Hemodynamic Analysis And Optimal Design Of Coronary Stent

With the continuous development of domestic high-speed railways over recent years,people are demanding more on their security.The operational stability of bearings has direct influence on the security of trains as one of the major components of high-speed trains.Scientific and objective detection of bearings serve as one of the important means of guaranteeing their working conditions,while comprehensive and reliable information about bearings from reasonably-placed sensors on them can be a valid and available premise of such detection.This paper conducts a research on the acquisition of parameters and index about the axle box's modality,selection of the optimal amount of the modality and sensor placement in terms of optimal sensor placement of bearing boxes.More detailed descriptions are presented as follow:First of all,this paper solves the modality of prestress of the bearing box based on finite element method.Against detailed features of the bearing box causing unqualified segmentations of grids,this paper simplifies the model and improve the quality of its grids through grid control.As for the different modal shapes from traditional free modal analysis and actual processing,the paper uses prestress modal analysis to produce input of modal shape for follow-up analysis of acceleration sensor placement when solving the modal shape.Secondly,this paper comes up with the method of ascertaining optimal targeted mode numbers based on DRS-fisher information matrix.Against imprecise and nonobjective targeted mode numbers through arbitrary selection,the paper adopts DRSfisher information matrix containing more information than fisher information matrix as the optimal mode numbers to confirm input messages and calculates information entropy,selects optimal targeted mode numbers in accordance with discontinuous points and verifies the difference made by this method through the contrast between the effects of simulation experiments.Next,this paper also sheds light on improved EI progressive reduction of sensor placement.Against the difficulty during the selection of the scenario about initial measuring points when aiming MAC nondiagonal elements as the target value,the paper adopts singular value decomposition(SVD)to narrow down the scope of measuring points,while EI progressive reduction is adopted after which to select an initial scenario and update measuring points recurrently.After contrasted the effect of this method with the other two similar ones through simulation experiments,it is proven that the information of measuring points from this new method has more comprehensiveness.Finally,this paper finishes the proofreading.The paper extracts the bearings of inner race defect and rolling element defect respectively,then extracts the vibration signals of measuring points in the scenario through multibody dynamics simulation of the bearing and bearing box on the basis of Adams and conducts fault diagnosis.As a consequence of the simulation,the sensor placement in this scenario is more scientific than that in traditional one through collecting signals.