Crashworthiness of wheel-chaired occupants with restraint system for real-life crash scenarios of mass transit buses
The aim of this research was to study the behavior of a wheel-chaired occupant for different crash scenarios in a mass transit bus. Actual crash sled tests were carried out at the National Institute for Aviation Research (NIAR) crash laboratory facility and validated according kinematics and injury parameters. Setup of these crash tests was done by following various wheelchair restraint and tie-down standards. Other factors, such as wheelchair placement in a bus environment were taken into consideration while preparing the sled tests. The Hybrid III 50th percentile anthropometric test device (ATD) was used for all crash pulses, as it represents the weight and size of an average American. A detailed Computer-Aided design (CAD) model using CATIA V5 was created by applying a reverse engineering technique. This CAD model was then used to prepare a detailed finite element model (FEM) and a facet model which were used for carrying out simulations with the help of software such as MADYMO for multi-body dynamics and LS-DYNA for finite element analysis. These two models were then simulated for the same crash pulses as the actual sled tests to study the kinematics and injury parameters. To define correct material properties tension tests of the belt material were carried out to obtain the actual belt webbing characteristics. The detailed finite element model was developed and used to study the exact force-displacement relationship and to obtain the proper kinematics. Simulations were run using both software for all crash tests, and the kinematics and injury values were validated with the actual crash test values and kinematics. Validation was done using the Motion View software. The validation of the tests was studied to discern the various parameters responsible for the injury values of the wheel-chaired occupant. Further, a more detailed parametric study was carried out where these parameters were changed or modified to create combinations of restraint and securement systems, in order to provide an overview of the appropriate choice of restraint and securement system to reduce the potential injury to the wheel-chaired occupant.
Thesis (M.S)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering