Vibration Analysis Of Thick Cylinder Shell And Research And Application On Damping Effect

Submarine is an important part of conventional naval forces, because of its superhidden so that the submarine has a special deterrent effect, but noise of the submarineassembly to increase their chance of being discovered, So their survival is threatened.Study shows that the vibration generated by transmission device when it worksaccounts for most of the submarine noise radiated sound field. This vibrationtransmitted through the device to the hull, causes the vibration of the hull, thus radiatesnoise to the flow field. This article focuses on the theory of thick shell vibration and therole of damping technology in the thick shell vibration and acoustic radiation field.Analyze the Three-dimensional stress state of any cell in thick shell with thecylindrical coordinate system. Consider the force variation in the thickness direction,derive motion equations and state equations of any point in the thick shell based onelastic mechanics and wave mechanics knowledge. According to the boundaryconditions to solve modal parameters, provide a theoretical basis for the prediction forvibration of thick shell.Starting with damping material mechanism analysis, based on the finite elementmethod, calculate top ten modal damping ratio of the shell with free damping layer andconstrained damping layer respectively. Obtain the influence of various parameters onthe hole shell vibration.Compared the characteristics of commonly indicators to measure the dampingeffect, take vibration level as objective, take various factors as design variables, tooptimize the infinitely long "sandwich" structure with constrained damping layer; Forthe finite length shell, use structure with variable cross-section and damping to suppressaxial vibration.Analyze of the actual submarine modal; Analyze of the plate contribution of Soundpressure; use the unit acceleration to simulate vibration excitation, research the radiationacoustic of submarine, Contrast the sound pressure of same point and same soundsource with two different attributes, draw the role of damping in reducing the soundpressure.Through theoretical analysis and simulation comparative analysis, we can see thedamping approach is very effective in suppressing the vibration of thick shell, bysuppressing the vibration of thick shell thereby reducing the submarine acoustic field isdesirable.