Ice induced low temperature fatigue crack propagation in offshore structural steel A131

To investigate the low temperature fatigue crack propagation behavior of of fshore structural steel A131 under random ice loading, three ice failure mo des that are commonly present in the Bohai Gulf are simulated according to the vibration stress responses induced by real ice loading. The test data a re processed by a universal software FCPUSL developed on the basis of the t heory of fatigue crack propagation and statistics. The fundamental paramete r controlling the fatigue crack propagation induced by random ice loading i s determined to be the amplitude root mean square stress intensity factor K -arm. The test results are presented on the crack propagation diagram where the crack growth rate da/dN is described as the function of K-arm. It is e vident that the ice failure modes have great influence on the fatigue crack propagation behavior of the steel in ice-induced vibration. However, some of the experimental phenomena and test results are hard to be physically ex plained at present. The work in this paper is an initial attempt to investi gate the cause of collapse of offshore structures due to ice loading.