RELIABILITY ANALYSIS OF DYNAMIC STRUCTURES

In this paper the concepts to compute reliabilities for stationary and ergodic conditions in the presence of time-invariant non-ergodic parameters will first be reviewed. Focus wili be on numerical techniques like FORM and numerical integration. The effect of correlation between the environmental processes within a sea state is studied, as opposed to between sea state correlation that turns out to be unimportant. The system reliability of jack-up structures is discussed using a combination of dynamic simulation of a stick model and the static analysis of a detailed jack-up model. First, the dynamic time domain simulation, the quasi-static time-domain simulation and the design wave analysis are applied for different sea-states using a stick structural model. In the second phase, the concepts of Dynamic Amplz~cation Factors (DAF) and Calibration Fhctors (CF) are introduced for extreme responses of a detailed structural model of jack-up structure. To utilize the analogical quantities for stick and detailed structural models, the design wave responses of the detailed structural model are linked with the extreme responses and the probabilistic models of dynamic effects using a stick structural model.

Keywords:

Jack-up structure , failure mechanism , Dynamic Amplification Factor , stochastic dynamic analysis , system reliability