توسعه و اعتبار مدل شبیه سازی کامپیوتری تصادف کردن صندلی چرخدار دستی بزرگسالان از جلو

Wheelchairs are primarily designed for mobility and are not necessarily intended for use as motor vehicle seats. However, many wheelchairs serve as vehicle seats for individuals unable to transfer to a vehicle seat. Subjecting wheelchairs to sled testing, in part establishes the crashworthiness of wheelchairs used as motor vehicle seats. Computer simulations provide a supplemental approach for sled testing, to assess wheelchair response and loading under crash conditions. In this study a nonlinear, dynamic, computer model was developed and validated to simulate a wheelchair and occupant subjected to a frontal impact test (ANSI/RESNA WC19). This simulation model was developed utilizing data from two frontal impact 20 g/48 km/h sled tests, which consisted of identical, adult manual wheelchairs secured with 4-point tiedowns, occupied with a 50th percentile adult male anthropomorphic test device (ATD), restrained with a 3-point occupant restraint system. Additionally, the model was validated against sled data using visual comparisons of wheelchair and occupant kinematics, along with statistical assessments of outcome measures. All statistical evaluations were found to be within the acceptance criteria, indicating the model's high predictability of the sled tests. This model provides a useful tool for the development of crashworthy wheelchair design guidelines, as well as the development of transit-safe wheelchair technologies.

The Americans with Disabilities Act (ADA) [1] has been instrumental for wheelchair users seeking transportation in motor vehicles. There is an estimated 2.7 million wheelchair users (2002) in the US [2], of which many travel in motor vehicles while seated in wheelchairs that may not be designed for this purpose. As a result, during a motor vehicle crash, these wheelchair-seated individuals are at a higher risk of injury than occupants seated in original equipment manufactured motor vehicle seats. In response to this problem, a voluntary industry standard was adopted that focused on improving the crashworthiness of wheelchairs used as motor vehicle seats (ANSI/RESNA WC19) [3]. This standard [3] specifies general design and performance requirements along with test procedures for wheelchairs used as seats in motor vehicles. In addition, WC19 requires a 20 g/48 km/h (30 mph) frontal impact sled test to evaluate the dynamic strength and assess the performance of occupied, forward-facing wheelchairs under crash conditions. This sled testing provides insights into the wheelchair and occupant loading and dynamics during a frontal impact that helps assess the wheelchairs crashworthiness. Additionally, the data acquired from such sled tests could facilitate design improvements and development of crashworthy wheelchairs, by studying shortcomings in current designs. However, dynamic testing requires the use of costly sled testing facilities, complex instrumentation and data logging systems in addition to costs associated with the purchasing of test wheelchairs and anthropomorphic test devices (ATD).

A computer simulation model (developed in MADYMO™) consisting of a an adult, manual wheelchair with a seated 50th percentile, adult male Hybrid III ATD subjected to a frontal impact 20 g/48 km/h (30 mph) (WC19 compliant) was developed utilizing test data from two identical sled tests. This simulation model was rigidly validated against the sled test data using visual comparisons of wheelchair and occupant kinematics, and six statistical assessments applied to all outcome measures. Statistical evaluations were found to be well within the acceptance criteria, indicating the model's high predictability of the sled tests. This model serves to provide a useful tool for the development of transit-safe (crashworthy) wheelchair technologies and wheelchair design guidelines by predicting response dynamics of the wheelchair and occupant under a simulated frontal impact.