Reaserch On Safety Quantitative Model Of Electro-Mechanical Products

Electro-mechanical products have been widely used in our daily manufacture and life. However, with the development of technology, the technical composition of electro-mechanical products has been more complex and the safety of electro-mechanical products is facing great challenges.At the same time, product recalls as a severe risk have troubled manufacturer if the safety deficiencies of their products exist. So,how to quantify the safety of electro-mechanical products reasonably and characterize safety performance will be an important rule during the evaluation of product safety.In this thesis, quantitative indicators and methods of evaluation all around the world about electro-mechanical products'safety have been researched,which most based on type tests and reliability. Then,the defects of these methods are discussed. In light of the above study, a safety quantitative model of electro-mechanical products was established in this thesis which characterizating on the risk of accidents as the major input. On the one hand,based on the Accident Causes Theory of hazard state lead to product accidents, the model used system safety analysis to build the multi-state FTA to determine the risk of components and subsystems, combined with electro-mechanical products character. Then, according to Markov random theory, the probability of the accident and state transition on electro-mechanical products were quantified. Further, the probability of secondary accidents were researched. On the other hand, the random consequences of accidents were studied in this model, then improved FMECA to determine the severity of the accident. Ultimately, the safety of products was quantified by characterizating on the risk of accidents and the level of electro-mechanical products safety was denoted.In order to use of this model better,the model was expanded further in this thesis. According to the function of random process characteristics, a cross-covariance matrix of product system has been raised, which can help us determine the impact of the hazard states.It can provide a reference for accident prevention of electro-mechanical products.Then, the life time of product safety was advised,which can provide effective support to MTTB of product .