Author: Bernard GrossPublisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 24
Book Description
Stress-intensity Factors for a Single-edge-notch Tension Specimen by Boundary Collocation of a Stress Function
Author: Bernard GrossPublisher:
ISBN:
Category : Fracture mechanics
Languages : en
Pages : 24
Book Description
Stress-intensity Factors for Single-edge-notch Specimens in Bending Or Combined Bending and Tension by Boundary Collocation of a Stress Function
Author: Bernard GrossPublisher:
ISBN:
Category : Bending moment
Languages : en
Pages : 22
Book Description
A boundary-value-collocation procedure was used in conjunction with the Williams stress function to determine values of the stress-intensity factor K for single edge cracks of various depths in specimens subjected to pure bending. The results are of use in connection with K(sub Ic) fracture toughness tests, which utilize rectangular-section crack-notch beam specimens loaded in four-point bending, and are in good agreement with published results derived from experimental compliance measurements. The results are expressed in convenient, compact form in terms of the dimensionless quantity Y(exp 2)=K(exp 2)B(exp 2)W(exp 3)/M(exp 2), which is a function of relative crack depth a/W only, where B and W are the specimen width and thickness and M is the applied bending moment. On the assumption that the condition for a valid K(sub Ic) test is that the maximum nominal stress at the crack tip should not exceed the yield strength of the material, the K(sub Ic) measurement capacity of bend specimens was estimate as a function of a/W. The measurement capacity is proportional to the yield strength and to the square root of the specimen depth, and it is greatest for a/W in the range 0.2 to 0.3. Values of K for single-edge-notch specimens subjected to combined bending and tension were obtained by superposition of the present results and those of earlier work for specimens loaded in uniform tension. These values are of interest in connection with the use of single-edge-notch specimens that are off-center pin-loaded in tension. It is shown that the K(sub Ic) measurement capacity of such specimens is not very sensitive to the eccentricity of loading.
Stress-intensity Factors for Three-point Bend Specimens by Boundary Collocation
Author: Bernard GrossPublisher:
ISBN:
Category : Biharmonic equations
Languages : en
Pages : 20
Book Description
A boundary value collocation procedure was applied to the Williams stress function to determine values of the stress intensity factor K for single edge in rectangular section specimens subjected to three point bending. The results are presented in terms of the dimensionless quantity Y2 = K2B2W3/M2 where B and W are the specimen thickness and depth and M is the bending moment at midspan. The values of Y2 as a function of relative crack depth a/W for three-point bending are appreciably lower than the corresponding values for pure bending (determined previously by the same method) and decrease as the ratio of support span to specimen depth S/W decreases. Plots of Y2 against a/W are given for values of a/W up to 0. 5 and S/W equal to 4 and 8. The results were relatively insensitive to variations in the spread of the midspan load contact region, which was assumed to be related to the yield strength of the material. The results agreed fairly well with published results derived from experimental compliance measurements; one set gave higher values of Y2 than the present method, and the other set gave lower values. The plane-strain fracture toughness measurement capacity of three-point bend specimens is somewhat lower than that of four- point bend specimens, but the difference is of negligible practical importance.
Stress-intensity Factors by Boundary Collocation for Single-edge-notch Specimens Subject to Splitting Forces
Author: Bernard GrossPublisher:
ISBN:
Category : Cracking process
Languages : en
Pages : 54
Book Description
A boundary -value-collocation procedure was applied in conjunction with the Williams stress function to determine values of the stress-intensity factor K1 for single-edge cracks in plate specimens subject to splitting forces applied close to the crack and acting transversely to it. The results are presented in terms of the dimensionless quantity Y = K1BH3 /2/pa, where B and H are the specimen thickness and half-depth, a is the effective crack length, and P is the applied load. The results are practically independent of the ratio of effective specimen length to specimen half-depth q/H, when this ratio is not less than a/H + 2, and are then in excellent agreement with those derived by other investigators from compliance measurements. In the limit, as H/a approaches zero, the value of Y approaches that obtained in an elementary analysis which treats the specimen as a pair of built-in cantilever beams.
NASA Technical Note
Author: USAF Damage Tolerant Design Handbook
Author: Fracture Toughness Testing and Its Applications
Author: ASTM Committee E-24 StaffPublisher: ASTM International
ISBN: 9780803101050
Category : Technology & Engineering
Languages : en
Pages : 430
Book Description
Fracture Mechanics and Crack Growth
Author: Naman RechoPublisher: John Wiley & Sons
ISBN: 111856328X
Category : Technology & Engineering
Languages : en
Pages : 347
Book Description
This book presents recent advances related to the following two topics: how mechanical fields close to material or geometrical singularities such as cracks can be determined; how failure criteria can be established according to the singularity degrees related to these discontinuities. Concerning the determination of mechanical fields close to a crack tip, the first part of the book presents most of the traditional methods in order to classify them into two major categories. The first is based on the stress field, such as the Airy function, and the second resolves the problem from functions related to displacement fields. Following this, a new method based on the Hamiltonian system is presented in great detail. Local and energetic approaches to fracture are used in order to determine the fracture parameters such as stress intensity factor and energy release rate. The second part of the book describes methodologies to establish the critical fracture loads and the crack growth criteria. Singular fields for homogeneous and non-homogeneous problems near crack tips, v-notches, interfaces, etc. associated with the crack initiation and propagation laws in elastic and elastic-plastic media, allow us to determine the basis of failure criteria. Each phenomenon studied is dealt with according to its conceptual and theoretical modeling, to its use in the criteria of fracture resistance; and finally to its implementation in terms of feasibility and numerical application. Contents 1. Introduction. Part 1: Stress Field Analysis Close to the Crack Tip 2. Review of Continuum Mechanics and the Behavior Laws. 3. Overview of Fracture Mechanics. 4. Fracture Mechanics. 5. Introduction to the Finite Element Analysis of Cracked Structures. Part 2: Crack Growth Criteria 6. Crack Propagation. 7. Crack Growth Prediction in Elements of Steel Structures Submitted to Fatigue. 8. Potential Use of Crack Propagation Laws in Fatigue Life Design.
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