The Study Of Two-Dimensional Warranty Claims Forecasting And Maintenance Strategy Design

With the fierce competition in the market and consumer awareness of selfprotection need awakening,the competitive emphases of modern manufacturing enterprises have changed from product quality,price to cost,reliability and warranty service.This dissertation focuses on products sold with a two-dimension warranty,taking excavator for an example.From the perspective of the manufacturer,in view of problems in warranty management and the current state of warranty research,this study presents warranty claims prediction models and methods for optimal warranty policy making.In the first part,this study conducts warranty claims forecasting models based on perfect maintenance and minimal maintenance,respectively,for products sold with a two-dimensional warranty.Because manufacturers of products sold with any type of warranty incur additional costs from servicing customer warranty claims,accurately forecasting the number of warranty claims has become increasingly important to manufacturers.This study proposes two models considering usage rate to forecast the number of failures of products sold with a two-dimensional warranty policy based on perfect maintenance and minimal maintenance,respectively.Then this study uses simulation to test the performance of the proposed models.The results indicate that the proposed models have good precision of prediction.In the second part,two models based on a generalized renewal process considering usage rate to predict claims of products sold with a two-dimensional warranty policy are developed.Both simulation and real data collected from an excavator manufacturer in China were conducted to validate the presented models.In order to explore the impacts of the usage rate in the process of predicting claims,the usage rate are divided into three groups in the experiment: low,medium and high.The results of this study show that the predictions obtained from these proposed models fit well to actual data.In the third part,this study proposes a warranty claims forecasting model for recently launched product sold with a two-dimensional warranty.Since the amount of the historical claim data for such products is not large enough,it is difficult to develop predicting models with good performance.Records of warranty claims data of similar products could be used to forecast the number of warranty claims of recently launched products.A two-phase forecasting algorithm is proposed.Based on this algorithm,this study proposes a warranty claims forecasting model considering usage rate for recently launched products.The results derived from simulation study show that the proposed algorithm outperforms commonly used model without considering usage rate.In the fourth part,this study conducts a design and optimization research on twodimensional warranty maintenance strategy based on the actual problems.This study proposes a mathematical optimization model to optimal number and degrees of preventive repair to minimize the manufacturer's servicing cost.A numerical example is given to validate the presented model and sensitivity analysis is conducted.The results indicate that the presented model may effectively reduce servicing cost during the warranty region.The research is helpful for manufacturers to make decision on warranty policy design.