Curtain Airbag Design Process Optimization

Airbags are essential parts of passive safety systems in current vehicles. Today´s growing vehicle market diversification in major segments and increasing numbers of sub-segments with a wide variation in roof line designs result in a high number of different airbag designs. Each vehicle model needs its individual design parameters like airbag cushion shape, chambering, and inflator performance. Hence effective processes are required to develop these variants within the given short timeframe. This paper shows how development cycles for curtain airbags can be reduced using a HyperMesh based Tcl/Tk macro. Traditionally, the development process to derive bag designs in early phases of projects starts in the design department with an initial proposal for the airbag shape. A CAD drawing is build up and passed to the CAE engineer who creates a CAE model and evaluates the design by standard simulation tasks using a finite element solver. The design is optimized in close interaction between designer and CAE engineer. Finally the optimized design is returned back to CAD department where the drawing is finalized. To further optimize these loops, a macro has been established in order to allow engineers in the design department to define airbag designs without loops with the CAE department. Since the basic simulation task at the beginning of the development process can be standardized, the routine work of the CAE engineer can be replaced by a macro, i.e. the designer performs standard simulation in the early project phase without required knowledge of the finite element solver by applying the macro. The macro leads the design engineer step by step through the setup process, creates the simulation input deck and launches it automatically to the computing cluster. After post-processing, the designer can directly start optimization loops without interaction to a CAE engineer. Thus, a more efficient process to define early phase airbag designs has been developed, that can free up CAE resources for the more challenging performance driven fine-tuning in the overall vehicle restraint system at later project phases.

The Author

Dr. Jörg Büttner
Team Leader CAE / Simulation Airbag Components
TRW Automotive GmbH
Occupant Safety Systems
Motor Vehicle Manufacturer
Industriestraße 20
73553 Alfdorf, Germany