## Abstract

Transient mode I stress intensity factors (K(IT)) distributions along semi-elliptical crack fronts resulting from thermal shock typical to a firing gun are investigated. K(IT) distributions for various crack arrays of n = 2 to 48 cracks, bearing cracks of relative depths of a/W = 0.1 to 0.4 and with ellipticities of a/c = 0.5, 1.0 and 1.5 are evaluated for a cylindrical pressure vessel of radii ratio of R_{0}/R(i) = 2. As decoupling between the thermal and the elastic problems is assumed, the solution is performed in two steps via the finite element (FE) method using the standard ANSYS 5.0 code. In the first step temperature distributions through the vessel's wall are evaluated for various time steps in the interval 2 to 10 msec assuming convective boundary conditions. The temperature fields evaluated in the first step serve as input to the second step, the elastic analysis, in which K(IT) is evaluated. The results show that K(IT) is usually negative, as could have been anticipated, and reaches its largest negative value at the intersection of the crack plane with the inner surface of the cylinder. In general, the negative magnitude of K(IT) increases as the number of cracks in the array decreases, as the crack ellipticity increases, and as time elapses from firing.

Original language | English |
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Pages (from-to) | 161-170 |

Number of pages | 10 |

Journal | International Journal of Fracture |

Volume | 99 |

Issue number | 3 |

State | Published - 1 Dec 1999 |

## Keywords

- Cylindrical pressure vessel
- Finite element
- Semi-elliptical crack
- Stress intensity factor
- Thermal shock