Development And Research Of The Marine Shaft Alignment Software Based On FEM

The shaft alignment quality is very important to the running time of the marine and periods of construct, and it is the key for sail. Especially in modern time, with the appearing of building large ships, the study and application for shaft alignment is becoming one of the most important tasks which need to be solved.During the shipbuilding in major shipyards worldwide, plenty of problems are generated out of shaft alignment, which results in the over-tolerance of main engine crank shaft, high temperature of bearing and excessive vibration. The element leading to problems could be extremely complicated, for instance, insufficient consideration during the model setup; certain affecting elements vary with different types of ship, like the ship hull deformation, shaft vibration and bearing stiffness and so on; inadequate accuracy control and errors during the construction. All of the problems shall be dealt with certain scientific method and processed in the right manner.The marine propulsion shaft is a complex system, so it is a problem that how to choose the simple modal which can calculate the actual results . Based on lots of technical literature, this thesis chooses the rational alignment of shafting modal and explains how to deal with modal. Because of adopting the LDLT and FEM which has more accurate, it is easy to archive the goal. The development chooses the VC dialogue programming. The software can calculate the bearing force, offset, moment, deflection and shear, and make use of MATLAB6.5 to visualize the results.First, the shaft of CBVZ338-84 is studied. The software calculates the straight shaft alignment, shaft alignment hot condition, influence number of bearing load, jack-up factor, GAP and SAG. The results show that soft which has more accurate can be apply to the engineering application.Last, the shaft of some 110000tons oil tanker is calculated. From the contrast, the calculation results of the soft are consistent with that of foreign soft in cold condition, but not consistent in hot condition. That is to say, there are other factors which need to be considered.