A note on the finite element method in linear fracture mechanics

Mowbray, D. F.

doi:10.1016/0013-7944(70)90022-6

Cited by 33 publications

(9 citation statements)

References 3 publications

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“…Among the displacement-based methods of determining stress intensity factors, displacement extrapolation technique (DET), displacement correlation technique (DCT) and quarter point displacement technique (QPDT) are most widely used because of their simplicity and ease of implementation. The near crack tip nodal notation and the corresponding formulae of calculating stress intensity factors are shown in Figure 11 and (6)(7)(8), respectively. …”

Section: Comparison With Existing Cod Methodsmentioning

confidence: 99%

“…Secondly, in the early days of finite element applications to fracture mechanics, conventional elements used were unable to deal with the stress singularity at the crack tip so that either special crack-tip elements were used or special procedures were devised to circumvent the effect of inaccurate finite element results near the crack tip. Popularly adopted methods include extrapolation of/(-estimates from crack surface displacements away from the crack tip [5], calculation of energy changes from two or more finite element analyses with variation of crack length [5][6][7], and evaluation of the J-integral along paths away from the crack tip [5]. Later, Parks [8] modified the energy method using a stiffness derivative approach so that only one finite element analysis is required.…”

Section: Introductionmentioning

confidence: 99%

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A semi-infinite-crack model for determining mode I stress intensity factors using crack surface displacements

Lau

1996

Int J Fract

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A semi-infinite-crack model is used to supplement the conic section simulation method for determining stress intensity factors of finite cracked bodies under mode I loadings. The actual displaced crack surface profile is found by finite element analysis. For each crack surface segment between two neighbouring nodes, a set of model parameters is found by using the displacements of these two nodes. A stress intensity factor estimate is then calculated from the closed-form formula associated with the model. It is found that near-tip crack surface displacements produce model parameters that are sufficient for quantifying the stress intensity factor. The semiinfinite-crack model can be used either as a stand alone model or in conjunction with the ellipse simulation procedure to form a systematic approach. It is shown that this model can be applied to different geometries and loadings with excellent accuracy.

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Section: Comparison With Existing Cod Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A semi-infinite-crack model for determining mode I stress intensity factors using crack surface displacements

Lau

1996

Int J Fract

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“…This concept can be viewed as an application of Irwin's (1958) equation. Its application in the present study is similar to the procedure discussed by Dixon and Pook (1969) and by Mowbary (1970). The crack closure work is calculated according to W = 1/2 (fx~u + fy~uy)…”

Section: Calculation Of Stress Intensity Factorsmentioning

confidence: 96%

Stress analysis of high-level waste canisters: methods, applications, and design data

Simonen¹,

Slate²

1979

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The Pacific Northwest Laboratory (PNL) is conducting research and development studies on technology for immobilization of nuclear wastes. In this report, an overview of stress analysis methods, structural design procedures, and design data is presented for canisters used to package solidified wastes, particularly borosilicate glass. In addition, waste processing, canister materials, fabrication and inspection methods, and performance testing are summarized. Sources of stress in canisters are lifting and handling loads, internal pressure, hightemperature filling operations, transient heating and cooling, differential thermal expansions of canisters and glass, and impact loadings from low-probability accidents. Results of case studies that illustrate applicable methods of stress analyses are presented for these sources of stress. Existing sections of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code are reviewed and found to be applicable to canister fabrication, but the code does not cover many aspects of canister service loadings. Specialized criteria for minimum wall thicknesses to sustain filling stresses are proposed in this report. Results of a test program to measure the creep strength of candidate canister materials are described. Methods to predict residual stresses in the walls of waste canisters are described; predicted residual stress levels agree with measured stress levels. The consequences of these residual stresses are reviewed, and stress-corrosion cracking is identified as the mode of canister failure affected by residual stresses. Canister-closure design is covered in detail, particularly the welding and inspection of the final closure seal-weld. It is shown that the methods of fracture mechanics and fatiguecrack-growth analyses are valuable tools for evaluating the performance of closure welds in the presence of crack-like defects. Canister performance in process trials at PNL shows the ability of canisters to survive high temperatures and loadings during processing. The results of impact tests at PNL show that a suitably designed canister can sustain severe impacts without loss of integrity • iii

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“…Mowbray [8] used an energy method very similar to experimental compliance methods to compute the energy release rate. Mowbray [8] used an energy method very similar to experimental compliance methods to compute the energy release rate.…”

Section: Introductionmentioning

confidence: 99%

A stiffness derivative finite element technique for determination of crack tip stress intensity factors

1974

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A finite element technique for determination of elastic crack tip stress intensity factors is presented. The method, based on the energy release rate, requires no special crack tip elements. Further, the solution for only a sin#le crack length is required, and the crack is "advanced" by moving nodal points rather than by removing nodal tractions at the crack tip and performing a second analysis. The promising straightforward extension of the method to general three-dimensional crack configurations is presented and contrasted with the practical impossibility of conventional energy methods.

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A note on the finite element method in linear fracture mechanics

Cited by 33 publications

References 3 publications

A semi-infinite-crack model for determining mode I stress intensity factors using crack surface displacements

A semi-infinite-crack model for determining mode I stress intensity factors using crack surface displacements

Stress analysis of high-level waste canisters: methods, applications, and design data

A stiffness derivative finite element technique for determination of crack tip stress intensity factors

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