### STP1256: Stress-Intensity-Factor Influence Coefficients for Semielliptical Inner-Surface Flaws in Clad Pressure Vessels

Keeney, JA

*Engineers, Oak Ridge National Laboratory, Oak Ridge, TN*

Bryson, JW

*Engineers, Oak Ridge National Laboratory, Oak Ridge, TN*

Pages: 14 Published: Jan 1995

**Abstract**

A problem of particular interest in pressure vessel technology is the calculation of accurate stress-intensity factors for semielliptical surface cracks in cylinders. Computing costs for direct solution techniques can be prohibitive when applied to three-dimensional (3-D) geometries with time-varying boundary conditions such as those associated with pressurized thermal shock. An alternative superposition technique requires the calculation of a set of influence coefficients for a given 3-D crack model that can be superimposed to obtain mode-I stress-intensity factors. This paper presents stress-intensity-factor influence coefficients (SIFICs) for axially and circumferentially oriented finite-length semielliptical inner-surface flaws with aspect ratios [total crack length (2c) to crack depth (a)] of 2, 6, and 10 for clad cylinders having an internal radius (R^{i}) to wall thickness (t) ratio of 10. SIFICs are computed for flaw depths in the range of 0.01 ≤ a/t ≤ 0.5 and two cladding thicknesses. The incorporation of this SIFIC data base in fracture mechanics codes will facilitate the generation of fracture mechanics solutions for a wide range of flaw geometries as may be required in structural integrity assessments of pressurized-water and boiling-water reactors.

**Keywords:**

stress-intensity-factor influence coefficient, pressurized thermal shock, finite-length flaw, reactor pressure vessel, superposition

**Paper ID:** STP16399S

**Committee/Subcommittee:** E08.03

**DOI:** 10.1520/STP16399S

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