Search Results

Numerical simulation of the airbag can be used as a powerful tool in the development of a SIR (Supplemental Inflatable Restraint) system leading to an optimized design and to reduce the development time. However, modeling flattened or folded airbags from the 3D CAD geometry and simulating exact airbag shapes during the deployment is a very complex problem. Especially for the passenger side airbags, generating a flattened and folded mesh from the CAD geometry of the airbag is a very difficult task as these airbags are made of non-developable surface and can not be flattened easily without introducing secondary folds, wrinkling or distortions of mesh. A novel approach called as Initial Metric methodology effectively addresses these problems. The initial metric method uses two types of meshes, A CAD reference mesh and a mapped or a scaled (compressed) mesh constructed from a CAD mesh of the airbag. In the simulation, mapped or scaled (compressed) mesh is used for airbag inflation.

Modeling and simulation are becoming increasingly popular to help develop restraint systems and enhance the value of the design. Various types of tests are being developed and used extensively in evaluating and optimizing the performance of restraint systems by both OEM's and system suppliers. The use of analytical tools along with laboratory testing can help improve the effectiveness and the speed of developing and implementing a restraint system to maximize the occupant protection. The side airbags are used in conjunction with energy absorbing foams to manage the energy transfer to the occupant from the structural intrusions in a side impact. The requirement of deployment times are shorter in side impact than in a frontal impact due to the limited space between the occupant and door structure.

This work describes the development of a three-dimensional finite element model of the human arm. Mechanical properties of the arm were determined experimentally for use in the model development. The arm model is capable of predicting kinematics and potential injury when interacting with a deploying airbag. The arm model can be easily integrated with available finite element and rigid body dummy models. This model includes the primary components of a human arm. It includes all the bones of hand, ulna, radius and humerus. Anthropometry, moment of inertia, joint torque and tissue compressive properties were determined experimentally from human cadaveric subjects. To calibrate the model, both free-swinging motion and pendulum impact tests were used. The global responses of the pendulum force, pendulum velocity and the angle of rotation time histories of the arm were obtained and compared reasonably well with the experimental data.