Determination of Stress Intensity Factors for an Interfacial Crack in a Bi-Material by Digital Photoelasticity

2004 ◽  
Vol 1-2 ◽  
pp. 139-146
Author(s):  
M. Ravichandran ◽  
K. Ramesh
Keyword(s):  
Stress Intensity ◽  
Stress Field ◽  
Stress Intensity Factors ◽  
Interfacial Crack ◽  
Intensity Factors ◽  
Singular Stress ◽  
Singular Stress Field ◽  
Digital Photoelasticity ◽  
Least Squares Approach

The main sources of error in the determination of stress intensity factors (SIFs) for an interface crack in a bi-material by conventional photoelasticity are the measurement of the positional co-ordinates of the data point and the fringe order. In the present work, use of two digital photoelasticity methods for collecting these data is discussed. SIFs are evaluated using constant radius method and a least squares approach based on the singular stress field equation. The need for developing a multi-parameter stress field solution for evaluating SIF is highlighted.

Use of automated photoelasticity to determine stress intensity factors of bimaterial joints

2005 ◽  
Vol 40 (8) ◽  
pp. 785-800 ◽  
Author(s):  
B Zuccarello ◽  
S Ferrante
Keyword(s):  
Stress Intensity ◽  
Stress Field ◽  
Stress Intensity Factors ◽  
External Loading ◽  
Intensity Factors ◽  
Singular Stress ◽  
Full Field ◽  
Basic Law ◽  
Singular Stress Field ◽  
Element Approach

A new systematic experimental procedure has been developed to obtain the stress intensity factors governing the singular stress field that occurs near the intersection between the interface and free edges of bimaterial joints. A preliminary theoretical study of the singular stress field is carried out by the well-known Airy stress function method. The obtained stress laws are properly combined with the basic law of photoelasticity in order to define a procedure that permits the zone dominated by the singularity to be located and the stress intensity factors (SIFs) to be computed on the basis of full field data provided from automated photoelasticity. In particular, a systematic error analysis is used to determine the model zone where the experimental data have to be collected in order to obtain accurate SIF evaluation. As an example, the proposed method is applied to determine the SIFs of various aluminium/ PSM-1 specimens under different external loading conditions using Fourier transform photoelasticity. The experimental results have been compared to those obtained by an independent procedure, based on a boundary element approach, in order to validate the accuracy of the proposed procedure.

Effects of the Length of Carbon Nanotube (CNT) in CNT Reinforced Composites

2006 ◽  
Vol 324-325 ◽  
pp. 855-858
Author(s):  
Q. Wang ◽  
X. F. Sun ◽  
Kimihiro Ozaki
Keyword(s):  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Stress Intensity ◽  
Stress Field ◽  
Stress Intensity Factors ◽  
Reinforced Composites ◽  
Intensity Factors ◽  
Singular Stress ◽  
Singular Stress Field

In this paper, the strength of the singular stress field near the ends of the CNTs in composites was analyzed to clarify the effects of the CNT length on stress filed in the CNT reinforced composites when studying the fracture toughness. The singular stress field was separated into two types of singularities, symmetric and skew-symmetric, near the ends of CNTs according to the deformation and loading types. The stress intensity factors of the singular stress field were calculated for these two types of singularities. The effects of the CNT length in CNT reinforced composites on these stress intensity factors were investigated.

An improved boundary element formulation for calculating stress intensity factors: Application to aerospace structures

1987 ◽  
Vol 22 (4) ◽  
pp. 203-207 ◽  
Author(s):  
M H Aliabadi ◽  
D P Rooke ◽  
D J Cartwright
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Boundary Element ◽  
Stress Intensity Factors ◽  
Crack Tip ◽  
Stress Fields ◽  
Element Formulation ◽  
Intensity Factors ◽  
Singular Stress ◽  
Singular Stress Field

In order to compute stress intensity factors accurately, the standard boundary element method is modified to take explicit account of the singularity in the stresses at a crack-tip. The known expansion terms of the crack tip displacement and stress fields are subtracted to remove the numerical difficulties associated with the representation of a singular stress field at the crack-tip. Hence the accuracy of calculation is much improved, without appreciably increasing the amount of computation involved. Furthermore, the stress intensity factor is directly obtained as a part of a solution and no extrapolations are required. The improved formulation is applied to a configuration, which is representative of a part of the wing in a civil transport aeroplane. This configuration consists of a pair of circular cut-outs (supply ports) near to which smaller holes exist; these small holes are particularly susceptible to cracking.

scholarly journals Determination of stress intensity factors for elements with sharp corner located on the interface of a bi-material structure or homogeneous material

2020 ◽  
Author(s):  
Grzegorz Mieczkowski
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Direct Determination ◽  
Analytical Function ◽  
Material Structure ◽  
Homogeneous Material ◽  
Sharp Corner ◽  
Intensity Factors ◽  
Singular Stress

AbstractThis paper presents a new universal analytical and numerical method allowing for determination of stress intensity factors (SIFs) for notches and cracks located in both a homogeneous and a heterogeneous material. An advantage of the proposed method is that it does not require knowledge of an analytical description of singular stress/displacement fields or connection of SIFs to energy parameters such as energy release factor. In this method, a universal analytical function has been used, which in combination with data obtained using finite element method (FEM) allows for a direct determination of stress intensity factors. One parameter that is necessary to know when using the proposed method is the eigenvalue $$\lambda $$ λ . The characteristic equation allowing for determination of the eigenvalues for any corner has been given herein. What is more, also a criterion clearly defining the nodes is determined, from which FEM numerical results are implemented to the developed analytical function. In order to verify the proposed method, for a selected group of geometrical and material structures with sharp corner, values of stress intensity factors were determined and compared to data available in the literature. Satisfactory compliance of obtained results with literature ones was found.

DETERMINATION OF RESIDUAL STRESSES AND STRESS INTENSITY FACTORS BY REMOVING LOCAL MATERIAL

2017 ◽  
Vol 48 (4) ◽  
pp. 377-398
Author(s):  
Svyatoslav Igorevich Eleonskii ◽  
Igor Nikolaevich Odintsev ◽  
Vladimir Sergeevich Pisarev ◽  
Stanislav Mikhailovich Usov
Keyword(s):  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Local Material
Sign in / Sign up

Export Citation Format

Share Document