Study On Load Identification And Experiments In Time Domain

With the regulation for the control of ship noise more and more strict,the vibration,which is the primary excitation source of ships,has been drawing more and more attention.Identifying the excitation characteristics of the machine accurately plays an important role in developing Green Shipping and sailing safety.Firstly,a brief review of time domain and frequency domain method is given.Various scientific researches have been carried out for the beam and the shaft structure upon the utilization of the least mean square(LMS)method.The procedure for the application of the time-domain force identification method has been briefly reviewed in this dissertation.Force Equivalence was proposed to overcome the shortage of traditional method applied to engineering practice.An experimental bench was established and the accuracy on different occasions has been evaluated.It has been realized that the measurement of the inner excitation directly by sensors is hard to perform,and the error between original and equivalent forced responses is utilized to evaluate the accuracy of identified load.The response error is then identified to be an effective parameter on the experimental system under a serial of conditions with various quantities of the excitation points and response points involved.Finally,the LMS method has been extended from single direction to multiple directions.Based on the analysis of numerical results of a single-layer vibration isolator system and the experimental results of a double-layer vibration isolator system,the loading condition of the system can be identified.Furthermore,the accuracy and feasibility of the method have been validated.