Research On Disassembly Sequence And Lot-sizing Disassembly Planning Problems For Wast Products

As the human history has entered the21st century, the world economy has been developed at a rapid pace in recent decades. With the creation of material prosperity, the amount of resources invested in production increases sharply, living environment is destructed, and environmental pollution is worsening. Environment, resources and energy have become global issues of common concern. In this thesis we take disassembly of used product as research background, study several optimization issues of disassembly sequence optimization and lot-sizing disassembly process. The research results and core content are mainly presented in the following five aspects:(1)The optimization problem of completely disassembly multi-objective disassembly sequence is studied. Aiming at solve disassembly sequence optimization problem, a multi-objective mathematical model is established with minimizing the disassembly time and maximizing the disassembly profit. The linear weighted method is used to transform the multi-objective model into single objective one. An improved scatter search algorithm is presented, which embodies PPX (preserving priority crossover) combination operator and local search operator. The effectiveness of proposed model and algorithm for multi-objective disassembly sequence optimization problems is proved by test result.(2)The optimization problem of selective disassembly multi-objective disassembly sequence is studied. According to the characteristics of selective disassembly, a mathematical model is established. Meanwhile, optimization objectives of minimum of the disassembly time and maximum disassembly profit are considered. And an improved multi-objective scatter search algorithm (MOSS) is proposed. In this thesis, according to the feartures of multi-objective problem to establish P set and the initial reference solution set. Precedence relations will be maintained during the cross (PPX) as a combination operator, Using a modified local search strategy to further improve the quality of the new solution, using external archive method storage Pareto solution set. A case study is used to illustrate the feasibility and effectiveness of the proposed method.(3)The optimization problem of selective disassembly sequence with multi-resource constraints is studied. Modeling of an AND/OR graph of product according to the features of disassembly is adopted. The connection relations and precedence relations among components of product are shown by the model. The mathematical model of the optimization problem of selective disassembly sequence is established according to the characteristics of selective disassembly problem. At single objective aspect, this work proposes a scatter search (SS) with the goal of maximum profit. At multi-objective aspect, this work establishes a mathematical model of the optimization problem with the goals of maximum profit and minimum disassembly time. Also a scatter search (SS) is proposed, which includes a crossover combination operator which keeps the precedence relations, and an improved local search strategy to improve the quality of new solutions. The study shows SS performs better in solving problems proposed in this thesis.(4)The optimization problem of sequence-dependent selective disassembly sequence with multi-resource constraints is studied. According to the characteristics of selective disassembly sequence optimization problems subject to multi-resource constraints and sequence-dependent process time, this thesis establishes a multi-objective mathematical model with the goal of maximum profit and minimum disassembly time. An improved multi-objective scatter search algorithm is presented, which embodies diversification generation method, crossover combination operator which keeps the precedence relations, reference set update method. The algorithm makes use of an improved local search strategy to enhance the quality of the new solution, and make use of external archive method to storage Pareto solution set. The effectiveness of the model and algorithm is tested in this thesis.(5)The lot sizing disassembly planning problem subject to multi-resource constrains is studied. The author establishes an optimization model for lot sizing problem of selective disassembly with multi-resource constrains. Using CPLEX software, the problems can be solved to optimality, satisfy external demand selective disassembly with multi-resource constrains. Via using some problem instances, computational experiment is made, and the results show that the model is correct and effective.In conclusion, mathematical models are established to solve disassembly problem of used product. According to the characteristics of mathematical models, this work designs different modern optimization algorithms to solve the problems and provides effective solutions. The validity of the effectiveness of models and algorithms is demonstrated by analyzing a large number of experiments, which provides important reference and guidance in solving this type of problem.