real power of the scheme lies in its applicability to general polygonal shapes. This capability is illustrated by three sample problems that involve strips with a slanted crack, multiple cracks and branching cracks under mode III loading.

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