| With the developments of the social economic, the rhythm of people's work is hastened,people's demands for fresh frozen foods growing. To improve their marketing skills, Retailers increase higher demand on cold-chain logistics distribution business, usually restrictive requirements on the delivery time and quality of the delivery. For distribution companies, in considering the time window constraints, they must also take into account the stochastic characteristics that may effects the distribution such as potential congestion in urban road transport, and the perishable of the commodities for the purposes of achieving the minimum cost. Considering the time window constraints and stochastic characteristics, the writer constructs mathematical model to solve the problems of vehicle distribution in cold chain logistics which has important theoretical and practical significance.The writer base on traditional Vehicle Routing Problem with Time Windows, by considering randomness in refrigerated food distributing process, construct a mathematical model to solve the optimal shipping route, vehicle load, fleet and departure time. The objective function of the model aims at minimizing the sum of transportation cost, inventory cost, energy cost and penalty cost as related to violating time windows. Then the writer studies on the time-dependent truck running time in urban areas and time-varying temperature in a day, modifies the objective function as well as constraints in the above mathematical programming problem. Finally a case study was provided to demonstrate the feasibility and the results of applying the proposed models. Furthermore, the writer has done a sensitivity analysis and the analysis of the main parameters for the certification of this model. Results of this research provides guidance to the distributor such as the required fleet, vehicle departure time, load and distribution routes for carriers on making the optimal shipping decisions. This thesis has a good application value.
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