Search Results

Public transport is being promoted by many governments in order to reduce road congestion and emissions. When a bus accident occurs it often becomes the focus of media and public attention, especially because the people involved had confidence in the transport and sometimes it is the only means of transport available to them In Europe, in 1987, with the aim of reducing the number of fatal casualties in rollover accidents, the UNECE Regulation 66 “UNIFORM TECHNICAL PRESCRIPTIONS CONCERNING THE APPROVAL OF LARGE PASSENGER VEHICLES WITH REGARD TO THE STRENGTH OF THEIR SUPERSTRUCTURE” [1] was published and in 2000 the UNECE Regulation 16 “Uniform provisions concerning the approval of safety belts, restraint systems, child restraint systems and ISOFIX child restraint systems for occupants of power-driven vehicles” included specific requirements for coaches. From this stage, the countries where passive safety regulation is a concern have adopted various strategies.

Durability is one of the most important goals in the current state-of the-art design of new vehicles. Usually the durability performance is validated by the vehicle manufacturers driving directly the prototypes in field or through endurance schedules on proving ground fatigue surfaces. The validation procedure driving directly in field is very expensive and time-consuming. The reliability and accuracy of validations in proving ground surfaces are many times unknown, mainly because such endurance schedules are not fitted to the market (driving conditions and type of roads) and historically are based on empirical procedures. This paper discusses how IDIADA has developed a methodology to design accelerated durability schedules which obtain less expensive and fast durability validation procedures, as well as being reliable and fitted to the market and durability targets.

Rollover resistant structures for coaches have been developed in the nineties, but recently, as the price of the steel has almost doubled only in the last year, the use of new materials for these superstructures has become more cost efficient. The price gap between high strength steel price and mild steel has been reduced and the use of this material is emerging into commercial vehicle industry. High strength steel may lead to weight and cost reduction but a new energy absorbing mechanism has been identified with the use of structural foam. On this study a solution using high strength steels and structural foam has been designed to improve the energy absorption and reduce the final weight of a current rollover resistant bus structure. Several parts of the bus structure have been manufactured with the final selection of structural foam and high strength steel. The prototype parts have been used for test and manufacturability.

A rollover accident of a bus or a coach is particularly dangerous. Many different aspects must be taken into account in order to reduce occupant injury. The most important criteria are structural resistance, occupant restraint systems and seat anchorages. Spain has complied with ECE R-66 since 1992. For this reason, bus and coach manufacturers have had to improve the structural resistance. IDIADA has developed a simulation procedure using finite element analysis for studying the structural resistance during a rollover. Experimental tests of a representative section of the structure and bending tests of the different beams are conducted in order to evaluate the analysis simulation. Due to the close correlation between the simulation and the real test, IDIADA is currently capable of fully developing structures which comply with ECE R-66 without actually performing a rollover test.