Route Selection Of Containers Multimodal Transportation For Perishable Goods Based On Multi-objective Optimization

With the improvement of people’s living standards,the demands for perishable goods have grown dramatically.As an important method for transporting perishable goods,cold chain transportation has developed gradually in China.At present,multimodal transportation is an intensive and efficient new mode of transportation by adopting multiple vehicles for combined transportation.It reduces transportation costs,environmental pollution and now is favored by more and more businesses.Therefore,the circulation of goods between the production and marketing which takes multimodal transportation and refrigerated containers as transportation equipment,has become a vital channel for perishable goods transportation.Based on the analysis of factors influencing the multimodal transportation routes selection for perishable goods,this paper constructs a multi-objective route selection model that considers the quality loss rate,the total cost of transportation,and the total energy consumption of transportation,which reduces transportation costs while reducing quality loss and energy consumption and improves the overall level of multimodal transportation.The main research work of this paper includes the following aspects.(1)The relevant theories of perishable goods,multimodal transportation and cold chain transportation were sort out,and the applicability of refrigerated container in the field of perishable goods multimodal transportation was analyzed,combining the domestic and foreign development status of cold chain transportation and multimodal transportation.According to the time-dependent characteristics of the multimodal transport network,combined with the perishable goods transportation,the timedependent transportation network and process suitable for refrigerated container multimodal transportation were proposed.(2)The paper analyzed the relevant factors affecting multimodal transportation routes selection for perishable goods.The analysis focused on quality loss rate,total transportation cost,and total energy consumption of transportation.Considering the change law of perishable goods damage rate over time,and analyzing the factors such as departure time at the starting point and departure schedule of nodes,the quality damage rate of perishable goods during the whole transportation process was determined.The concept of time penalty cost was introduced,and transportation cost and replacement cost were integrated to construct the objective function of total transportation cost.The working principle of refrigerated container was analyzed and the impact of perishable goods breathing heat,ambient temperature and solar radiation intensity on energy consumption of refrigerated container were considered.Furthermore,combined the energy consumption of various transportation methods,a calculation method for the total energy consumption of transportation was proposed.(3)Comprehensively considering the three aspects of quality loss rate,transportation cost,and transportation energy consumption,the paper established a multi-objective optimization model.Then,the NSGA-Ⅱ algorithm suitable for the model was designed.Aiming at the shortcomings,traditional NSGA-Ⅱ algorithm was improved by changing crossover operator and mutation operator and test functions were introduced for comparative analysis.(4)Three commodity flows of perishable goods were selected and solved.The entropy-weight TOPSIS evaluation method was introduced to calculate the Pareto optimal solution set and the conclusion that the multimodal transportation mode was better than the single mode of transportation was draw under the condition of considering various factors.Finally,through sensitivity analysis of railway freight rates and delivery deadlines,the conclusions were draw that a proper reduction of railway freight rates can promote the ability of railway transportation to attract goods and reduce transportation energy consumption,and according to the needs of customers,reasonable transportation plans can ensure the completion of transportation tasks as required while taking into account factors such as benefits and the environment.