Research On Calculation Method Of Ship’s Propulsion Shaft Shock Response Under The Underwater Non-Contact Explosion

The ship’s propulsion shaft system is one of the most important parts of the ship’s power plant.Its impact resistance ability directly affects whether the ship can maintain normal operation and combat capability when it is exposed to underwater non-contact explosion.However,due to the harsh conditions for carrying out real ship experiments,huge cost,and low success rate,our country does not have the conditions to conduct large-scale experiments.This paper studies the calculation method of the anti-shock performance of the ship’s propulsion shaft system,and calculates the shock response of the complex shaft system structure of small ships under non-contact explosion.Firstly,the paper introduces the physical process of underwater explosion,the basic theory of coupled acoustic-structural analysis and the related theory of dynamics calculation And he principles of modeling methods and equation solving methods commonly used in the analysis of shafting impact response are briefly introduced,and their advantages and disadvantages and the main application calculation fields Then,the paper briefly introduces the development history and basic concepts of the discrete-time transfer matrix method of multi-body system adopted in Chapter 3.Finally,based on the experimental data and the finite element model,the correctness of the structure response under underwater explosion load calculated by the acoustic-solid coupling algorithm is verified.Secondly,based on the discrete-time transfer matrix method of the multi-body system,the paper models the small-sized shaft system including the coupling part,then derives the transfer matrix forms of its typical components,and the entire system’s transfer matrix equations.The static deflection of the shaft system with or without elastic support,as well as the motion characteristics and deflection response under the fixed hinge boundary are calculated,and then the boundary is changed to the movable and elastic hinge boundary conditions to obtain the motion characteristics of each component of the shaft system.Then use Abaqus to model the shafting-ship coupling structure based the solid element,including the propulsion shafting,the main engine mechanism and the cabin section,and then define the contact and connection between the parts.Based on the coupled acoustic-structural analysis,the paper studies the impact dynamic response of the shafting structure under various working conditions,and the stress transfer and acceleration response characteristics of the interface between the ship and the shafting,the paper also analyses the stress and acceleration response of typical components on the shafting.Its changes with time and peak characteristics,and other responses such as the rotation angle of the universal coupling are calculated.Finally,the shock response spectrum and non-integrated calculation method are used to study the shock response of the shaft system,and the structure of the bearing seat is optimized.The paper establishes the non-integrated model of the shaft system is established based on the beam element and the three-dimensional solid element,and extracts the impact environment at the installation position of the shaft system on the ship,then converts its into the negative triangle wave load and input the non-integrated model.The stress characteristics of the typical position of the shaft system are calculated,and the paper proposes the stress correction method because of the difference between the non-integrated and integrated calculation results,and verifies the correctness of it.Finally,by comparing the impact environment of the bearing seat panel,the structure of the bearing seat is optimized.