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| 2. |
- Zang, Weilin, et al.
(författare)
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A Boundary Integral Method For Internal Piece-Wise Smooth Crack Problems
- 1988
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Ingår i: International Journal of Fracture. - 0376-9429 .- 1573-2673. ; 38:4, s. 275-294
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Tidskriftsartikel (refereegranskat)abstract
- A new boundary integral method for plane elasticity problems with internal piece-wise smooth cracksis presented. The method can be applied to both infinite and finite geometries. A numerical technique which combines a collocation method for the cracks and the standard BEM technique for the outer boundary is used to solve the integral equations. Numerical examples are presented and compared either to existing solutions or to FEM calculations. All of the results provided by the present method are shown to be very accurate for both smooth and kinked cracks in both finite and infinite geometries.
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| 3. |
- Melin, Solveig
(författare)
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Fracture from a straight crack subjected to mixed mode loading
- 1987
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Ingår i: International Journal of Fracture. - 0376-9429. ; 32:4, s. 257-263
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Tidskriftsartikel (refereegranskat)abstract
- Fracture from a straight crack under mixed mode loading conditions and small scale of yielding is studied. It is assumed that crack growth occurs in either mode I or mode II. Comparison of theoretically obtained values of the mode I stress intensity factor at incipient kinking with experimental results indicates that mode I is preferred to mode II when the loading is such that the crack surfaces are traction-free, i.e. in the absence of a confining pressure. Mode II would be preferred only if the ratio K II c/K I c between the stress intensity factors is very low, between 0.38–0.81, depending on the load situation. Since there are reasons to believe that most materials are characterized by higher values of K II c/K I c, the conclusion is that mode II hardly occurs in the absence of a high confining pressure.
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| 4. |
- Melin, Solveig
(författare)
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On singular integral equations for kinked cracks
- 1986
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Ingår i: International Journal of Fracture. - 0376-9429. ; 30:1, s. 57-65
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Tidskriftsartikel (refereegranskat)abstract
- Chebyshev polynomial techniques for solution of singular integral equations leading to square root singularities at the ends of the interval of integration are studied. It is shown that the results are less accurate when a singularity, albeit a weak one, appears between the interval ends. Typical examples are problems involving kinked cracks. Some attempts to improve the accuracy are discussed.
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| 5. |
- Melin, Solveig
(författare)
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When does a crack grow under mode II conditions?
- 1986
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Ingår i: International Journal of Fracture. - 0376-9429. ; 30:2, s. 103-114
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Tidskriftsartikel (refereegranskat)abstract
- Even cracks which seem to be favourably oriented for mode II growth might extend in mode I by kinking. The conditions that favour mode I or mode II growth are examined. It is shown that a high confining pressure promotes mode II growth and so does a low ratio between the critical stress intensity factors of modes II and I. Quantitative results are given for different coefficients of friction and confining pressures.
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| 6. |
- Ståhle, P.
(författare)
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A One-Step Solution Technique for Elastic-Plastic Self-Similar Problems
- 1986
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Ingår i: International Journal of Fracture. - 0376-9429. ; 30:1, s. 5-12
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Tidskriftsartikel (refereegranskat)abstract
- At self-similarity the strain history is implicit in and deducible from the strain field at each instance of the loading process. This fact is taken advantage of in a FEM-technique which allows the load to be applied in one single step, only, even when the incremental theory of plastic flow has to be used.Two self-similar problems are solved. Firstly an analytically solvable anti-plane strain crack problem is treated and the numerical one step solution is found to agree very well with the analytical one and significantly better than a step-by-step solution. Secondly a mode I crack problem for asymptotic small scale yielding in plane stress is examined. The result suggests that the plasticity correction for the crack length is significantly less than estimated by Tada et al. [1].
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