Research On Customized Two-Dimensional Flexible Warranty Policies

In recent decades,the trend of economic globalization has become more and more significant.Meanwhile,with the rapid development of science and technology,manufacturing technology and productivity have been improved substantially.The overcapacity in electromechanical industry has led to increasingly fierce competition globally.Customers' demand for products and service tend to be differentiated,diversified and personalized.The original standardized products and service cannot meet the customers' requirement anymore.Thus,the customized production and service mode has emerged.By providing customers with differentiated products and service,it can help the manufacturers to win customers and establish competitive advantage.Warranty service is an imperative means of promoting products and improving customer satisfaction.The existing warranty research mainly focuses on standardized warranty service strategy,which is difficult to meet diversified market needs.In recent years,research on customized two-dimensional flexible warranty has attracted attention.This thesis takes automobiles and other products as the research object.Customers are divided into different groups according to their usage rate.Aiming at profit maximization and warranty cost minimization,the flexible basic and extended warranty strategy are designed and optimized respectively based on the two-dimensional warranty theory.The main research contents are as follows:(1)Considering the impact of the correlation between product usage time and usage on failure rate,a two-dimensional warranty failure model is established by using Copula function.Minimal maintenance and non-equal strength periodic preventive maintenance are combined,sales and profit model are established to optimize the basic warranty period,warranty cost,and product price by the manufacturers.Based on customer usage,manufacturers design two basic warranty strategies: standardization and flexibility.The case study proves that minimizing the warranty cost cannot guarantee maximum profit of manufacturers.With the improvement of the warranty strategy's flexibility,manufacturers can obtain higher profits and customer satisfaction.(2)Considering the difference between product usage rate and extended warranty's purchase time,the customized extended warranty service model is studied.The edge method is adopted to establish a two-dimensional failure model,and the difference of product's failure probability due to different usage and usage time is defined.Minimal maintenance is adopted to eliminate sudden failures of products,and virtual age method is adopted to describe preventive maintenance effect.Considering factors such as the start time of preventive maintenance,maintenance period,maintenance intensity and extended warranty interval,the optimization model of maintenance strategy and warranty cost are established.The case study shows that the improved preventive maintenance strategy can reduce maintenance cost effectively,and customized maintenance and warranty strategy can help reduce the number of product failures and warranty cost,improve customer satisfaction and product competitiveness.(3)In the existing flexible warranty strategy based on product usage rate,the customer groups division method is simple,and the product reliability index cannot be considered.In view of the above shortcomings,this thesis ensures that the product reliability is higher than the threshold of preventive maintenance by setting the reliability threshold of preventive maintenance.Warranty cost model is established to optimize the period and strength of preventive maintenance.Indirect grouping strategy is adopted to group customers with different usage rate and optimize overall maintenance tasks.The case study shows that it is difficult to minimize warranty cost by simply categorizing customers.The group maintenance strategy helps manufacturers make full use of maintenance resources and decrease the warranty cost.The contributions of this thesis lie in the systematically optimize flexible warranty and maintenance strategy,and also in the innovation of two-dimensional fault modeling,preventive maintenance method,customer grouping maintenance and flexible warranty design.The relevant research content provides a theoretical basis for the design of customized flexible warranty strategy,which is a further development of the two-dimensional flexible warranty theory.