Abstract: For the problem of uncertainty of work life distribution and difficulty in predicting demands for life-limited spares, a determination method of support plan for life-limited spares is proposed based on Normal-equivalence. At first, work life of life-limited spares is equivalent to Normal distribution based on Bayesian theory in order to calculating the numbers of spares demand; Then life replacement probability is put forward to measure the safety benefits during the replacement cycle; Finally, the optimal replacement cycle is obtained by tradeoff between safety benefits and economic costs so that the support plan is also got. Compared with simulation results, the examples show that our method is reasonable and feasible and owns high precision.

Key words: Normal distribution, life-limited spares, spares demand, replacement cycle, support plan