Study On Reliability Allocation Methods Based On Scrap Tire Crushing Recycling System

As the increasing growth of car ownerships, the number of scrap tires is rising rapidly at an alarming rate, which will enhance difficulty in recycling scrap tires, and will cause resource scrap as well as serious environment pollution with inappropriate disposing means. However, if being recyclied efficiently with fit methods, these scrap tires would be benifical to energy conservation, environmental protection and considerable economic benefits. The crushing and recycling system is the key hardware guarantee for recycle of scrap tires. Meanwhile, the product reliability, an important index to measure product quality, refers to the ability to finish expected task within specified time under specified conditions. Therefore, reasonable reliability allocation can ensure and improve the reliability of the key equipments in recycling process line for scrap tires, and is of theoretical research siginificance and application value, which is the key point to realize efficient dispose of scrap tires. In this work, three reliability allocation methods suitable for different suitiuations are presented, and are employed in three major equipments of recycling process line for scrap tires.Firstly, this work anslyzes the research status of reliability allocation methods and introduces three major equipments included in recycling process line, namely, shredder, granular and vibrating screen. Based on this, a new relablility allocation method for conceptual design stage is proposed. The method combines triangle fuzzy algorithm with the DEMATEL effectively, which accommodates to the characters in conceptual design state, in which some informations are difficult to quantity and many internal and external influence factors need to be balanced. The new method is applied in the design of shredder and the allocation plans obtained from new method and traditional method, respectively, are compared, which verifys superiority of the new allocation method. Secondly, another reliability allocation method for product family oriented modular design is presented in this work. According to the quantitative indexes, product is divided into basic module, flexible module and characteristic module. And then, combining with APH and expert evaluation method, this work presents this method for product family of modular design, in which module type, dynamic change in market demand etc. are regarded as influence factors. In this section, this method is used in the design for vibrating screen, which demonstrates the implementation steps of this method. Thirdly, based on factors of product life cycle, this work presents the third allocation method for detailed design stage of product. In order to obtain this allocation method, according to FMECA information of product, use fault degree of product is defined and life cycle of product is divided into 5 stages including design, manufacture, utilization, maintenance as well as scrap. And then, in matrix operation, sensitivity of cost, advancement of process, fault degree of utiliazation, maintenance cost and recoverability are selected as typical factors in five different design stages. This method is employed in reliability design of granular. Comparing the allocation plan obtained by new method with fuzzy allocation method, FAHP allocation method etc. 4 methods, and the reasonability of this is verified. Subsequently, reliability allocation plans for sub-system or sub-module of the whole recycling process line of scrap tires. And this work puts forward how to improve operation of manufacture system and realizes efficient work of staff, furtherly. Finally, a conclusion for achicvements of research is generized and future investigation direction is indicated.