Finite Element Simulation Analysis On Integral Body Bus Rollover Test

With the rapid development of passenger transport industry, the bus fleet increases year by year. Events of many passengers deaths have occurred because of bus rollover accidents, which have caused the government and enterprises’ attention. Passenger passive safety and safety body structure have become research priority and focus about modern bus technology. The new rollover test standard GB 17578-2013 "Requirements and test methods of strength for the superstructure of bus" has been enforced, which encourages enterprises to further focus on bus rollover safety. In this context, this paper carried out certain 6120 bus to do bus body frame static strength analysis and simulation about vehicle rollover feature.In this paper CATIA 3D skeleton model is established according to CAD drawings, and in HyperMesh and LsDyna the body frame finite element model and vehicle rollover simulation finite element models are established. Analysis on static strength of bus body frame by OptiStruct in bending and torsion conditions are done and the maximum stress components are got. Results show that the strength meets the requirements; after the modal analysis, the first 10 modal frequency and vibration mode of body skeleton is got. The frequency are from 8.52 Hz to 21.41 Hz, meet the design requirements of 5Hz to 33 Hz.Using LS-DYNA to do the vehicle rollover test calculation, the results are processed by HyperView and HyperGraph. The upper structure energy absorption, vehicle energy absorption, the occupant survival space invasion possibility, the centroid velocity and acceleration are analyzed, the upper structure energy absorption reached 92.1% which meets regulatory requirements. Occupant safety margin has small living space, with the minimum distance 1.841 mm.Because of the large deformation of side panels, bus design principles of anti-rollover deformation are discussed and simulation verification about the principles are done.Structural improvements are done according to the principles, and the simulation results show that the improved method is practical. The living space margin increases by 10.48 mm with the total mass of basic unchanged. In this paper, a PH reference method, evaluates quantified grade on the superstructure strength of the bus, and the calculation shows the bus appraisal parameter DI? is originally 0.428, star rating result is 4 stars; after structural improvements parameter becomes 0.397, the result is just reached star rating 5 stars, this evaluation method is feasible and effective.