Abstract

We consider a stochastically deteriorating system with self-announcing failures that require immediate reactive replacement. For such a system, we consider an age-replacement policy (without minimal repair) under which the system is replaced at failure (reactive replacement) or at a prescribed replacement time (preventive replacement), whichever occurs first. Motivated by factors such as decreasing salvage value or increasing costs associated with obtaining spare parts, we assume that replacement costs are non-decreasing in system age. We formulate a long-run expected cost-rate minimization model with instantaneous replacements that captures this dependency, and provide conditions under which there exists a unique optimal solution. We provide analytical and numerical results that compare the cost-rate minimizing optimal replacement policy, and its performance, to those for the case in which replacement costs are assumed to be constant. Finally, we also consider non-instantaneous replacements, and compare cost-rate minimizing and availability maximizing policies.

摘要

我们考虑具有自我宣布故障的随机恶化系统，需要立即进行反应性更换。对于这样的系统，我们考虑了更换年龄的政策（无最小限度的维修），根据该政策，系统将在故障（反应性更换）或规定的更换时间（预防性更换）时进行更换，以先到者为准。受诸如降低残值或增加与获取备件相关的成本之类的因素的驱使，我们假设更换成本在系统寿命方面并未降低。我们制定了一个具有瞬时替换的长期预期成本率最小化模型，该模型捕获了这种依赖性，并提供了存在唯一最优解决方案的条件。我们提供分析和数值结果，以比较将成本率降至最低的最佳更换政策的成本，以及其性能，与假定重置成本不变的情况下的性能相同。最后，我们还考虑了非即时替换，并比较了成本率最小化和可用性最大化策略。