Bertram Christian Geigl

Reconstruction of occupant kinematics and kinetics for real world accidents

A detailed study of vehicle and occupant movement during an accident is often of great interest. When reconstructing car accidents, quiet often questions arise regarding occupant movement and loading. This paper discusses the numerical results compared to experimental test results. For two selected full scale car to car collisions (frontal and side impact) three dimensional vehicle movement as well as dummy accelerations were compared. Additional emphasis were set on the influence of the crash pulse on the occupant behaviour. For the approach used a constant acceleration during the crash phase was assumed for the occupant simulation, which was performed by coupling the three dimensional car behaviour from PC Crash with a simplified MADYMO model of car interior, restraint system and 50% tile Hybrid III dummy model.

A NEW APPROACH TO OCCUPANT SIMULATION THROUGH THE COUPLING OF PC-CRASH AND MADYMO

A new interface has been developed between MADYMO and PC-Crash so that, after the reconstruction of an accident, only a few additional parameters regarding restraint system, seat and occupant must be defined. PC-Crash then creates all necessary input files for MADYMO and starts the occupant simulation. The results are then re-imported into PC-Crash for visualization and further analysis. This paper discusses the physical background of the model, its capabilities, and its limitations. One major point is the definition of the vehicle movement, which is an important input parameter for MADYMO. The model is validated in the paper through the reconstruction of crash tests. For the covering abstract of the conference see IRRD E201455.

Evaluation of the effectiveness of a bus and coach seat during rear end impact by means of sled tests

Based on data from statistical accident analysis, buses and coaches are still one of the safest means of transportation. Nevertheless numerous occupants get injured or suffer fatal injuries due to accidents. Although a high proportion of seriously injured casualties happen in accidents where the bus overturns or leaves the road, a large number of injuries are caused due to a normal collision, like a head-on or rear end impact. ECE regulation 80, referring to the strength of seats and their anchorages, was the initial starting point for this investigation. This regulation is limited to seat testing for frontal collisions, while this study deals with the results of testing in the opposite direction. Numerous coaches, especially double decker coaches, also have rearward facing seats and have consequently a different kind of loading to the seat structure. Summarizing, the results of the sled tests show a potential for further improvements in the energy absorption and design of the coach seat structure, to minimise the injury risk in such an accident configuration.