Research On Methods Of Realiability Assessment With Small Sample For Water Ramjet

The reliability is an important index in the water ramjet. At present, the study of water ramjet engine is in its infancy. The experimental information with small sample characteristics is appeared. So, this article tackles the technology challenges of small sample reliability assessment from the point of view of the information discovery and information utilization. It is best for shorting the development and test cycles ultimately.The working characteristics of the various components in water ramjet and its reliability logical relationship are analyzed. The methods of the reliability assessment are discussed based on the prior information by studying the information and data characteristics of the water ramjet reliability. And the engine reliability assignment methods and test methods to determine the amount in early stage are studied.For getting the water ramjet reliability simulation information, the methods of acquainting reliability simulation information based on random factors and non-probabilistic factors are discussed. A reliability analysis method is presented using the representative points set of multivariate distribution as random variable set based on number-theoretic. The problem of interval reliability analysis is solved with the Kriging model and the response face model. And the reliability of two important parts, the grain structure with viscoelastic mechanical characteristics and the seal structure, of the engine are analyzed successfully. This provides a foundation for reliability information extraction and utilization.For the application of simulation information in the water ramjet reliability assessment, a reliability estimation method called inverse Bayesian method is presented based on stress-strength interference theory. In this Bayesian estimator method, filed experiment information with binomial distribution is regarded as prior information and simulation information is regarded as posterior information. The performance data appears dynamic characteristics by analyzing water pipe model and interior ballistic performance model. And compatibility and reliability assessment methods of he dynamic data with time series are analyzed.For the application of similar information in the water ramjet reliability assessment, a method of environment factor with simulation results is presented based on stress-strength interference theory. Compared to conventional environmental factor, the result of this one is more accurate and credible. Then, a reliability assessment methods using similar information is presented for the application of the similar information of non-probabilistic relevant different types of products.Whereafter, the application of AMSAA-BISE model based on instant modification strategies and a fuzzy Dirichlet distribution reliability-growth model based on stayed modification strategies is studied for the water ramjet reliability assessment. And, the application of the different model similar engine information and the expert information is discussed in the reliability growth model.Finally, the failure modes of the water ramjet at present stage are summarized. The system reliability assessment of the series model and the complex model is discussed. And the assessment method of system reliability based on component reliability estimation is studied.