Fatigue Crack Growth Analysis of Structures Exposed to Fluids with Oscillating Temperature Distributions
SourceThis investigation considers amplitudes and frequencies of the oscillating temperature distribution as parameters for crack propagation studies. The alternating stresses produced by the temperature distribution are used to determine the ranges of stress intensity factors for a particular crack geometry using the principles of linear elastic fracture mechanics. The crack growth is then studied using a crack growth law for the material relating the crack growth per cycle to the number of cycles.
The analysis predicts that the number of cycles required to drive a crack of a specified initial size is dependent on the frequency of temperature cycling. The model also predicts that as the frequency increases, larger amplitudes of temperature variation can be permitted for the same number of cycles to failure. A design curve relating the temperature amplitude with the number of cycles to failure (a specified crack length) is obtained for various frequencies of temperature oscillations.