Ageing Effect on Crashworthiness of Bus Rollover

International standards related to protection of occupants in rollover accidents are generally applied on new vehicles and regulated for design approval. However, there is no standard regulation governing rollover crash performance of aged vehicles and no proper systematic test to monitor it. It is known that vehicle structural integrity deteriorates after years of operation undergoing various service environments and conditions. The scenario is worsen if the vehicle is poorly maintained and still in operation beyond its lifespan. These factors directly influence the vehicle crashworthiness level and affects its safety. The present paper attempts to show how ageing factors like corrosion and deterioration of mechanical properties may change the overall vehicle structural strength and hence its crashworthiness performance. As a case study, rollover analysis according to European standards (UNECE R66) was set up on a finite element bus model using LS-Prepost and simulation was performed using LS-DYNA . Different levels of condition due to ageing effect were included in the model to examine the changes of rollover performance of the bus. Aged bus rollover studies from real world crashworthiness investigation in Malaysia were referred for comparison to support the argument. Result shows that ageing factors directly influence the performance of vehicle crashworthiness.