基于两类失效的产品保修策略与出保维修优化

基于消费者对保修的需求,设计消费者偏爱的保修策略是制造商巩固市场地位、提升市场竞争力的一种战略决策。与此同时,以较低费用制定较长出保服役时间的出保维修策略也是消费者一直追求的目标。本文以两类失效产品为研究对象,首先从制造商角度将消费者偏爱的更新免费更换保修策略与产品定价相融合,开展了产品保修策略设计。其次,从消费者角度将预防维修与经典周期更换策略相融合,提出了维修—周期更换策略,且将其作为出保维修策略并对相应的性能进行了说明。通过数值实验发现,利润模型可对保修开展设计;与总费用模型作为目标函数相比,费用率模型作为目标函数可降低寿命周期费用;与经典周期更换策略相比,提出的维修—周期更换策略能使出保服役时间更长、费用率更低。     

预防性维修条件下产品保修策略优化研究

为了降低保修费用,对产品的二维预防性保修策略进行优化.将预防性维修对产品的维修程度进一步细分,并用修复因子来区别不同的维修程度,提出两种程度预防性维修相结合的保修策略.针对提出的保修策略,建立保修费用模型,提出模型求解方法.通过算例,证明该保修策略的有效性,并对结果进行了分析.     

有剩余保修时间阈值的可更新产品检测和预防更换建模与优化

基于两阶段的故障过程概念,对可更新保修产品,进行了有剩余保修时间阈值的周期检测和预防更换建模与优化。产品保修期分为两阶段：检测更换期和最小维修期。检测更换期开始于产品开始运行,当剩余保修期等于阈值时结束。最小维修期是检测更新期结束后直到保修服务终止的一段时间。在检测更换期,制造商进行等间距的周期性检测。如果检测发现产品处于缺陷状态或发生故障,将立即更换。在最小维修期,制造商为了降低服务成本,不实施检测和更换,对发生的故障只进行最小维修。从制造商角度出发,得到使单位时间内平均保修费用最小的剩余保修时间阈值和检测间隔。     

使用期内保修产品的最优更换策略

本文从消费者的角度出发,提出了在产品的有限使用期内,可免费维修保修的产品的更换策略.假设产品在使用期内可以更换一次,更换前后产品的故障率不发生变化.在保修期内,发生故障的产品的维修费用由生产商承担,消费者不用为此支付任何费用.在保修期外产品发生故障,消费者需要为此支付一笔固定的维修费用.然而,只要产品在使用,每发生一次故障都会对消费者产生一笔固定的停机费用.在这种维修计划下,产品的更换将分两种情况讨论:免费保修前和免费保修后.本文将建立两类最优更换模型,给出消费者期望支付费用的数学模型,继而求得最优的更换时间以及此时最小的支付费用.最后会给出模型的算例分析,给出在不同的保修期和有限使用期下,最优更换策略的相关特征.     

保修非更新产品检测和非完美视情维修建模与优化

针对退化服从两阶段故障过程的保修非更新产品，提出了有剩余保修时间阈值的非完美视情维修策略。在该策略下，产品保修期分为两阶段：检测预防维修期和最小维修期。在检测预防维修期内，针对检测时刻系统的状态(正常和缺陷)实施不同的维修策略。在最小维修期内，不进行检测，对发生的故障实施最小维修。以生产商承担的平均保修费用为目标函数，对检测间隔、预防维修水平及剩余保修时间阈值进行了联合优化。通过数值算例及对比分析验证了模型的有效性。     

按比例保修策略下多保修期差别定价研究

保修策略是联系厂商和顾客的一种合同责任,它往往用于促进产品的销售。产品保修期长短与其定价有着紧密的联系。本文在考虑一个厂商采用按比例保修策略及设定多个保修期的基础上,以产品的保修期和价格为决策变量,以厂商收益最大化为目标,研究了产品故障次数成指数分布下最优保修期和价格的组合策略,并通过算例比较了差别定价和单一定价下厂商的收益。最后,通过灵敏度分析,研究了消费者保修期偏移弹性对厂商收益所产生的影响。     

保修策略下的系统最优更换模型

本文研究了单部件组成系统的保修策略 ,提出了一种新的按比例保修和免费保修策略 .在假定故障部件不能“修复如新”的条件下 ,利用几何过程分别考察了顾客和商家关于产品的长期运行平均费用 ,求出了它们的明显表达式 ,并且可以通过数值法或分析法求出其最优保修期 .     

