Mechanical System Reliability Allocation and Optimization and Software Development
|Course||Mechanical Design and Theory|
|Keywords||Cost function reliability optimal allocation CCF(common cause failure) Visual C++|
The reliability allocation is one of the most important parts of system reliability design. It distributes the system reliability to all the components of the system quantitatively in accordance with certain criteria, eventually making the whole system reliability object assign to each subsystem or each unit. It can be used to guide the development of new product or subsystem and meets the customers’need.This paper expounds the status and development trend of the methods about reliability allocation of mechanical systems at home and abroad, and compares the advantages and disadvantages of every allocation method and application area. For the reliability allocation of complex mechanical system with each part of system independent, this paper focuses on the importance, technology maturity, standardization and maintainability of every part to propose a cost function model. And it builds a non-linear programming model based on total cost minimization, and solves the non-linear programming problem by Lagrange multiplier method, gets the allocation value of each part of system. The distribution of stress and strength of each part from system are assumed to be normal distribution, and the averageμs and standard deviationσs of stress distribution have also been known in the paper, together with the variation coefficient(σs/μs= C) of strength distribution. So it can get the two parameters:namely the averageμs and standard deviationσs of strength distribution through the stress and strength interference model of part. Then considering common cause failure, this paper uses the stress and strength interference model of system level to calculate the system reliability, and compares it with the objective reliability. After that it operates the reliability allocation using cost minimization method again, in order to get the optimal value of reliability allocation of each part of the mechanical system.Through the object-oriented technology of programming, this paper develops this mutual software of mechanical system reliability allocation based on Visual C++ 6.0. This software includes four modules:basic parameters input of parts, analysis and calculation, result data showing and result data saving. This software completes the visualizing and mutual operation and it has many merits such as having complete function, having good feedback.