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THE EFFECT OF PRESSURE OVERLOAD ON FATIGUE CRACK GROWTH IN PRESSURE VESSELS
Author(s) -
Shaniavski A. A.
Publication year - 1996
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1996.tb00927.x
Subject(s) - striation , hydrostatic pressure , materials science , paris' law , hydrostatic equilibrium , pressure vessel , crack closure , mechanics , structural engineering , composite material , fracture mechanics , engineering , physics , quantum mechanics
— The pressure‐overload method for proof‐testing pressure‐vessels was investigated for hydrofilters made of an Al‐alloy. After a vessel had been overloaded using a hydrostatic fluid, the fatigue crack growth rate of the material was studied at three levels of hydrodynamic pressure. The period of fatigue crack growth N p and the uniaxial equivalent stress σ e were calculated on the basis of fractographic analyses for various combinations of the hydrostatic overload and the hydrodynamic pressure. Increasing the overload level increased N p , and decreased σ e . For a pressure overload of 3 times the normal pressure the initiation of a fatigue crack did not occur after 2 × 10 6 cycles of loading at an hydrodynamic pressure of 20.6 MPa. Striation spacing could not be correlated against the value of the hydrodynamic pressure after an overload of 2.5 times the normal pressure. A unified relationship between the durability N d and the ratio N p / N d (= N d p ) at different hydrodynamic fluid pressures was demonstrated.