带保修期产品的预防维修建模分析

本文研究权衡了保修产品预防维修所节省的成本开支和同时增加的维修费用,以产品的长期平均成本率最低为决策依据,讨论了一个最优预防维修策略,给出了求解最优维修策略的有效算法.     

关于汽车追尾冲击模型的维修策略

讨论了关于汽车追尾的冲击模型的可修系统．在系统不能修复如新的条件下,假定汽车运行时间构成随机递减的几何过程,逐次追尾后的维修时间构成随机递增的几何过程．分别考虑汽车按比例保修和免费保修条件下,以汽车追尾次数N为策略,以车主在汽车长期运行单位时间内的期望费用为目标函数,导出目标函数的解析表达式P1（N）与P2（N）．最后,通过实例分析,求出最优策略N＊,使得车主在汽车长期运行单位时间内的期望费用最小．     

维修策略的概念、方法和模型（Ⅱ）

在维修更换策略的概念、方法和模型（Ⅰ）中给出了维修更换问题的建模方式，建模方法，本文继续给出关于维修更换策略的若干种常见的模型和进一步研究的问题。     

A general age-replacement model with minimal repair under renewing free-replacement warranty

A general age-replacement model in which incorporates minimal repair, planned and unplanned replacement, is considered in this paper for products under a renewing free-replacement warranty policy. For both warranted and non-warranted products, cost models from the user’s perspective are developed, and the corresponding optimal replacement ages are derived such that the long-run expected cost rate is minimized. The impacts of a product warranty on the optimal replacement model are investigated analytically. Furthermore, we show that the optimal replacement age for a warranted product is closer to the end of the warranty period than for a non-warranted product. Finally, numerical examples are given for illustration.     

Optimal maintenance strategy for non‐renewing replacement–repair warranty

In this paper, we study the maintenance policy following the expiration of the non‐renewing replacement–repair warranty (NRRW). For such purposes, we first define the non‐renewing free replacement–repair warranty and the non‐renewing pro rata replacement–repair warranty. Then the maintenance model following the expiration of the NRRW is discussed from the user's point of view. As the criterion to determine the optimal maintenance strategy, we formulate the expected cost rate per unit time from the user's perspective. All system maintenance costs incurred after the warranty is expired are paid by the user. Given the cost structures during the life cycle of the system, we determine the optimal maintenance period following the expiration of the NRRW. Finally, a few numerical examples are given for illustrative purposes. Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamic pricing and warranty policies for products with fixed lifetime

We consider a repairable product with known market entry and departure times. A warranty policy is offered with product purchase, under which a customer can have a failed item repaired free of charge in the warranty period. It is assumed that customers are heterogeneous in their risk attitudes toward uncertain repair costs incurred after the warranty expires. The objective is to determine a joint dynamic pricing and warranty policy for the lifetime of the product, which maximizes the manufacturer’s expected profit. In the first part of the analysis, we consider a linearly decreasing price function and a constant warranty length. We first study customers’ purchase patterns under several different pricing strategies by the manufacturer and then discuss the optimal pricing and warranty strategy. In the second part, we assume that the warranty length can be altered once during the product lifetime in developing a joint pricing and warranty policy. Numerical studies show that a dynamic warranty policy can significantly outperform a fixed-length warranty policy.     

Optimal periodic replacement policy for repairable products under free-repair warranty

This paper investigates the effects of a free-repair warranty on the periodic replacement policy for a repairable product. Cost models are developed for both a warranted and a non-warranted product, and the corresponding optimal periodic replacement policies are derived such that the long-run expected cost rate is minimized. For a product with an increasing failure rate function, structural properties of these optimal policies are obtained. By comparing these optimal policies, we show that the optimal replacement period for a warranted product should be adjusted toward the end of the warranty period. Finally, examples are given to numerically illustrate the impact of a product warranty on the optimal periodic replacement policy.     

