Juan J. Alba

A Comparison of the Performance of Two Advanced Restraint Systems in Frontal Impacts

Objective: The goal of the study is to compare the kinematics and dynamics of the THOR dummy in a frontal impact under the action of 2 state-of-the-art restraint systems. Methods: Ten frontal sled tests were performed with THOR at 2 different impact speeds (35 and 9 km/h). Two advanced restraint systems were used: a pretensioned force-limiting belt (PT+FL) and a pretensioned belt incorporating an inflatable portion (PT+BB). Dummy measurements included upper and lower neck reactions, multipoint thoracic deflection, and rib deformation. Data were acquired at 10,000 Hz. Three-dimensional motion of relevant dummy landmarks was tracked at 1,000 Hz. Results are reported in a local coordinate system moving with the test buck. Results: Average forward displacement of the head was greater when the PT+FL belt was used (35 km/h: 376.3 ± 16.1 mm [PT+BB] vs. 393.6 ± 26.1 mm [PT+FL]; 9 km/h: 82.1 ± 26.0 mm [PT+BB] vs. 98.8 ± 0.2 mm [PT+FL]). The forward displacement of T1 was greater for the PT+FL belt at 35 km/h but smaller at 9 km/h. The forward motion of the pelvis was greater when the PT+BB was used, exhibiting a difference of 82 mm in the 9 km/h tests and 95.5 mm in the 35 km/h test. At 35 km/h, upper shoulder belt forces were similar (PT+FL: 4,756.8 ± 116.6 N; PT+BB: 4,957.7 ± 116.4 N). At 9 km/h, the PT+BB belt force was significantly greater than the PT+FL one. Lower neck flexion moments were higher for the PT+BB at 35 km/h but lower at 9 km/h (PT+FL: 34.2 ± 3.5 Nm; PT+BB: 26.8 ± 2.1 Nm). Maximum chest deflection occurred at the chest upper left region for both belts and regardless of the speed. Conclusion: The comparison of the performance of different restraints requires assessing occupant kinematics and dynamics from a global point of view. Even if the force acting on the chest is similar, kinematics can be substantially different. The 2 advanced belts compared here showed that while the PT+BB significantly reduced peak and resultant chest deflection, the resulting kinematics indicated an increased forward motion of the pelvis and a reduced rotation of the occupants torso. Further research is needed to understand how these effects can influence the protection of real occupants in more realistic vehicle environments.

Optibody Project: Optimizing Vehicle Structures for Electric Light Trucks and Vans

The OPTIBODY project is focused on developing new modular structure architectures for electric light trucks and vans (ELTVs) which will improve the passive safety of the vehicle to help reduce the number of fatalities and severe injuries. The new concept will develop a structure composed of a chassis, a cabin that includes improved levels of comfort, protection and ergonomics of the user, a number of add-ons that provide protection in case of impact or rollover and also covering the topic of crash compatibility, including a good amount of the interaction with vulnerable road users. To achieve the objectives, an initial analysis of the ELTVs that are found on today’s markets is being made. Selected markets include Europe, U.S.A., Japan and Australia Together with an in-depth review on accidentology of these vehicles and a state-of-the-art research, a basis of requirements will be established. This is the starting point of the project, from which the first results have delimited the study to only L7e category vehicles (light urban delivery vehicles). These requirements will include legal aspects to be covered in the terms of passive safety, homologation, reparability and the integration of structural add-ons for added safety. Special attention is paid also to energy storage solutions, frontal and lateral compatibility, new design guidelines adequate to feasible solutions and new materials and processes. All the work is focused on improving all aspects considering the incoming electric vehicle technologies, which can be adequately applied in a very near future. All the work done will be exemplified at the end of the project by the demonstration of the designed add-ons and systems with a pilot demonstrator vehicle. This vehicle will show the developed chassis and cabin concept, complemented by different add-ons that could be utilized throughout different markets. Complimentary, the entire process is to be documented and a specialized publication with the best practices will be made available to the interested public, especially designers and vehicle manufacturers. With this attempt, the OPTIBODY project will provide new and improved safety systems for a segment of vehicles which do not take into account the same requirements as “regular” N1 category vehicles and which have shown to have a large percentage of fatalities on the road, including pedestrian incidents. This study has been limited to a selected type and category of vehicle, the L7e category (in Europe). The characteristics of these vehicles make them quite unique, since their low weight and low power make them apt only for urban driving and are widely used by goods delivery companies, urban services, etc. the requirements for their homologation are lower in terms of structure and safety, including pedestrian protection, hence the objective of this project to improve protection for occupants and vulnerable users. High accident rates with fatalities and severe injuries have been found for these vehicles. The OPTIBODY project is a pioneer enterprise in terms of improving safety in selected vehicle categories which have been traditionally less developed than regular cars or heavy goods vehicles. This approach will lead to an improvement in safety for all road users while interacting with these urban vehicles, which have less strict requirements than the rest. It is important to adequately design a chassis and body for the new upcoming electric technologies which now pose different risks in various aspects, such as energy storage, dynamics and accident behaviour. In general, the approach taken during this project will generate new and innovative ideas on the way that vehicles are designed and built with the use of electrical energy for their power. The risks of electrical mobility are being tackled as we speak, and the technological solutions that will be developed will improve the safety on our roads.