Research On Product Safety Criticl Degree

Safety is one of the key performances of product. During the designing and developing processes, because of the safety design is restricted by economic cost and developing time, making safety design equally to each component is impossible for practical purposes. The component which plays an important role to the safety should be priority of design. In order to quantitatively describe the component's contribution to product safety, the conception of "safety critical degree" is put forward in this paper. The product's entirety safety will be improved through the inherent safety design carrying out on the components which have large critical degree.Denoting and ascertaining the safety critical degree is the key step of the researching in this paper. The accidents which only results from fault is the objective researched in this paper, therefore, fault which links the safety and reliability is the point of penetration in this paper. After profoundly understand the scientific conception of system safety, this paper structures two indexes to describe the safety critical degree: compromise degree and critical degree coefficient.Surrounding the above-mentioned train of thought, this paper establishes a product hierarchical structure model. Fuzzy comprehensive evaluation is used to quantitatively calculate the compromise degree and the fuzzy fault tree is applied to calculate the coefficient of critical degree. Then thorough analyzing the relation between these two indexes, AHP is used to amend the index with weighted value. And then, according to the evaluation to many indexes, composes the indexes with weighted average law of geometry, we get the safety critical degree numerical value of component.Finally, car's brake system is cited to validate the quantitative model founded in this paper.