Warranty cost analysis: Increasing warranty repair times

In this study, we model the warranty servicing costs under nonrenewing and renewing free repair warranties. We assume nonzero increasing repair times with the warranty cost depending on the length of the repair time. An increasing geometric process is used to model the consecutive repair times. We introduce the generalised alternating renewal process, which is an alternating process with cycles consisting of an item's operational time followed by the corresponding repair time. We derive analytical results for a generalised alternating renewal process with a finite time horizon and use them to evaluate the warranty costs over the warranty period and over the life cycle of the product under the nonrenewing free repair warranty and renewing free repair warranty. Properties of the model are demonstrated through a simulation study and through the application to warranty claims data from an automotive manufacturer.     

考虑维修时间的总质保需求预测模型

激烈的市场竞争迫使制造商们逐渐向以顾客需求为中心的公司转变。在近 20 年内,作为影响顾客满意度的主要因素,产品的质保服务管理的相关研究开始成为学术界的焦点。良好的质保服务会给企业节省较多的运营成本,故对于刚投入市场的新产品而言,准确地预测质保需求对制造商合理分配资金等具有重要意义。以往对质保需求的预测模型都局限于分析长期意义上一个产品的总质保成本,忽略了产品的维修时间和动态销售过程对准确预测产品的总质保需求及成本的影响。为此,以销售期内的产品所产生的维修需求为主要的研究对象,深入探讨维修时间对预测质保需求的影响。模型中,利用非齐次泊松过程模拟产品的动态销售过程,并利用复合随机过程中的交错更新理论来刻画维修时间对总质保需求的影响。最后的参数分析,为企业更好地管理质保服务提供了重要的现实依据。     

Repair-replace strategies for two-dimensional warranty policies

For repairable items sold with free replacement warranty, the actions available to the manufacturer to rectify failures under warranty are to

1. (1) repair the failed item or

2. (2) replace it with a new one.

A proper repair-replace strategy can reduce the expected cost of servicing the warranty. In this paper, we study repair-replace strategies for items sold with a two-dimensional free replacement warranty.     

Optimization of maintenance policy under warranty length‐based demand with consideration of both manufacturer and buyer satisfaction

This study proposes a model to optimize postsale services consisting of four factors: (a) the basic warranty length, (b) the extended warranty length, (c) the preventive maintenance level, and (d) the preventive maintenance interval. Furthermore, consumer demand for the product and extended warranty are considered as functions of the length of the basic warranty and extended warranty periods, respectively. Because buyer dissatisfaction with a product can lead to the loss of potential buyers and the switch of current customers to the competitors, both manufacturer and buyer satisfaction are considered in the model. Three comparative studies are done for showing the effectiveness of the model. The first one compares the results of simultaneous optimization from the two perspectives of manufacture and customer with the single‐objective optimization results from each of the mentioned viewpoints. The second comparison studies the provision of extended warranty contract in the proposed model, and the third comparison investigates the effect of preventive maintenance actions on the results of the model.     

新产品定价决策的影响因素分析

新产品的成功销售取决于两个重要的因素:一是具有生产特性的工程变量,比如产品的可靠性水平;一是具有市场特征的影响因素,比如价格和保障机制。为了实现收益,制造商必须认真审视价格、产品可靠性和保障机制的选择。因此,本文将价格作为外生变量,将保障机制与可靠性作为决策变量,建立了以最大化为目标的收益模型,分析可靠性与保障机制的最优策略。另外,探讨当不同变量的敏感性参数发生变化时,最优保障机制与产品可靠性的变化规律。最后,通过算例分析收益函数的基本特性,结论显示消费者总是从产品保障机制的信号中判断产品的可靠性水平,这对新产品销售有一定的借鉴意义。