Error Analysis Of Ship Propulsion Shaft Load Test Of Large Ships

As the construction of ships continues to develop in the direction of large-scale,intelligent and refined,the construction period of ships is becoming shorter and shorter,and the requirements are getting higher and higher.After the completion of the shipbuilding,most of the shipyards used a reasonable alignment process to install the shafting system.For the quality of the shafting alignment,it needs to be tested by bearing load test technology.Under the premise of ensuring the construction process,it is the focus of this paper to measure the more accurate bearing load and maximize the quality of the shafting alignment.First,theoretical analysis of the resistance strain gauge method is used to derive a formula that can reduce the test error.Based on the theoretical error analysis,the design experiment was carried out on the ship propulsion shafting comprehensive experimental platform to verify the principle of the piece and the film selection method.According to the experimental results,the correctness of the theoretical error analysis is verified,which has certain guiding significance for the real ship test of the resistance strain gauge method.Secondly,for the theoretical analysis of the topping method,the jacking coefficient under two different definitions is explored.Based on the finite element modeling analysis of the ship propulsion shafting comprehensive experimental platform,the variation law of the jacking coefficient at different positions is explored,and the digital topping test system is used to explore the variation law of the jacking load at different positions..Through the jacking coefficient and the jacking load at different positions,the test values of the bearing load at different positions are calculated,and then compared with the true value of the bearing load to obtain the error law of the bearing load at different positions.Finally,as ships continue to move toward larger sizes,their shafting sizes are also growing,especially for some ships.In the harsh working environment,it will cause large deformation of the shafting.In this case,the reasonable alignment method of the shaft system processed according to the linear change can not meet the requirements of the bearing load calculation.When calculating the shafting system,an important factor affecting the bearing load calculation is the load influence number.Based on the ABAQUS software,this paper investigates the bearing load influence number of a certain 180,000 DWT bulk carrier shaft system under different deformation degrees under nonlinear conditions.The law of change,the concept of load influence function and load influence function matrix is proposed,and the axial alignment model is improved,so that the load of bearing under different deformation can be calculated more accurately,which provides a basis for more reasonable alignment of the shaft system.