Rollover Analysis of Bus Using Body Section Method as per AIS-031 Standard 2013-26-0038

Automotive Industry Standard (AIS)-031 specifies the requirement of strength of large passenger vehicles in case of rollover. In India the certificate is granted after the successful completion of rollover test of the vehicle as per AIS-031. Complete vehicle is used for rollover test in which the vehicle is tilted laterally in the ditch of 800 mm. Such tests with complete vehicle are costly and unaffordable to small bus body builders. So according to Annex 2 of AIS-031, manufacture can carryout rollover on body sections of the vehicle. This is an equivalent approval method which is less costly compared to rollover test on complete vehicle. It requires detailed study of superstructure and selection of weakest body sections from the given superstructure of bus, which in turn requires mass and energy calculation of body section.

For doing rollover analysis using body section, bus is selected which has already passed a full-rollover test. Body section is a structural unit, which represents one part of the superstructure for the purpose of an approval test. A body section contains at least two bays (ring like structure of vertical pillars, roof stick and floor members) connected by representative structural members. Weakest body section was identified from superstructure using Computer Aided Engineering (CAE) tools. Results obtained from body section rollover were compared with full vehicle rollover simulation and physical test of full bus. Body section successfully passed the rollover simulation and found conservative compared to full bus rollover. This methodology will be useful in future to setup body section rollover test procedures for certification.