thesis_access.pdf (744.68 kB)
Download file

Imperfect Repair Strategies for Two-Dimensional Warranty

Download (744.68 kB)
posted on 15.11.2021, 06:08 by Varnosafaderani, Sima Rouhollahi

When a repairable product under warranty fails, the manufacturer (warrantor) has the choice to either repair or replace the failed product. When repairing a failed product, the degree of repair which affects the working condition of the product can vary, and this is assumed to have an impact on the cost of the repair. The main motivation of this study is to develop a warranty repair strategy that minimizes the costs associated with servicing the warranty. In this research, the product coverage is represented by a two-dimensional rectangular region with a free-replacement warranty. We propose an imperfect repair strategy that suggests employing imperfect repairs of a predefined degree, in prespecified subregions of the warranty region. The aim is to then minimize the expected warranty servicing cost to the manufacturer by determining the optimal partitioning of the warranty region for the chosen degrees of repair. Two imperfect repair models are considered, and for both, the expressions for the distribution of the times to imperfect repair and the expected warranty servicing cost per product sold are derived. We numerically illustrate our findings and compare the expected costs of the proposed imperfect repair strategy with those of previously developed repair-replacement warranty strategies.


Copyright Date


Date of Award



Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Statistics and Operations Research

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level


Degree Name

Master of Science

Victoria University of Wellington Item Type

Awarded Research Masters Thesis



Victoria University of Wellington School

School of Mathematics, Statistics and Operations Research


Chukova, Stefanka