【作者】 姜勇；

【导师】 庄蔚敏；

【作者基本信息】 吉林大学 ， 机械工程， 2011， 硕士

【摘要】 本文基于实验室自主开发的脊柱式龙骨大客车车身结构,参考欧洲经济委员会针对客车侧翻碰撞上部结构强度制定的ECE R66标准建立了整车有限元模型并提取封闭环结构进行侧翻安全性结构改进与分析验证。通过对该客车车身结构进行初期侧翻碰撞仿真分析,结果表明侧翻碰撞完成后车身内部部分构件侵入乘员生存空间,其侧翻安全性不能达到标准要求。通过观察整车结构变形分布情况发现,在其侧围结构下腰梁接头处多个杆件交叉焊接是侧翻碰撞中的主要变形位置。本文针对下腰梁接头结构这一特点提出了一种新的下腰梁下沉结构,将侧围下腰梁下移远离地板横梁与侧围连接点。这种结构使得下腰梁以上的主要变形结构处侧围竖梁是贯通的,在一定程度上满足联通式刚性封闭环的要求。通过封闭环结构侧翻碰撞仿真试验发现,与之前相比改进后结构的碰撞冲击能量下降四分之一左右,车身结构变形明显减小。在下腰梁下沉结构基础上,为实现降低车身结构质量的目的,本文提出了多个结构优化方案,并验证其侧翻安全性。最后确定的综合改进方案,在保证具有与改进前相同侧翻安全性的基础上,有效的降低了车身结构质量。本文在下腰梁下沉结构侧翻封闭环的基础上,参考乘用车正面碰撞采用的吸能方式在其顶盖侧边梁与侧围上纵梁并焊区附近加装泡沫铝缓冲吸能结构改进其侧翻安全性。计算结果表明,由于下腰梁下沉后车身封闭环刚度已经很大,加装吸能结构后变形量的减小并不明显。但缓冲吸能结构在车身产生变形前吸收了较多撞击能量,阻止其向乘员舱内传播,有效的保证了大客车乘员的生命安全。本文最后采用脊柱式龙骨客车整体车身结构模型,通过引入下腰梁下沉结构与缓冲吸能结构改善其侧翻安全性。仿真分析结果表明改进后的整车车身结构在侧翻碰撞中变形减小,车身内部结构对乘客生存空间没有任何侵入,碰撞冲击能量下降,极大地提高了脊柱式龙骨客车侧翻安全性。更多还原

【Abstract】 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.更多还原