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Restraints systems (airbags and seat belts) have been proven to be very effective in occupant protection in crashes. Timely deployment of these devices is very essential for meeting performance requirements. Precision and reliability in restraints deployments demand selection of a robust sensing configuration that caters to the wide variations of real world. This paper highlights complexities involved in engineering of restraints sensing configurations through different case studies on vehicle programs. The paper explains the need for restraints sensing configuration optimization and well defined sensing strategies for a robust solution in real world. A methodology is discussed to achieve good discrimination between crashes of different types and severities. Virtual and physical test data collected at different stages of vehicle development is used. It is found that criteria for threshold levels in restraints sensing requires efforts to identify real world usage variations.

Integrating safety features may lead to changes in vehicle interior component designs. Considering this complexity, design guidelines have to take care of aspects which may help in package feasibility studies that consider systems performance requirements. Occupant restraints systems for protection in side crashes generally comprise of Side Airbag (SAB) and Curtain Airbag (IC). These components have to be integrated considering design and styling aspects of interior trims, seat contours and body structure for performance efficient package definition. In side crashes, occupant injury risk increases due to hard contact with intruding structure. This risk could be minimized by cushioning the occupant contact through provision of SAB and Inflatable IC. This paper explains the methodology for deciding the package definitions using Knowlwdge Based Engineering (KBE) tools.

The vehicle crash signature (here on referred as crash pulse) significantly affects occupant restraints system performance in frontal crash events. Restraints system optimization is usually undertaken in later phase of product development. This leads to sub-optimal configurations and performance, as no opportunity exists to tune vehicle structure and occupant package layouts. In concept phase of development, crash pulse characterization helps to map occupant package environment with available structure crush space and stiffness. The crash pulse slope, peaks, average values at discrete time intervals, can be tuned considering library of restraints parameters. This would help to derive an optimal occupant kinematics and occupant-restraints interaction in crash event. A case study has been explained in this paper to highlight the methodology.

Curtain airbag design offers protection in side crash and it plays a critical role in safety of the vehicle. Curtain airbag provides protection to the occupant in many impact events like frontal offset, side barrier, and side pole and rollover condition. For a vehicle to be safe for any side impact condition, the curtain airbag should deploy and take its final shape before any injury happens to the occupant. During deployment, it is important that the airbag chooses a path of minimum resistance and does not get entangled in interior trims. In reality, the trims always do obstruct the path of airbag deployment in some way. Hence, special care has to be taken care for designing areas surrounding curtain like providing hinges, deflector components etc. to avoid being caught. There are about ten different factors on this deployment is dependent upon. This paper discusses these factors and the effect of the factors on the trims and airbag development.