Research On Dynamic Alignment Method Of Ship Propulsion Shafting Considering Hull Deformation

With the development of ships in the direction of large-scale,the power of the main engine has also increased.In order to match the main engine,the size of the modern ship transmission shaft system is getting larger and larger.During the actual voyage,the ship will undergo varying degrees of hull deformation under the influence of factors such as loading,waves and temperature,resulting in changes in the relative position of the bearings,and the load,bending moment and rotation angle of each bearing will also follow change.At present,shipyards mainly use reasonable alignment techniques to install the shafting,but this method fails to fully consider the impact of dynamic factors such as hull deformation on the operation of the shafting.Based on this,this paper carries out related research around the influence of hull deformation on shaft alignment.This study did not analyze the effect of hull deformation of a specific ship type on shaft alignment through the whole ship modeling and simulation,but analyzes the measurement method of bearing relative displacement by studying the relationship between changes in bearing height and changes in bearing load And the calculation method of bearing load under large deformation.At the same time,the full calculation of the bearing load under extreme conditions is taken into account during the calibration calculation.The upper and lower limits of the bearing load are adjusted to ensure that the shaft system can still operate stably under complex sea conditions.Ensure the safety of ships.First,based on the principle of the influence number,the method of calculating the relative height change of the bearing using the change of the shafting parameter is discussed.Based on the measurement conditions of ships,the calculation method is optimized and adjusted based on reasonable assumptions.The change of bending moment can calculate the relative displacement of all bearings,and introduces the measuring principle,equipment and process in more detail.Then,taking the shaft test bed of DUT as an example,the effect of the change of the equivalent fulcrum position of the bearing behind the stern tube on the bearing load is analyzed,the feasibility of calculating the equivalent fulcrum position of the bearing behind the stern tube using distributed support is verified,and the conclusion is concluded Non-linear relationship between changes in bearing height and changes in bearing load.Finally,taking the 176000 DWT bulk carrier as an example,combining the relevant standards and regulations,considering the impact of hull deformation,the shafting is calculated undertwo conditions of linear and non-linear changes,and the results are compared and analyzed to determine the characteristics of different calculation methods.