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.

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.

Analysis of Dynamic Stress Intensity Factors for Cracked Stiffened Plates Based on Extended FE Method

2020 ◽  
Vol 162 (A1) ◽  
Author(s):  
Y Peng ◽  
P Yang
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Dynamic Stress ◽  
Mesh Size ◽  
Stiffened Plates ◽  
Intensity Factors ◽  
Time Step ◽  
Dynamic Stress Intensity Factors ◽  
Crack Location

The dynamic stress intensity factors (DSIFs) for cracked stiffened plates considering the actual boundary conditions in ship structures are analyzed by the extended finite element method (XFEM). The sensitivity of numerical results with respect to mesh size and time step is discussed. Some other influential parameters including stiffener height, crack location and crack length are also analyzed. The numerical results show that the convergence is affected by mesh size and time step. By using XFEM, singular elements are not needed at the crack front and moderately refined meshes can achieve good accuracy. The height of the stiffener and crack location significantly effect DSIFs, while the crack length slightly influences the DSIFs.

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.

ANALYSIS OF DYNAMIC STRESS INTENSITY FACTORS FOR CRACKED STIFFENED PLATES BASED ON EXTENDED FE METHOD

2021 ◽  
Vol 162 (A1) ◽  
Author(s):  
Y Peng ◽  
P Yang
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Dynamic Stress ◽  
Mesh Size ◽  
Stiffened Plates ◽  
Intensity Factors ◽  
Time Step ◽  
Dynamic Stress Intensity Factors ◽  
Crack Location

The dynamic stress intensity factors (DSIFs) for cracked stiffened plates considering the actual boundary conditions in ship structures are analyzed by the extended finite element method (XFEM). The sensitivity of numerical results with respect to mesh size and time step is discussed. Some other influential parameters including stiffener height, crack location and crack length are also analyzed. The numerical results show that the convergence is affected by mesh size and time step. By using XFEM, singular elements are not needed at the crack front and moderately refined meshes can achieve good accuracy. The height of the stiffener and crack location significantly effect DSIFs, while the crack length slightly influences the DSIFs.

A Coupled SBFEM-FEM Approach for Evaluating Stress Intensity Factors

2013 ◽  
Vol 353-356 ◽  
pp. 3369-3377 ◽  
Author(s):  
Ming Guang Shi ◽  
Chong Ming Song ◽  
Hong Zhong ◽  
Yan Jie Xu ◽  
Chu Han Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Geometry ◽  
Stress Singularity ◽  
Intensity Factors ◽  
Finite Element Software ◽  
Scaled Boundary Finite Element ◽  
Element Method

A coupled method between the Scaled Boundary Finite Element Method (SBFEM) and Finite Element Method (FEM) for evaluating the Stress Intensity Factors (SIFs) is presented and achieved on the platform of the commercial finite element software ABAQUS by using Python as the programming language. Automatic transformation of the finite elements around a singular point to a scaled boundary finite element subdomain is realized. This method combines the high accuracy of the SBFEM in computing the SIFs with the ability to handle material nonlinearity as well as powerful mesh generation and post processing ability of commercial FEM software. The validity and accuracy of the method is verified by analysis of several benchmark problems. The coupled algorithm shows a good converging performance, and with minimum additional treatment can be able to handle more problems that cannot be solved by either SBFEM or FEM itself. For fracture problems, it proposes an efficient way to represent stress singularity for problems with complex geometry, loading condition or certain nonlinearity.

Determination of Stress Intensity Factors for Gradient Stress Fields

1977 ◽  
Vol 99 (3) ◽  
pp. 477-484 ◽  
Author(s):  
J. M. Bloom ◽  
W. A. Van Der Sluys
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Maximum Stress ◽  
Nuclear Industry ◽  
Stress Fields ◽  
Polynomial Method ◽  
Intensity Factors ◽  
Asme Code ◽  
Linear Envelope

This paper evaluates eight different analytical procedures used in determining elastic stress intensity factors for gradient or nonlinear stress fields. From a fracture viewpoint, the main interest in this problem comes from the nuclear industry where the safety of the nuclear system is of concern. A fracture mechanics analysis is then required to demonstrate the vessel integrity under these postulated accident conditions. The geometry chosen for his study is that of a 10-in. thick flawed plate with nonuniform stress distribution through the thickness. Two loading conditions are evaluated, both nonlinear and both defined by polynomials. The assumed cracks are infinitely long surface defects. Eight methods are used to find the stress intensity factor: 1–maximum stress, 2–linear envelope, 3–linearization over the crack length from ASME Code, Section XI, 4–equivalent linear moment from ASME Code, Section III, Appendix G for thermal loadings, 5–integration method from WRC 175, Appendix 4 for thermal loadings, 6–8-node singularity (quarter-point) isoparametric element in conjunction with the displacement method, 7–polynomial method, and 8–semi-infinite edge crack linear distribution over crack. Comparisons are made between all eight procedures with the finding that the methods can be ranked in order of decreasing conservatism and ease of application as follows: 1–maximum stress, 2–linear envelope, 3–linearization over the crack length, 4–polynomial method, and 5–singularity element method. Good agreement is found between the last three of these methods. The remaining three methods produce nonconservative results.

