The Estimation Method Research On Exciting Force Of Equipment To Ship Structure

For the study of the noise and vibration of the warship focused on three main areas:Noise and vibration input source of which is also called noise and vibration analysis, shipstructure vibration system vibration transmission also called attenuation analysis, and thevibration output problem research. The analysis for the vibration noise source of the noise andvibration system haven’t been so much for a long time, where the vibration noise source hadbeen discussed during the analysis of system isolation effect, and the analysis of equipmentincentive load and ship structure coupling mechanism have been less more than it.On the time of noise and vibration prediction of ship structure, equipment incentive loadsas the input of the noise and vibration system have great value for the research of the sendingthe noise and vibration of energy, force output characteristics under different conditions, thecoupling characteristics of the installed base and noise, and the vibration prediction accuracy.Because of the correct data of equipment incentives load, ship structure vibration transmissionand noise radiation forecast can get much realer results. However, for the conventionalapparatus excitation load, the measure acceleration values given by a simple bench testequipment, as input load of noise prediction on ship structure have forcasted the noise. Butbecause of the strict coupling between the device excitation force and the ship installedbase, the equipment incentive loads will change as the installed base changes, then load inputnoise prediction in traditional equipment incentive has some error, and it will affect theaccuracy of the forecast value of the noise and vibration of the ship structure.In this paper, according to the above research, based on the theory of vibration, ananalysis model about the vibration of device coupled with installed base has been created, theformula of the device excitation force acted on the installed base, and the simplified methodof the same force acted on the hull structure have been obtained; and the correctness of themethod has been verified at last. The following aspects are included in this paper:1、 This model has been divided into more than one degree of freedom vibration system,through the simplification of “equipment-isolator-Equipment installed base”. Based onthe theory of vibration, a formula about the one-dimensional, two-dimensional andthree-dimensional model of equipment incentive loads acted on the hull structure, has been deduced meanwhile according to engineering practice, based on the free speed theory, andthe constant source characteristics of the device, the simplified method of coupled vibrationanalysis between device equipment and hull structure has been obtained, and the correctnessof the method has been verified the estimation methods. about incentives load acted on thehull structure has been formed initially2、 On the base of the constant device characteristics of the inner source, the endogenouscharacteristic parameters have been obtained first by the twice vibration test, second by thebasic convert of the test result. Then through creating the coupled vibration model about thedifferent unbalanced excitation force acted on the equipment and hull, the indirectmeasurement method of the device endogenous characteristics has been given.3、 For general type base, the combining circuit has been obtained according toadmittance power flow method, and the impedance estimation method of the simple basein the case of the low frequency has been derived; then for the mechanical properties of thelong seat pier base structure on the main hull structure of captain direction, according to theempirical formula, the engineering estimation methods about input mechanical impedancehave been researched and got at different frequency.4、 Equipment exciting force estimation methods in this paper will be used on doublecylindrical shell for noise and vibration prediction,which focuses on solving the input noiseprediction problem and through the estimation of the equipment incentive load, the equipmentmodel will be simplified during the noise prediction,in order to ensure the calculationaccuracy, and at the same time to improve computational efficiency.