Study on the Stress Intensity Factor of Double Cracks Parallel to and Lying on the Interface in the Cladding Material Structure

2011 ◽  
Vol 308-310 ◽  
pp. 224-227
Author(s):  
Jun Ru Yang ◽  
Gong Ling Chen ◽  
Li Li Zhang
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
Thickness Ratio ◽  
Material Structure ◽  
Crack Location ◽  
Finite Element Software ◽  
Cladding Material ◽  
Crack Space

Taking the cladding material structure with double interface cracks parallel to and lying on the interface as the study object, based on the theoretical study on the crack tip stress intensity factor(SIF), using the finite element software ANSYS, the SIFs are researched by changing the crack space, crack length, thickness ratio, load and crack location. The results show that, the crack SIFs increase firstly and then decrease with the crack space increase, increase with the increases of the crack length and the load, decrease a little with the thickness ratio increase, decrease firstly and then increase with the increase of distance between the crack and the boundary.

Study on the Stress Intensity Factors of Double Cracks Normal to and Dwelling on the Interface in the Cladding Material Structure

2012 ◽  
Vol 500 ◽  
pp. 525-530
Author(s):  
Jun Ru Yang ◽  
Gong Ling Chen ◽  
Li Li Zhang ◽  
Jing Sun
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Theoretical Study ◽  
Thickness Ratio ◽  
Crack Spacing ◽  
Material Structure ◽  
Intensity Factors ◽  
Crack Location ◽  
Finite Element Software ◽  
Cladding Material

Based on the theoretical study on the tip stress intensity factor (SIF) of the crack normal to and dwelling on the interface, using the finite element software ANSYS, the SIFs of the double interface cracks normal to and dwelling on the interface in cladding material structure are studied by changing the crack spacing, the crack length, the cladding thickness ratio, the load and the crack location. The results show that, the crack SIFs become larger with the increase of the crack spacing, the crack length and the load, they become smaller with the increase of the coating thickness ratio, that the SIF of the crack close to the boundary becomes smaller with the increase of the distance between the crack and the boundary, and that the SIF of the crack in the middle of the interface becomes larger with the decrease of the crack distance.

Research on Stress Intensity Factor of the Interface Crack in the Hard Cladding Material Structure under Mechanical Impact Load

2013 ◽  
Vol 589-590 ◽  
pp. 384-389 ◽  
Author(s):  
Jun Ru Yang ◽  
Ran Zhu ◽  
Gong Ling Chen ◽  
Yue Kan Zhang
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Amplitude ◽  
Impact Load ◽  
Thickness Ratio ◽  
Material Structure ◽  
Mechanical Impact ◽  
Impact Stress ◽  
Cladding Material

In the paper, the crack parallel to and lying on the interface in the hard cladding material structure is regarded as the research object, theoretical model of the stress intensity factor (SIF) of the interface crack under the mechanical impact load is built. Based on it, the SIF of the crack parallel to and lying on the interface in the cermet cladding material structure under the mechanical impact load is investigated by using finite element analysis method. The influences of the cladding thickness ratio and mechanical impact stress amplitude on the interface SIF are investigated. The research results show that, at a certain moment, the interface SIFs decrease with increasing cladding thickness ratio when the mechanical impact stress amplitude is a constant and increase as the mechanical impact stress amplitude increases when the cladding thickness ratio is a constant.

Stress Intensity Factor of Interface Crack in the Cermet Cladding Material Structure under Steady Mechanical-Thermal Coupled Loads

2016 ◽  
Vol 723 ◽  
pp. 394-399
Author(s):  
Jun Ru Yang ◽  
Yu Rong Chi ◽  
Ming Lan Wang ◽  
Ran Zhu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Interface Crack ◽  
Mechanical Load ◽  
Theoretical Models ◽  
Material Structure ◽  
The Finite Element Method ◽  
Coupled Loads ◽  
Cladding Material

In the paper, the crack parallel to and lying on the interface in the hard cermet cladding material structure is taken as the study object. Theoretical models of the stress intensity factor (SIF) of the interface crack under steady mechanical-thermal coupled loads are built. Based on which the interface crack SIFs in the cermet cladding material of 5Cr2Ni08C/Q235 under the same loads are analyzed with the finite element method. The crack SIF change laws under the coupled loads are obtained. KI increases with the increase of the temperature, the mechanical load and the crack length respectively. The absolute values of KII have the same change laws. And KI corresponding to the coupled loads is bigger than that to the single load. The research results are very important to develop the interface crack propagation theory. And they will also improve the optimization designs of the hard cladding material parts, and expand their applications.

