The Optimization Research On The Distribution Route Of Urban Cold Chain Logistics

As one of most the important part of urban cold chain logistics system, cold-chain logistics distribution contribute to up to 52% of the total cost. However, cold-chain logistics is still in the early stage of development in China now. Low coverage, high cost and poor dispatching rationality problems have emerged in endlessly, "broken point" phenomenon causes food safety problems frequently. At the same time, the prevalence of the fresh food electronic commerce and cold-chain home delivery orders for cold-chain logistics brings out the "small batch, big scales, multi-temperature" characteristics, further increasing the city, the necessity of cold chain logistics distribution scheme optimization with difficulty. To solve this problems of cold-chain logistics distribution, this paper was conducted respectively from the single category cold-chain logistics distribution and multi-temperatures, by adjusting the cold-chain logistics distribution mode and optimizing the logistics scheduling process, to improve the efficiency of cold-chain logistics distribution and reduce the cost of cold-chain logistics. This paper may provide an effective optimization scheme for urban cold-chain logistics distribution.The main research content of this paper is as follows:(1)Through the analysis of the key elements in the cold chain logistics system, it illustrates the importance of urban cold-chain logistics distribution; And summarizes the existing urban problems of cold chain logistics distribution; At the same time, it analyzes the cost and builds a general model of urban cold-chain logistics distribution optimization basing on the key elements of the city of cold chain logistics.(2) In view of the single-temperature category urban cold-chain logistics distribution problems, it establishes an optimization model of urban cold-chain logistics distribution considering split delivery. This part considers the introduction the corruption rate of food and the influence of outside temperature change on the cold-chain logistics distribution cost comprehensively, which makes the research more practical reference significance. An improved simulation algorithm was designed to solve the model, which introduces "granular neighborhood" strategy to Plant Growth Simulation Algorithm (PGSA). The "granular neighborhood" strategy effectively improves the solution efficiency and speed of the algorithm. Numerical experiments verify that the split delivery cold-chain logistics distribution model can effectively realize the whole optimization of cold-chain logistics. To a certain extent, this part could give some advices to the development of urban cold-chain logistics distribution model.(3) Considering the characteristics of multi-temperature joint distribution, with flexible compartment sizes and split delivery among different temperature range, this paper establishes an optimization model of multi-temperature joint distribution. A variable neighborhood tabu search algorithm was designed to solve the model and to reduce the distribution cost. Numerical experiments indicate that different loading and distribution strategies could influence the distribution efficiency extremely. It demonstrates the effectiveness of the raised model and the VNTS algorithm.