Stress Analysis And Research On Corrosion Of Crane Boom On Pipe-laying Vessel

Cranes on pipe-laying vessels have made a great contribution to our country in offshore oil and gas exploitation and its transportation. In practical application, many equipment structures have corrosion protection measures. But, as time goes on, corrosion of booms, especially those who have been used over20years, becomes a serious problem due to the extreme working environment and poor equipment maintenance. Corrosion affects equipment’s performance and safety in certain extent, so it is widespread concerned by practical engineers. However, there are few studies about crane boom’s corrosion at home and abroad. Researching on this problem is of great importance.This paper takes the boom of300tons crane on pipe-laying vessel as analysis object and uses FEA software to analyze stress trends of single corrosion point and double corrosion points on the basis of boom’s current corrosion status. According to the conclusion, a repairing solution is given and the crane’s lifting performance is reevaluated after it is repaired. This would provide references for practical engineering. The main work of this paper can describe as follows:(1) According to the on-site survey and relevant inspection reports, the boom corrosion status and reason are analyzed. The boom’s FEA model without corrosion is built to analyze its stress under typical operating conditions. Based on this, main stress source of its chords and bracings is analyzed, which is the foundation of the following research.(2) According to the existed research achievements and actual shape of the corrosion points, FEA models of local single corrosion point and two corrosion points for boom’s chords and bracings are built.(3) By analyzing the stress effect on chords and bracings of different corrosion width and depth, law curves are acquired. By fitting these date, equations that describe the relationship between stress and corrosion status (width and depth) are given.(4) By analyzing the effect on stress when the two corrosion points of chords and bracings are in different corrosion depth ratios, corrosion distance and arranged position, tendency curves are obtained. Then, the common limitation affected parameter values are gained to decide whether the two corrosion points are affected or not. (5) According to current corrosion situation of the boom, the repair program for point corrosion is given. Its scope of application and repairing effect is analyzed. Based on this, the boom’s lifting performance is reevaluated reasonably.