Research On The Structure Of Large Integral Coach With Safety Partition

With the today's rapid economic divestment,people pay more attention on the environmental protect and the transit trip.Public transport ranks high in people's daily going.In our country,coach takes as the important part of the public transport.The holding of coaches and the number of passengers are rising these years.Nowadays,with the booming of the passenger transport,people focus more on the safety of the coach.By now,government has published safety laws and regulations to ensure the coaches' safety,such as ‘Provisions of strength for the superstructure of bus,‘the safety structure provisions of the bus',‘vehicle safety regulations'.The regulation has specified the size and the safety of the bus,and also stipulated that all the bus body which longer than 11 m should use the integral frame body.And in 2012 government enforced all the bus companies to execute the safety laws and regulations.So many companies have to increase the members to satisfy the safety regulations.Aimed at the situation and market demands,based on the former research,we bring up the idea of safety partition and design the structure of large integral coach with safety partition.The new body structure wants to satisfy the rollover safety and strength,stiffness performance,also qualify the lightweight.The content of my thesis as follows;First,based on the analyze of the integral bus structure and performance,we accomplished the design of the structure of large integral coach with safety partition.First step analyze the bearing of the existed integral bus,understand the stress characteristic of the bus member.According to the loading performance,we try to design the new body structure.The design of new body structure is based on the safety partition idea.The whole structure takes the three parallel-grider body,and sets two bus doors,front and rear.And we set two safety partitions in the coach,one is behind the front car door,the other is before the rear door.The structure of the safety partition is an entire truss work.And the partitions are jointed with the closed-loops in the coach,partitions form two rigid walls encircle the passenger zone.Partitions can effectively decomposed the stress,and enhance the whole coach bearing capacity.Final,according to the government requirements,we designed the seats,steps,safety extra etc.In all make up the new body structure initially.Second,according to the new body structure we have already made,take the whole coach static performance analyze.First,set up the whole coach finite element model under the two-dimensional drawing.Because of the static analysis needs,we used the bar-shell mixture elements.The general of the whole body used the bar element,and the large-section and the main member used the shell element.Second the process the finite element model with free mode,strength and stiffness analyze.Through the performance results,we find high stress member under the strength condition.We improve the high-stress member through optimizing the structure and changing the section size.Final,the whole coach has good performance through the optimizing.Third,we analyze the new body rollover safety and improve the design.For all the coach needs to satisfy the government safety laws and regulations,we set up the whole car rollover stimulate model to improve the rollover safety performance.First,we approach the rollover safety evaluation criterion,and get know of the demand of the rollover test,living space size and the evaluate criterion.Second,we use whole-shell element to simulate the rollover condition.We define the testbed,living space,contact,control cards and others in the finite element model.Checking the upper structure change,living space invade,energy change in the results,optimize the high deforming member.After two-step optimize,the final model has been made.The final body structure of large integral coach with safety partition having good rollover safety performance and static performance,also realizing the lightweight design.