Small Sample Maintenance Test And Evaluation Methods

The maintainability test and evaluation methods in our country are now only confined to the methods of GJB, in which the test quantum and criteria are determined. The tests are carried on according to the test quantum and the observations are used to demonstrate the achievements of weapon systems of the maintainability quantitative requirements specified in contracts, then the decision whether to accept them is made. The test quantum is generally small due to the extremely complexity of modern weapon systems, high expenses and long cycle of the tests, which makes the demonstration methods of GJB more difficult to be put into practice.In recent years, with the development of computer simulation, system modeling and W&A (verification, validation, and accreditation), we can carry on the tests in many aspects and ways to demonstrate the weapon systems' maintainability. Meanwhile, there is a large quantity of available information before tests, such as history information, subsystem information during research and development, information in different circumstances and phases, simulation information and expert information etc. If all the information can be fused properly, twice the result can be got with half the effort.In point of engineering, this paper improves on the method of GJB2072-94-1-A on the background of "XX Missile Weapon System Maintainability Test and Evaluation", and provides the new method based on Bayes theory to demonstrate MTTR (mean time to repair) of weapon systems. It studies the determination of population distribution, information fusion of multiple sources based on evidence theory, the consistency of prior information relative to field test information and the robustness of prior distribution. With the new methods provided, only a small number of samples are required at the same risks, so the test expenses and test time are reduced. Now the method has been adopted in the scheme of "XX Missile Weapon System Maintainability Test and Evaluation".Finally, the maintainability demonstration on "XX Missile Weapon System" is conducted and the results are analyzed.