Improvement Research On Rollover Safety Structure Of A Full-load Bus Of Spinal-type

This paper is based on the body structure of spinal-type bus which is developed by laboratory to build finite element model of bus,Commission for Europe developed regulation No.66 to aim at the strength of the bus superstructure in rollover crash is for reference, and extract the closed ring structure to improve and analyse rollover safety structure.It's indicated that parts of the structure inside body irrupt the passengers space after rollover crash by the initial rollover crash simulation of the bus body, the rollover safety can not meet the regulation requirement. It's found that the cross-weld joints of bar within lower waist beam is the main deformed position in rollover crush by observing the distribution of vehicle deformation. This paper aims at the characteristics of joints of lower waist beam, proposes a new lower waist beam sinking structure to making the lower waist beam of side wall down to be away from the connection point of floor beams and side wall. This structure makes vertical beams of side wall are transfixion in major deformation above the lower waist beam, meeting the requirement of link-type rigid closed ring to some extent. It is found that to be compared with the previous, about a quarter of the collision impact energy decreases, body structure deformation reduces significantly through the rollover crash simulation. This paper presents a number of structural superior programs and verifies its rollover safety to achieve lightweight body structure based on the lower waist beam sinking structure. The finally comprehensive improvement program reduces the quality of body structure effectively and ensures it has the same rollover safety as before.In the case of lower waist beam sinking structure of rollover closed ring, the paper adopted the method of adding foamed-aluminium energy-absorbing structure at the round of tip side-girder and welded girder in the side wall to improve rollover safety referencing frontal crash energy-absorbing method of car. The conclusion was demonstrated that deformation does not significantly decrease after the installation of energy-absorbing structure, because the stiffness of closed ring of body is already large. But the buffer absorbing structure absorbed more crash energy before the deformation of body, which can prevent its spread to the passenger cabin, which guarantees the safety of passengers effectively.Finally, this paper uses body structure model of spinal-type bus to improve its rollover safety by introducing lower waist beam sinking structure and buffer absorbing structure. The simulation result shows that the deformation of body decreases in rollover crash after being improved, the internal structure of the body doesn't penetrate the passenger safe space, the impact energy decreases, improves the rollover safety of spinal-type bus greatly.