Effect of specimen crack lengths on stress intensity factor for Al6061-TiC composites using experimental and 3D numerical methods

2017 ◽  
Vol 8 (5) ◽  
pp. 506-515 ◽  
Author(s):  
Raviraj M.S. ◽  
Sharanaprabhu C.M. ◽  
Mohankumar G.C.
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
Finite Element Simulations ◽  
Experimental Results ◽  
Crack Mouth Opening Displacement ◽  
3D Finite Element ◽  
Content Type

Purpose The purpose of this paper is to present the determination of critical stress intensity factor (KC) both by experimental method and three-dimensional (3D) finite element simulations. Design/methodology/approach CT specimens of different compositions of Al6061-TiC composites (3wt%, 5wt% and 7wt% TiC) with variable crack length to width (a/W=0.3-0.6) ratios are machined from as-cast composite block. After fatigue pre-cracking the specimens to a required crack length, experimental load vs crack mouth opening displacement data are plotted to calculate the KC value. Elastic 3D finite element simulations have been conducted for CT specimens of various compositions and a/W ratios to compute KC. The experimental results indicate that the magnitude of KC depends on a/W ratios, and significantly decreases with increase in a/W ratios of the specimen. Findings From 3D finite element simulation, the KC results at the centre of CT specimens for various Al6061-TiC composites and a/W ratios show satisfactory agreement with experimental results compared to the surface. Originality/value The research work contained in this manuscript was conducted during 2015-2016. It is original work except where due reference is made. The authors confirm that the research in their work is original, and that all the data given in the article are real and authentic. If necessary, the paper can be recalled, and errors corrected.

Research on Fracture Behavior of a Cracked Film-Substrate Medium

2006 ◽  
Vol 324-325 ◽  
pp. 903-906
Author(s):  
Bao Liang Liu ◽  
Xian Shun Bi
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Boundary Element Method ◽  
Intensity Factor ◽  
Boundary Element ◽  
Fracture Behavior ◽  
Thickness Ratio ◽  
Film Substrate ◽  
Substrate Medium ◽  
Element Method

This study gives the problem of a crack in the film oriented perpendicular to the film-substrate interface with the crack tip terminating at the interface. Based on Beuth’s theory, three-dimensional model is simplified to plane strain problems, which obtains fracture mechanisms of a cracked film-substrate medium by applying the boundary element method(BEM). The method aptly resolves the problem involving stress concentration and, further, that this study develops the multi-region boundary element method and applies it to evaluate the cracked film-substrate medium. It shows that the stress intensity factor is affected by the different elastic mismatches and the thickness ratio of the film and the substrate. These results indicate: 1) The stress intensity factor has remarkable increased with the decrease of the thickness ratio of the film and the substrate. The effect of the fracture behavior of film is negligible when the thickness ratio of the film and the substrate is above 10, therefore, it is treated as thin film; 2) The stress intensity factor will decrease with the increase of α ( −1 pα p +1) for β = 0 and β =α / 4 , where α and β are called Dundurs parameters. What’s more, this paper studies the special condition of the film-substrate medium, which is the analysis of the fracture of the absence of any elastic mismatch between the film and the substrate, i.e.α=β=0, and revision of the formula of Xia and Hutchinson is put forward for the stress intensity factor of the deep crack problems by comparing to the former conclusions of Y.Murakami.

The Investigation of Significance of the Geometrical Nonlinearity for 1-D Crack Stress Intensity Factor Calculation in Slightly Distorted Thin-Walled Pressurized Pipe

2015 ◽  
Author(s):  
Igor Orynyak ◽  
Andrii Oryniak
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cross Section ◽  
Crack Depth ◽  
Geometrical Nonlinearity ◽  
Circumferential Stress ◽  
Thickness Ratio ◽  
Inner Pressure ◽  
Thin Walled

The consideration of a geometrical nonlinearity is a common practice for the thin-walled structures. The relevance here are two well-known cases treated in ASME codes. First one is accounting for reduction of the pipe bends flexibility due to the inner pressure. The second one is the retarded increasing (and subsequent saturation) of additional local bending stress with increasing of inner pressure in a pipe with initial cross section form distortion. In both cases the rerounding effect and decreasing of local flexibilities take place. The crack can be treated as the concentrated flexibility and it is quite natural to expect that the stress intensity factor should grow nonlinearly with applied load. Two cases of SIF calculation for 1-D long axial surface crack in a pipe loaded by inner pressure are considered here: a) cross section has an ideal circular form: b) the form has a small distortion and crack is located in the place of maximal additional bending stresses. The theoretical analysis is based on: a) the well known crack compliance method [1] and b) analytical linearized solution obtained for deformation of the curved beam in case of action of fixed circumferential stress due to pressure written in the form convenient for transfer matrix method application. It was shown that for moderately deep crack (crack depth to the wall thickness ratio is 0.5 and bigger) and typical dimensions of pipes used for oil and gas transportation (radius to thickness ratio is 25–40) and loading which can reach up to 200 to 300 MPa, the effect investigated can be quite noticeable and can lead to 5–15 percent reduction of calculated SIF as compared with linear calculation. The analytical results are supported by nonlinear FEM calculation.

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