The Study Of Vehicle Route Replanning For Cold Chain Logistics Under Emergencies

With the increasing demand of frozen and refrigerated food, high-cost and low-profit cold chain logistics faces enormous challenge. In the cold chain logistics, distribution cost accounts for a higher ratio and whether vehicle route planning is reasonable has an effect on distribution costs. In the distribution process, emergencies such as traffic congestion, road reconstruction maintenance or traffic accidents are unforeseen and can’t be avoided. Once these events happen, not only distribution costs will increase, customer satisfaction will be affected, so vehicle rout replanning is particularly important.This paper analyses the characteristics about cold chain logistics distribution and defines the emergencies which this paper studies firstly. After taking five kinds of costs into account, which include the cost of the assigned, transportation costs, the damage cost of goods, the cost of energy consumption and the punishment costs for over time window, this paper establishes a model of cold chain logistics vehicle rout replanning whose objective is to minimize the distribution cost. Secondly, this paper designs suitable transition rule and pheromone updating rules about the ant colony algorithm which combines with the problem and the model the paper studies. Finally, this paper solves and analyses an instance by two stages including before and after emergency, and studies the information inspire factor, expectation heuristic factor and pheromone evaporation coefficient which proves the model, algorithm and parameter values in this paper is reasonable and applicable.This work not only provides the theory for enterprises which focus on cold logistics when they replan vehicle route under emergencies, but also brings the reference when they design the number of vehicle and the departure time, check arrival time, adjust appointment service time, forecast the quantity about the damaged goods and various cost and so on.