A Methodology to Evaluate the Design of Road Restraint Systems under Motorcyclists' Collisions, using Computer Simulations 2011-36-0037

A recent Spanish survey reveals that opposite to vehicle and pedestrian accidents, motorcycle fatalities have increased in the last 7 years. One third of these correspond to collisions of motorcyclists against roadside guardrails. In response to this serious safety demand, manufacturers and governments in Spain and France have started their own initiatives in both, launching smart road restraint systems safer for vulnerable users, and developing new protocols and regulations to evaluate the behavior of these systems against motorcyclist collisions.

In order to provide support to roadside guardrails manufacturers to fulfill these regulations and develop friendly systems for motorcyclist, Applus IDIADA is carrying out a project to develop a robust methodology to create CAE simulation models that represent these impacts. This paper resumes the work done during the first phase of this project, which consisted on correlate two impact tests performed at IDIADA testing facilities following Spanish regulation UNE 135900: "Post Centered Impact" and "Mid Span Centered Impact," both at 60 kph and following an impact trajectory of 30° respect to the barrier. The barrier tested and simulated had a deformable continuous system, to absorb impact energy and redirect the rider on the road. A detailed model of the barrier was developed using a commercial explicit CAE code, including fixings and correlated material properties. A Hybrid III dummy model was employed positioned leaning on its back, orientated 30° respect to the barrier, and wearing a motorcycling helmet.

Signals measured on the neck of the virtual dummy were compared to those measured on real tests, and in most cases clearly represented the same kinematics and dynamics of real dummy, during the first 30 ms of the impact, when the highest values were reached. Once a feasible virtual model of the test was defined, simulation allows modifying parameters that constitute the test like dummy's speed, impact trajectory, or building characteristics of the barrier design, in order to evaluate the barrier behavior under different impact conditions.

As a conclusion, computer simulation has demonstrated to be a powerful tool that firstly represents with an acceptable rate of accuracy Spanish regulation UNE 135900 for motorcyclist impact tests. Secondly, it can be used to optimize the design of roadside barriers improving its building parameters, to reduce riders injuries on the head, neck and vertebrae, and with a considerable investment saving.