Research On Reliability Modeling And Prediction Of Small 256 Ultrasonic Phased Array Instrument Mainboard

As a very important test equipment in the field of non-destructive testing,ultrasonic phased array instruments have complex structures and it is of great significance to study their reliability problems.Titled as“research on reliability modeling and prediction of small 256 ultrasonic phased array instrument mainboard”,this paper starts with the framework of the ultrasonic phased array instrument mainboard,and focuses on the theoretical methods and implementation skills of instrument mainboard reliability modeling,reliability allocation,reliability prediction,and reliability test which have been applied to the development of ultrasonic phased array instrument.The dissertation has important academic value and practical significance for improving the level of non-destructive testing technology and instrumentation and promoting the development of intelligent manufacturing technology.The research work is supported by the national special scientific instruments and equipment development project“new type ultrasonic phased array instrument development and application”?No.2013YQ230575?.We are doing research into the reliability modeling and prediction theory of small 256ultrasonic phased array instrument mainboard.The dissertation summarizes domestic and foreign research progresses,including the theory of instrument reliability modeling and instrument reliability prediction.The main work and contribution on this dissertation can be summarized as follows:?1?Study the reliability modeling method of small 256 ultrasonic phased array instrument mainboard.This paper introduces the basic structure of small 256 ultrasonic phased array instrument mainboard,divides the state of the instrument mainboard,establishes a 4-state Markov model diagram of the instrument mainboard,lists the state transfer equations according to the Markov model diagram,and then obtains the status of the instrument mainboard by solving the equations.With the probability of remaining and steady state availability,the theoretical modelling and derivation of the instrument mainboard Markov model is completed.Finally,the steady state usability of the calculation example is solved by Matlab simulation.?2?Study he reliability allocation method of small 256 ultrasonic phased array instrument mainboard.A method of reliability allocation of ultrasonic phased array instruments based on fuzzy analytic hierarchy process is proposed by integrating triangular fuzzy numbers and analytic hierarchy process.From the top down,relevant factors concerning reliability allocation are decomposed into target layer,criterion layer,and object layer.At the same level,a schematic diagram of the Fuzzy Analytic Hierarchy Process?AHP?structural model of the instrument mainboard is established.Based on expert evaluations,the corresponding fuzzy weights of each influencing factor at the criterion level are determined.At the same time,the fuzzy evaluation of each module of the object layer relative to the impact factors of the criterion layer is given.Set the degree of membership to convert it into a fuzzy range,and then introduce the optimism index into further non-fuzzy numbers.Finally,the weight of each module reliability index is obtained,and the overall reliability index of the instrument mainboard is allocated to each module.?3?Research on reliability prediction of small 256 ultrasound phased array instrument mainboard.Based on the reliability prediction method of component stress analysis in the GJB/Z 299C-2006"Electrical Equipment Reliability Prediction Manual",the reliability prediction of the instrument mainboard is completed.The actual failure rate of each module of the instrument mainboard is calculated,and the actual failure of the instrument mainboard is obtained.Then converted the actual failure of the instrument mainboard?_A=2.914×10^-4/h into mean time between failure MTBFA=1/?A=3431.7 h>1800 h.It can be seen that the reliability of the instrument mainboard designed according to the component selection can meet the development requirements.?4?Research on reliability test of small 256 ultrasonic phased array instrument mainboard.Combined with the actual situation of small 256 ultrasonic phased array instrument mainboard,based on GB/T 15214-2008"Ultrasonic Diagnostic Equipment Reliability Test Requirements and Methods",the reliability qualification test program of the instrument mainboard is designed in detail.Select the timing cut-off test scheme 5:9,select the instrument mainboard test sample5 sets from the sample recommendation table,determine the test stress,test equipment,failure classification and criteria,and finally develop the instrument mainboard reliability qualification test procedure.The instrument mainboard reliability test results show that the actual reliability of the instrument mainboard meets the index requirements.The reliability modelling and prediction theory of small 256 ultrasonic phased array instruments studied in this thesis has been applied in the development of ultrasonic phased array instruments.The results show that the reliability of the instrument mainboard meets the expected design requirements,which verifies the feasibility,effectiveness and correctness of the research content of this dissertation.