The Research Of Reliability Evaluation Method And Experimental For The Deep Diving Outboard Valve

The experiment is conducted on a manual and electric deep diving outboard valve to present an optimized assessment method of its reliability.Considering the existence of the easy fault link on the valve under its working stress,the assessment method is adopted to assess the easy fault link and the rest non-fault parts during the experiment,respectively.Then the reliability test system of the deep diving out board valve is designed and the reliability and the reliability life of the valve are analyzed based on the obtained data.Due to the weak links of the deep diving out board valve,which contributes to all the failures of the construction during its working lifetime test,an assessment method including a separation of the easy fault link from the integral construction is presented to assess the easy fault link and the rest parts separately.Then a synthetic assessment mode of the reliability is obtained.The structure of the deep diving outboard valve is analyzed through methods of fluid simulation,site testing and structure simulation and the stress condition of the valve stem is obtained.Then the easy fault link with small safety coefficient is targeted,which is the sealing surface.The failure mechanism of the easy fault link is analyzed,and results show a big shape parameter of the experimental data under Weibull distribution.In order to improve the estimation precision of the distributed parameters under Weibull distribution with large shape parameter,an estimation method involving the genetic algorithm based on D inspection is presented after considering the interval characteristics of parameter estimation and general test methods for similar distribution pattern comprehensively.Moreover,the estimation precision and stability of the algorithm is investigated.Equations for reliability value and reliability life are given based on the method of optimal confidence limit on the condition that there is no failure data under the same time censored condition.The influence of the parameter evaluation errors come from the experiment data and shape parameters of the old valves to the lifetime estimation of the presented valve is analyzed.The parameters selecting approach for the reliability test based on method of optimal confidence limits is presented.On the basis of this method,a shape parameter value method is proposed based on the relationship between the test results and theacceptance condition and a synthesis method of the life reliability of the deep diving outboard valve is discussed.In order to calculate the reliability value and reliability life of the deep diving outboard valve,the reliability test system is designed and the experiment is completed on the basis.With reference to the relative national standards and the features of the deep diving outboard valve,static opening and closing test system,mechanical environment test system,salt spray test system of the deep diving outboard valve are designed,testing methods are made and the fault statistics principles are confirmed.The obtained data is used to verify the prediction on the valve's fault mode and data distribution mentioned previously.Then,the abnormal test data and the distribution pattern of the reliability test are analyzed to testify the validity of the inference for the data distribution of valve's easy fault link.The “easy fault segment separation method in reliability assessment” is adopted and the relevant reliability data is analyzed to evaluate if the deep diving outboard valve can meet the requirements.Further,MATLAB GUI is adopted to design the “deep diving outboard valve reliability evaluation system” to facilitate the application of the reliability estimation methods.