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.

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.

Reliability Analysis of the Cracked Ag-SU8 Interface on the Channel Wall in a Micro-PEMFC

2006 ◽  
Author(s):  
Chi-Hui Chien ◽  
Yi-San Shih ◽  
Shou-Shing Hsieh ◽  
Huang-Hsiu Tsai ◽  
Chih-Wei Lin ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Channel Wall ◽  
Crack Tip ◽  
Electrochemical Process ◽  
Shear Stresses ◽  
Intensity Factors ◽  
Compressive Stresses ◽  
And Performance

The efficiency of the fuel cell depends on both the kinetics of the electrochemical process and performance of the components. The main aim of this research is to analysis the reliability of the cracked Ag-SU8 interface on the channel wall in a micro-PEMFC. An existed surface crack on the channel wall subjected to the flow induced compressive stresses and shear stresses will propagate and lead to the spall formation. In this paper, at first, the flow induced compressive and shear stresses are obtained through simulation of stress state and flow-field in the micro-channel by commercial package software ANSYS® 8.0. Then, the stresses arising at the crack tip due to flow induced compressive and shear stresses can be calculated and characterized by the mode I and II stress intensity factors (SIF), KI and KII, respectively. Finally, the KI and KII stress intensity factors at the crack tip are computed for the different crack sizes and loadings. The results show that the inlet pressure and crack length affect the stress intensity factors more than the inlet velocity does. Also, the results show that as the crack length increases, the value of KI will increase, but the value of KII decreases slightly.

Effect of notch configuration and pre-crack length on stress intensity factors

2005 ◽  
Vol 47 (10) ◽  
pp. 561-567
Author(s):  
Hassan S. M. Hedia ◽  
Mohamed A. N. Shabara ◽  
Ahmed. A. Fattah ◽  
Mahmoud M. K. Helal
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Intensity Factors

scholarly journals Damage Process Simulation of Damping Coating of Thin Plate

2011 ◽  
Vol 2-3 ◽  
pp. 739-742 ◽  
Author(s):  
Jing Yu Zhai ◽  
Hui Li ◽  
Qing Kai Han
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Process Simulation ◽  
Intensity Factors ◽  
Interface Elements ◽  
Damage Process

In this paper, the element birth and death technique is used to simulate the damping stripping process of damping coating, and the interface of substrate and damping coating is simulated by contact elements or interface elements. The stress intensity factors and crack length are also calculated based on finite element method under different thicknesses and elastic modulus The simulation could provide reference for the design and optimize of damping coating.

The Effect of Crack Length Unevenness on Stress Intensity Factors Due to Autofrettage in Thick-Walled Cylinders

1997 ◽  
Vol 119 (3) ◽  
pp. 274-278 ◽  
Author(s):  
M. Perl ◽  
D. Alperowitz
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Relative Length ◽  
Intensity Factors ◽  
Residual Stress Field ◽  
Interaction Range ◽  
Wide Range ◽  
Level Model ◽  
Radial Cracks

The effect of crack length unevenness on the mode I stress intensity factors (SIFs) for large uniform arrays of radial cracks of unequal depth in fully or partially autofrettaged thick-walled cylinders is investigated. The analysis is based on the previously proposed “two-crack-length level model.” Values for KIA—the SIF due to the compressive residual stress field—for various crack arrays bearing n1 = n2 = 2−512 cracks, a wide range of nondimensional crack lengths l1/a=0.01−0.1, and numerous levels of autofrettage ε = 30−100 percent are evaluated by the finite element method for a cylinder of radii ratio of b/a = 2. The interaction range for different combinations of crack arrays and crack length is then determined. The obtained results show that the unevenness in the SIFs depends on all three parameters, i.e., the number of cracks in the array, the cracks’ lengths, and the level of autofrettage, while the interaction range between adjacent cracks is determined only by the relative length of the cracks and the density of the array.

Stress intensity factors for part-elliptical cracks emanating from dimpled rivet holes

2014 ◽  
Vol 03 (04) ◽  
pp. 1450022
Author(s):  
Ailun Wang ◽  
Chongmin She ◽  
Gang Lin ◽  
You Zhou ◽  
Wanlin Guo
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Empirical Formula ◽  
Shape Factor ◽  
Engineering Application ◽  
Least Square ◽  
Intensity Factors ◽  
Elliptical Shape ◽  
Corner Cracks

Detailed investigations on the stress intensity factors (SIFs) for corner cracks emanated from interference fitted dimpled rivet holes are conducted using three-dimensional finite element method. The influences of the crack length a, elliptical shape factor t, far-end stress S and interference magnitude δ on the stress intensity factors are systematically studied. The SIFs for corner cracks emanated from open holes are also investigated for comparisons. An empirical formula of the normalized SIF is proposed by use of the least square method for convenience of the engineering application, which is a function of the crack length a, elliptical shape factor t, far-end stress S, interference magnitude δ and the normalized elliptical centrifugal angle φn. Based on the empirical formula, a crack growth simulation for a rivet filled hole is conducted, which shows a good agreement with the test data.

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