During the frontal pendulum impact on commercial vehicles as per AIS029, flat front end vehicles usually show severe cabin deformations. In most of these cases the impact load directly acts on the cabin structure resulting in severe loading of front part of the cabin. This is likely to result in failure of cab mounts causing cabin separation, undesirable cab movement and high intrusion inside the cabin structure. This unpredictable cabin behavior exposes cabin occupants to high risk of injuries.
The possible way of reducing occupant injuries in pendulum impact test is to limit the undesirable displacement of the cabin structure during the test and maintain its structural integrity. This can be achieved by having multiple load paths to transfer loads from firewall structure to cabin underbody structure, chassis frame structure and controlling cabin displacement in case of cab mount failure preventing excessive rotation of cabin structure.
In this paper various concepts are discussed to maintain structural integrity of cabin during pendulum impact test. Also discussed different types of protection devices that acts as a stopper to limit undesirable displacement of cab structure during the test as discussed above. These concepts were developed based on CAE simulations and feasibility studies were done so that these concepts can be implemented on existing commercial vehicles as add on components.