ACHIEVING LOW WEIGHT AND LOW COST BODY FOR A NEW COACH TYPE USING SIMULATION AND PREVIOUS LESSONS LEARNED

摘要

A rollover event is one of the most crucial hazards for the safety of passengers and crew riding in a coach. Although the percentage of rollover related accidents among all types of accidents is not the highest, it is by far in the rate of fatalities. Today the ECE-R66 regulation, which is the most important passive safety regulation in the coach industry, sets the minimum rollover strength requirements of a coach body. According to ECE-R66, the certification can be gained either by full-scale vehicle testing, or by calculation techniques based on advanced numerical methods (i.e. nonlinear explicit finite element analysis). The assessment of compliance to ECE-R66 is based on checking the possible intrusion of every pillar section with the survival space, set for the protection of passengers and dimensions defined in the regulation. Numerical simulation is clearly the most efficient way to assess the rollover strength of a new coach type, for which a physical prototype may not be available yet, such that in case of failure design measures can be taken early in the design process. At Temsa R & D and Technology, rollover simulation according to ECE-R66 regulation is an integral part of the coach body design process. Whether luxuary coach or midicoach, all Temsa vehicles are certified using simulation. The usual simulation process starts at the time where the coach body design is finished, all CAD data is released, components' mass and location are clearly defined, in-another-words the coach design is almost fixed. In case of failure of compliance to ECE-R66, improvement means are possible but limited. In this work, first simulation principles according to ECE-R66 will be explained. Then, how extensive usage of numerical simulation early in the design process, combined with previous experiences and lessons learned" in other vehicles, made achieving lower cost and lower weight coach body possible will be presented. The result of this work is 12% lighter body made with lower grade steel, compared to its predecessor.