Estimation of Time-dependent Damage Paths of Armors of Rubble-mound Breakwaters using Stochastic Processes

摘要

The progressive degradation paths of structures have quantitatively been tracked by using stochastic processes,such as Wiener process,gamma process and compound Poisson process,in order to consider both the sampling uncertainty due to the usual lack of damage data and the temporal uncertainty associated with the deterioration evolution.Several important features of stochastic processes which should carefully be considered in application of the stochastic processes to practical problems have been figured out through assessing cumulative damage and lifetime distribution as a function of time.Especially,the Wiener process and the gamma process have straightforwardly been applied to armors of rubble-mound breakwaters by the aid of a sample path method based on Melby's formula which can estimate cumulative damage levels of armors over time.The sample path method have been developed to calibrate the related-parameters required in the stochastic modelling of armors of rubble-mound breakwaters.From the analyses,it is found that cumulative damage levels of armors have surely been saturated with time.Also,the exponent of power law in time,that plays a significant role in predicting the cumulative damage levels over time,can easily be determined,which makes the stochastic models possible to track the cumulative damage levels of armors of rubble-mound breakwaters over time.Finally,failure probabilities with respect to various critical limits have been analyzed throughout its anticipated service life.