Joint Optimization Of T Factory’s Three-dimensional Loading Problem And Vehicle Routing Problem

In recent years,the country has attached increasingly importance to the logistics industry.In this situation,the logistics industry of our country has developed rapidly.Nevertheless,logistics costs in our country have not yet been reduced to an ideal level.The requirement for reducing logistics costs is still urgent.The distribution link is one of the core links in logistics activities,thus reducing distribution costs is of great significance.In the distribution process,cargo distribution,cargo loading,and vehicle routing are three key components.If these three links can be optimized,large logistics costs can be saved and logistics operation efficiency can be greatly improved.Each of these three links corresponds to an NP-HARD problem.They are Splitting Delivery Routing,3D Bin Packing,and Vehicle Routing Problem.Many scholars have studied the problems in these three links.However,due to the high complexity of each problem and the difficulty of solving,most of the research is to optimize each link separately.But in fact,the logistics operation should never allow the three links to be divided into separate parts.Otherwise,it will make the company’s logistics inefficient and cause lots of waste of resources.For example,the management of T foundry is extensive.It still adopts a primitive approach.This is to say,when loading goods,its warehouse staff manually carry the goods.What’s more,they never calculate how to assign the goods to each vehicle and make placement plan in advance.Besides,when transporting the goods,it is completely separated from the loading link.It is only decided by the drivers of ZJ company,a three-party logistics company.The judgment of routing plan is often subjective and arbitrary.The management is so terrible that causes great waste of transportation resources and serious inefficiency in distribution.Under this circumstance,this thesis takes T foundry’s one-time outbound shipment order data as the research object.First,the management viewpoint of 3L-SDVRP-f is adopted,which means that splitting only occurs when the cargo can not be loaded by a vehicle.And the loading algorithm uses FFD algorithm.Then the problem is converted to the joint optimization of Three-dimensional loading and Capacited Vehicle Routing Problem,which is referred to as 3L-CVRP problem.Then a corresponding model for this problem is proposed.The model has two objectives,one is to minimize the vehicles’ total travelling distance,the other is to maximize the packing rate,including volume utilization rate and load-bearing utilization rate.And the model needs to be subject to two kinds of constraints,vehicle path constraints and three-dimensional packing constraints,each of which includes multiple constraints.Then the thesis designs suitable IGA-VNS algorithm and packing algorithm to solve the problem.The solution results show that,for the converted 3L-CVRP problem,through using the above-mentioned algorithm designed in this thesis,the driving distance of vehicles in T foundry can be reduced by 25.69%～58.88%,the volume utilization rate of packing can be increased by 14.83%～39.55%,and the load-bearing utilization rate can be increased by 8.29%～22.11%.Therefore,the research in this thesis has certain practical application significance.Additionally,the method of systematically optimizing the different businesses in distribution link in this thesis also has certain enlightenment significance for the management of enterprise business.