Lot-sizing Optimal Design For Hybrid Manufacturing-remanufacturing System Under Uncertain Environment

Industrialization has created tremendous material wealth and increased people's living standard,while it also brings out serious resource shortage and environmental problems.Sustainable development,as a new concept of development,has become common choice of mankind.Remanufacturing aims at lower consumption,lower emission and higher benefits.It is an industrial process in which worn-out products are restored to like-new condition.Differing from traditional manufacturing system,due to the diversity in returns' quality,number and remanufacturing cost,there are multiple uncertainties existing in remanufacturing system.This brings great challenges for the design and operation of such systems.Lot-sizing is one important part of the remanufacturing system and has the ability to improve the system performance.The influence of returns'quality in hybrid manufacturing-remanufacturing system(hereafter referred to as hybrid remanufacturing system)which including both manufacturing and remanufacturing system is focused in this thesis.The major work of this thesis is as follows:(1)Study on the profit of hybrid remanufacturing system.With the aim of maximizing total profit of the system,a simulation model of the system process is established for performance calculation,in which the quality uncertainty of returns is considered.The results demonstrate that considering the recovery rate and recycling quality grading,remanufacturing production planning can be more reasonable and maximize the profit of the system.(2)Study on the system lot-sizing optimization.The disassably and remanufacturing cost model is constructed by considering the quality condition of returns.Considering the cost parameters and customers'demands,the comprehensive profit model is constructed by using the two stage profit function.Research shows that the returns quality has important effects on the system lot-sizing and profit.The returns' quality is one of the most important factor of remanufacturing decisions.(3)Study on multi-objective lot-sizing allocation problem for hybrid remanufacturing system basing on TS-NSGA II.Selecting maximizing meeting customers' demand and minimizing total system cost as the objectives,multi-objective lot-sizing allocation problem model is established on the basis of Pareto concept.Considering the quality uncertainty,the operations research method is adopted to calculate system performance indicators of the system.A hybrid algorithm which called TS-NSGA ? is used to determine the lot size of hybrid system.This algorithm combines non-dominated sorting in genetic algorithm ? with tabu seach.The performance of the hybrid algorithm and the power of the hybridization are investigated for lot-sizing allocation problem.Promising results demonstrate the efficacy of the proposed hybrid approach in hybrid remanufacturing system.This thesis has investigated the lot-sizing problem with quality based on the hybrid manufacturing-remanufacturing system.Analytic method and dynamic evolutionary algorithm are used to study the lot-sizing problem which can guide the design and management of remanufacturing system and improves system capacity.