Experimental Determination of Side Boundary Effects on Stress Intensity Factors in Surface Flaws

1975 ◽  
Vol 97 (1) ◽  
pp. 45-51 ◽  
Author(s):  
M. Jolles ◽  
J. J. McGowan ◽  
C. W. Smith
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Taylor Series ◽  
Stress Intensity Factors ◽  
Taylor Series Expansion ◽  
Correction Method ◽  
Intensity Factors ◽  
Surface Flaws ◽  
Plate Width

A technique consisting of stress-freezing photoelasticity coupled with a Taylor Series Expansion of the maximum local in-plane shearing stress known as the Taylor Series Correction Method (TSCM) is applied to the determination of stress intensity factors (SIF’s) in flat bottomed surface flaws of flaw depth/length ratios of approximately 0.033. Flaw depth/thickness ratios of approximately 0.20 and 0.40 were studied as were plate width/crack length ratios of approximately 2.33 and 1.25, the former of which corresponded to a nearly infinite width. Agreement to well within 10 percent was found with the Rice-Levy and Newman theories using a depth-modified secant correction and equivalent flaw depth/length ratios. The Shah-Kobayashi Theory, when compared on the same basis, was lower than the experimental results. Using a modified net section stress correction suggested by Shah, agreement with the Shah-Kobayashi Theory was greatly improved but agreement with the other theories was poorer. On the basis of the experiments alone, it was found that the SIF was intensified by about 10 percent by decreasing the plate width/crack length from 2.33 to 1.25.

scholarly journals Theoretical and Numerical Study on Stress Intensity Factors for FRP-Strengthened Steel Plates with Double-Edged Cracks

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2356 ◽  
Author(s):  
Hai-Tao Wang ◽  
Gang Wu ◽  
Yu-Yang Pang
Keyword(s):  
Stress Intensity ◽  
Shear Modulus ◽  
Crack Length ◽  
Correction Factor ◽  
Stress Intensity Factors ◽  
Steel Plate ◽  
Numerical Study ◽  
Steel Plates ◽  
Intensity Factors ◽  
Adhesive Thickness

This paper presents a theoretical and numerical study on the stress intensity factors for double-edged cracked steel plates strengthened with fiber reinforced polymer (FRP) plates. Based on the stress intensity factor solution for infinite center-cracked steel plates strengthened with FRP plates, expressions of the stress intensity factors were proposed for double-edged cracked steel plates strengthened with FRP plates by introducing two correction factors: β and f. A finite element (FE) simulation was carried out to calculate the stress intensity factors of the steel plate specimens. Numerous combinations of the specimen width, crack length, FRP thickness and Young’s modulus, adhesive thickness, and shear modulus were considered to conduct the parametric investigation. The FE results were used to investigate the main influencing factors of the stress intensity factors and the correction factor, β. The expression of the correction factor, β, was formulated and calibrated based on the FE results. The proposed expressions of the stress intensity factors were a function of the applied stress, the crack length, the ratio between the crack length and the width of the steel plate, the stiffness ratio between the FRP plate and steel plate, the adhesive thickness, and the shear modulus. Finally, the theoretical results and numerical results were compared to validate the proposed expressions.

scholarly journals Influence of Pressure and Thermal Parameters on Stresses Analysis of Pressurized and Cracked Pipes

2019 ◽  
Vol 35 (6) ◽  
pp. 1640-1646
Author(s):  
Abdullah K. Okab ◽  
Khalid A. Mohammed ◽  
Abdurahman A. Gatta
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
J Integral ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Modeling Process ◽  
Oil Gas ◽  
Pressurized Cylinder

Due to the dangerous alarm for many engineering applications such as energy generating systems and pipelines transporting oil, gas and its derivatives under high-pressure, a study of the effect of thermal and mechanical loading on the cracked materials and pipes at high-temperature environments is required. In this work, the influence of the thermal loadings on stresses analysis of pressurized and cracked pressurized pipes has been solved numerically where the mode I crack's type has been considered. The modeling process mainly aims to find the stress intensity factor, J-integral calculations and the stress distributions. The accuracy of the results has been compared with analytical solutions of a pressurized cylinder. The mesh around the crack have been modeled in a careful way to obtain accurate stress distributions. It was found that the surface’s temperature has a significant effect on stress distributions, for example, the stresses increased by 50% with increasing the temperature differences between the inner and outer pipe’s diameter. Additionally, the stress intensity factor and the J-integrals values were calculated for different crack length ratios and temperature differences. It is found at the crack length ratio of 0.6 the stress intensity factors increased up to 50% from 45 to 76 and J-integral increased by 77% from 250 kN/m to 430 kN/m. Also, the influence of fluid’s temperature investigated, and the result showed that by increasing the fluid’s temperature without cracks, the stresses decreased by 33%. Also, it was found that for different crack length ratios the J-integral and stress intensity reduces when the fluid’s temperature increases.

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