Study on Inefficient Factors and Storage Reliability for the Antiaircraft Missile

In the paper, the antiaircraft missile is assumed as the researched object, and its inefficient factors and storage reliability is focused to be analyzed. The weaknesses of storage of the antiaircraft missile could be confirmed with its inefficient factors analysis of storage, reliability analysis of storage and reliability assessment of storage. So it is may be easy for operational personnel to take effective measures to improve conditions of storage and usage of the antiaircraft missile and extend its life; The results of the paper may not only be data support for making codes of the rational use of the antiaircraft missile, maintenance measures and etc. but also be guidance for life-extension repairing work of the antiaircraft missile, effective usage of resources, reducing the use of maintenance costs. Analysis of Inefficient Factors of Storage of the Antiaircraft Missile Storage reliability is usually defined as "the ability of equipment under the specified storage conditions to maintain a required function within a specified storage time." The trait of usage for an antiaircraft missile (it will briefly be called the missile in under lines.) is long-term storage and one-shot firing. In order to ensure the missile always to be in good condition within long-term storage, the missile is needed periodic inspection and test, repairing on time if there are problems. Transport, mounding, duty, power-on training and other tasks are possible during life cycle of the missile. Therefore, factors affecting reliability and longevity of the missile storage include natural factors and human factors. Natural factors mainly refer to the missile storage environment temperature, humidity conditions; human factors mainly refer to missile transport, mechanical vibration or shock of mounding, power-on training and electrical shock during testing process. After a period of storage, transport, mounding, power-on testing, fault repairing and other operations, electrical components inside the missile would be occurred parameters over proof, and mechanical parts inside the missile would be occurred wear, corrosion, and plastic rubber elements would appear brittle, aging etc. These phenomena caused by natural and human factors would generate degrading of reliability the missile storage or shortening the life of the missile . The missile is constructed by various subsystems or modules, long-term storage has different effects on missile accessories , Storage has little affect for reliability of some accessories, for example, pieces of metal structures; others components, such as seals, charge and missile batteries, there would be performance changes, or even failure; some electrical components required high parameters would generate parameter shift, even be over range of technical requirements or cause fault for long-term storage. By means of statistical data of maintenance and life-extension maintenance test of one antiaircraft missile, which is exceeded its design service time, main performance changes of the missile under long-term storage conditions include:(1) The metal parts wear, rust, and corrode. Corrosion or rust of cabin, rudders, wings or other alloys, and other metal parts mainly affect their normal performance; contact oxidation due to corrosion would induce poor conductivity. (2) Aging deterioration of the non-metallic parts. Various degrees of deterioration of aging and dry exist in different rubbers, sponge mats, seals, greases and, affecting the seal elastomers and components, resulting in leaks, oil spills, and some mechanics does not work properly due to poor lubrication. (3) Parameters are over proof. With growth of storage or usage 4th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2016) © 2016. The authors Published by Atlantis Press 1465 time, onboard instruments of missile and electrical equipment would gradually generate parameters drift, sensitivity decreased, poor symmetry of parameters, waveform distortion and so on. (4) Degradation of pyrotechnic performance. Deformation, cracking, out sticking and other phenomena caused by long-term storage of engine charge and its cladding layer, insulating layer, liner, would make performance of engine charge, electric squib, start blasting detonators and explosive bolts to decline. (5) Human injuries during operation or maintenance due to improper usage. Human injuries includes pressure, touch, scratch in loading and unloading process, and other damage, for example, components damage, socket and pin damage, are caused by non-standard operations while performing detection and maintenance. Analysis on reliability of missile storage By means of statistical data of maintenance, life-extension maintenance test and shooting practice of one antiaircraft missile which is exceeded its design service time, the reliability of missile storage could be analyzed. Long-term storage has different impact on modules, maintainability of various components are not exactly same. So missile modules could be divided into four categories to be studied : The first category has extremely high reliability, long-term storage has little impact to them, or their storage life are much longer than other missile modules; second category is available for regular testing, and they could be repaired when fault are detected, or they could be replaced with spare components; the third category isn’t available for regular testing, but their change trend of performance parameters could be forecasted; The fourth category is relatively short shelf-life or easily be regularly replaced in order to meet the required reliability of missile storage. Through analysis on reliability of components storage of missile, the components which are easily damaged can be found. Storage Reliability of the First Class Modules. The first class modules include airframe structure, shipping launchers, missile cable network, warhead, detonator, explosive bolts. According to the resume of a missile and maintenance records, the modules almost haven’t inefficient phenomena. In the case of warhead, all of warheads not only have internal metal parts, but also non-metallic parts, and have chemical composition requirements as well as structural parameters. There are two ways to determine life of a warhead, one is assessment on whether performances of a warhead has significantly worse; the other is to consider security of a warhead service process. The conclusion for sub-sample of detection and test of long-term storage of one warhead is shown as table 1. Combined results from detection and test based on study samples and extended sample of subject of a warhead, the conclusion could be affirmed: after warhead is loaded and to be stored by the form of barrel bomb under specified storage conditions, it could keep its operational performance without maintenance during its expected life. Storage Reliability of the Second Class Modules. The second modules include remote control answering machine, autopilot, fuse electronics, converter etc. Such components are key components to achieve missile capabilities. They usually have a complex structure, circuits with high sensitivity and high failure rate, and generally need to be tested for its main performance parameters in periodic maintenance. Let’s see fuse. Fuse is a sort of photoelectric product, constituted by the optical system, one sensor, electrical circuit etc. Similarly, storage reliability of fuse could be broken down into storage reliability of three previous parts. The conclusion for sub-sample of detection and test of long-term storage of a fuse is shown as table 2. Regular tests are conducted for electrical parts of fuse; the faulty component in tests is electrical circuit. Therefore the discussion on storage reliability of fuse as a second class member is focused on its electrical portfolio. According to the conclusions, optical parts could be found to have high reliability, whose sub-sample function after long-term storage has not significantly decreased, and therefore could be treated as a first class component; and one sensor due to unavoidable liquid leak problems, and the leak rate is almost substantial linear, so the liquid leak rate would determine the storage life of the sensor, thus affecting the overall life of the fuse and missile. Storage Reliability of the Third Class Modules. The third class modules include engines and charge, detector of fuse. The components couldn’t regularly be tested, but relevant studies have