Crack Growth in Externally Flawed, Autofrettaged Thick-Walled Cylinders and Rings

Kapp, J. A.; Eisenstadt, R.

doi:10.1520/stp34947s

Cited by 3 publications

(4 citation statements)

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“…Clearly, a re-pressurization of the tube to a pressure p < p* will produce a stress distribution which may be calculated by the addition of equations (7) and (1) for r d c, and equations (8) and (1) for r 3 c .…”

Section: Basic Equations For Pressurized Autofrettaged Tubesmentioning

confidence: 99%

“…The autofrettage pressure required to achieve this is given by equation (4). Substitute from equation (4) into (7) to obtain the residual stress field with full autofrettage, namely :…”

Section: Internally Cracked Partially Autofrettaged Tubementioning

confidence: 99%

“…To inhibit fatigue growth of internal cracks it is common practice to produce a more advantageous stress distribution, involving residual compressive hoop stresses near the bore, by autofrettage treatment of the cylinder prior to use [7].…”

Section: Introductionmentioning

confidence: 99%

“…It is worth noting that the stress distribution arising from full autofrettage is essentially equivalent to that arising from steady-state thermal loading of the tube [9], and that K values for one of these loadings may be obtained from the other by a simple scaling operation [S). However, the optimum autofrettage condition may not be 100% overstrain [7] since fatigue cracks may develop at the outside radius as a result of a relatively high tensile residual stress. Clearly, the choice of the optimum overstrain condition will involve a consideration of the rates at which external cracks will grow radially inwards, and the rates at which internal cracks will grow outwards.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Stress Intensity and Fatigue Crack Growth in Multiply‐cracked, Pressurized, Partially Autofrettaged Thick Cylinders*

Parker

1981

Fatigue Fract Eng Mat Struct

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Stress intensity factors are determined for internally and externally cracked, pressurized thick cylinders with partial autofrettage (less than 100% overstrain). The solutions are based on a superposition of existing solutions which does not involve any loss of accuracy. Implications of the stress intensity factor results for the safe‐life design of pressure vessels subjected to fatigue are discussed.

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Section: Basic Equations For Pressurized Autofrettaged Tubesmentioning

confidence: 99%

“…The autofrettage pressure required to achieve this is given by equation (4). Substitute from equation (4) into (7) to obtain the residual stress field with full autofrettage, namely :…”

Section: Internally Cracked Partially Autofrettaged Tubementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stress Intensity and Fatigue Crack Growth in Multiply‐cracked, Pressurized, Partially Autofrettaged Thick Cylinders*

Parker

1981

Fatigue Fract Eng Mat Struct

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Crack Growth Behavior of Pipes Made From Polyvinyl Chloride Pipe Material1

EL-Bagory

Younan

2016

Journal of Pressure Vessel Technology

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The behavior of crack growth of polymeric materials is affected by several operating conditions such as crosshead speed, specimen thickness, load line, and specimen configurations, which reverse the behavior of crack from stable to unstable crack growth behavior. The main objective of the present paper is the determination of plane strain fracture toughness (KIC) for polyvinyl chloride (PVC) used in piping water transmission systems. The dimensions of the PVC pipe are outside diameter, Do = 315 mm, standard dimensions ratio, SDR = 13.23, ratio between outside to inside radii Ro/Ri = 1.179, and pipe thickness, t = 24 mm. Curved specimens are prepared from a pipe by cutting 12 mm thickness ring segments. The curved specimens are divided into two specimen configurations, namely, curved three-point bend (CTPB) and C-shaped tension (CST) specimens. All specimens are provided artificially with a precrack. CTPB specimen is further cut into five 72 deg sectors with each being centrally notched to a depth approximately a = 0.479 of the wall thickness. CST specimen configuration is characterized by the eccentricity X = 0, and 0.5 W, of the loading holes from the bore surface. The linear elastic fracture mechanics theory (LEFM) is used to predict the plane strain fracture. The tests are carried out at room temperature, Ta equal 20 °C, and different crosshead speeds of (10–500 mm/min). The numerical analysis carried out within the frame of the present work is done using the finite element program Cosmos 2.6. Finite element method (FEM) is used to compute the stress intensity factor KQ surrounding the crack tip. The computed stress intensity factor can then be compared with that obtained by theoretical equation. The experimental fracture test results reveal that the crosshead speed has been proven to affect the mode of failure and mode of fracture. At lower crosshead speeds, the mode of failure is ductile, while at higher crosshead speeds, it is brittle. The specimen configuration also affects the fracture toughness. CST specimens show higher fracture toughness in the case of pin loading location X = 0.5W than X = 0 by about (12%). The transitional crosshead speed is affected by specimen geometry. CST specimens (CST) at X = 0 and 0.5W have higher transitional crosshead speed compared with the CTPB specimen configuration.

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Influence of Residual Stress on Fatigue Crack Growth in Thick-Walled Cylinders

Stacey

Webster²

1988

Analytical and Experimental Methods for Residual Stress Effects in Fatigue

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An investigation was conducted into fatigue crack growth in samples of as-received and autofrettaged, high-strength, low-alloy steel tubing containing residual stresses. Compact tension and C-shaped and ring specimens were used to measure properties in the axial and radial directions. Internally and externally flawed ring specimens were employed to propagate cracks through the original residual stress field. Experiments were performed for load ratios ranging between -0.5 and 0.8. Fatigue crack growth rates were substantially reduced by compressive residual stresses. The data were corrected for residual stress effects using the superposition principle. An effective stress intensity factor range, ΔKeff, was defined that incorporates the residual stress intensity factor, Kres, and the applied ΔK range. Using this approach, the correlation with the characteristics for no residual stress was very good. In addition, it was shown that fatigue crack growth rate characteristics measured with C-specimens can significantly misrepresent the actual behavior of the material and tubing under investigation if the remaining residual stress field is not taken into consideration.

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Crack Growth in Externally Flawed, Autofrettaged Thick-Walled Cylinders and Rings

Cited by 3 publications

References 0 publications

Stress Intensity and Fatigue Crack Growth in Multiply‐cracked, Pressurized, Partially Autofrettaged Thick Cylinders*

Stress Intensity and Fatigue Crack Growth in Multiply‐cracked, Pressurized, Partially Autofrettaged Thick Cylinders*

Crack Growth Behavior of Pipes Made From Polyvinyl Chloride Pipe Material1

Influence of Residual Stress on Fatigue Crack Growth in Thick-Walled Cylinders

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