Joint Maintenance Policies for a Stored System with Two Units

摘要

Failure of a stored system can only be detected after inspection and its reliability can be resumed by replacement of failed components. A maintenance policy of combining periodic inspection and preventive replacement is proposed to improve its availability. To coordinate component replacement and spare provision,an ordering policy of (0,1) is considered jointly. Thus,the joint maintenance policy contains inspection,replacement and spare provision. A programming model based on the joint maintenance policy is established,whose objective function is average expected cost,containing maintenance cost and inventory cost,and the constraint is system availability. Applying renewal theorem,the performance indexes are deduced under the condition that the stored system obeys the common life distribution. Numerical examples are given for a stored system with two different units,where unit 1 probability degrades with time and unit 2 probability degrades at each test. The effect of reliability parameters on the policies is discussed. The results indicate that the joint policy is very close to the independent policy.