Architecture And Integration Of Life-cycle Safety Guarantee System Of Structures

Safety of structures is a common and important problem in the mechanical engineering. Recent years there is a trend of developing unified theory of fatigue and fracture to describe the life-cycle damage behaviour of structures. Researches on safety guarantee are going toward multi-method synthesis, system micromation, network availability and life-cycle information management. It concers with cross research problems on many disciplines to develop the life-cycle safety guarantee system. With the breakthrough of micro-machining technology, smaller gap between components can be manufactured. Physical effects which are negligible in the characteristics of larger scale structures and devices will take import roles in the deep micro word. Problems related to the above topics have been researched and discussed in this dissertation. The main contents of the dissertation are presented as follows:1. More agreements will be obtained for prediction of structural fatigue life if the difference between the experimental loads and the in-service loads can be considered adequately. Structural life-index technology is developed as a simple implementation of the life-cycle safety guarantee system. Life-index unit monitors the in-service loads by sensors, calculates the damage and predicts the remaining life of structures. Field-bus interface is integrated into the unit so that a distributed life-index area network for large structures is available. In addition, several signal amplifiers needed in the life-index unit are designed.2. CAN (Controller Area network) is famous for its excellent real-time ability and high performance to cost ratio. CAN is a typical event-triggered field-bus, and CAN applications exhibit low bandwidth utilization ratio. A time-triggered scheduling method for the CAN 2.0 has been presented by use of hardware periodical interrupt of micro-controller and software programming technique. The results of the evaluation experiments for bandwidth utilization and message error ratio show that time-triggered application and very high bandwidth utilization can be achieved with CAN 2.0 bus under the help of hardware periodical interrupt of micro-controller. The method is suitable for applications in which a lot of periodical data exchanges and a few of non-periodical messages are required, such as distributed data acquisition system.