The laying of subsea pipelines is usually carried out by means of S-lay technology. As stingers become longer and longer, wave-induced fatigue damage problem for the stinger main hinges connecting both the stinger and the stinger adjustment frame fore leg to the vessel stern via a common shaft may have to be taken into consideration. Usually, there is a structural health monitoring system (SHMS) to be installed on the stinger for performance assessment. A procedure for assessing long-term wave-induced fatigue damage to a stinger is thus presented in this paper with continuum damage mechanics (CDM)-based fatigue damage assessment method. By taking the stinger of DPV7500 being built for Chinese Offshore Oil Engineering Corporation (COOEC) as an example, a structural health monitoring-oriented finite element model of the stinger is established. Water tank experiments were conducted to measure the roll, pitch and heave motion responses of the vessel model for different wave height, wave period and directions. The measurement data are then used to carry out the stress analyzes of the stinger to identify stress characteristics at hot spots of the stinger. The accumulative fatigue damage at hot spots during the stinger design life is finally evaluated using a CDM-based fatigue damage evolution model.
Fatigue damage and sensor development for aircraft structural health monitoring