A safety assessment approach of the salvage based on salvor–cable–wreck coupled simulations

Abstract

In order to accurately assess the safety of the whole salvage process, this paper presented a novel three-parameters safety assessment methodology on the basis of the time-domain analysis for a salvor–cable–wreck salvage system. A uniform criterion is eventually established by integrating different motion modes and comparable cases, which simplifies the description of the motion responses in the lifting operation. The water–soil–wreck interaction and salvor–cable interaction are respectively solved by the 8-degree finite element method and lumped mass method. Several groups of case studies under different sea states are numerically simulated and quantitatively assessed by utilizing the proposed method, out of the attention to the safety, stability, and energy efficiency in salvage engineering. According to the assessment scores, 30 and 150 deg could be selected as appropriate wave headings while the 180 deg wave direction is the safest. Also, small wave periods are found to be probable ideal sea states for sunken vessel salvage. The effect of the sunken object’s shape is relatively slight and mainly affects the stability of the salvor barge. Under larger wave heights or longer wave periods, the maximum tension and extra energy consumption of the lifting cables tend to increase.