Abstract
ABSTRACT
The modeler is faced with an extremely difficult task. Like with the development of any new concept, it must start from the simple and gradually build to the complex in a systematic ground up approach. There are two goals that provide a basis for constructing this model:
1. At each stage of development, no matter how simple or complex, the model must be able to be integrated into a full-scale crash simulation. If the model cannot do this then it loses value as an engineering tool.
2. The model must be constructed in a way such that more detailed component models can he easily transitioned into a base model.
With the goals in mind, the development of the occupant model and its components can be divided into five stages, level 1 to 5, based on the level of detail in the model. Issues addressed at each level of the model concern geometric and physiological representation.
Geometric representation includes the shape of the mesh, the mesh density, and to what level of detail will objects be included in the model. The physiological representation includes material properties, joint modeling, failure and injury modes, and environment interaction.
It is not necessary for the whole body model to be constructed of components from the same level of development. A model may contain a level 1 head and neck, with a level 4 thorax, and level 3 legs. This discretion will be left to the modeler and is dependent upon certain issues. These include, but are not limited to:
1. Certain aspects or safety devices being studied will not require a detailed complete body and may only need a detailed component. For example, the effects of a new airbag and seat belt system will need a more detailed upper body model rather than the lower portion. It is in the interest of computational time and cost to limit a model to the necessities for the particular study.
2. It may not be possible to have models developed for all components that are of the same level. Limitations on the scientific data available will preclude the modeler from developing higher-level models of certain segments. As an example, it is much more difficult to model major organs than it is the knee joint; therefore, a level 5 knee is likely to be placed in the model before a level 5 heart and lungs is available.
In all cases, however, geometric compatibility must be preserved to ensure a good interchangeability between various segments.