Development of a Preloaded, Force-Limited Passive Belt System for Small Cars

Development of a producible preloaded, force-limited passive belt restraint system for small cars has been completed at Calspan Corporation. The restraint system has been developed and evaluated through computer simulations and sled tests. This paper presents and discusses the results of the developmental program at velocity changes of 34, 40 and 45 MPH during symmetric frontal barrier crash sled and computer simulations with regard to the effect upon 50th, 95th, 5th percentile and 6 year old sized anthropometric test devices (ATDs). Data obtained include head and chest triaxial accelerations, femur loads and belt loads for the ATDs. High speed movies allowed comparisons of ATD kinematics during the sled tests with ATD model kinematics obtained from the computer simulations.

A commercially available belt preloader was used during the sled tests along with: nylon webbing, polyester webbing and two levels of force limiting webbing. The system was also evaluated using a force-limiting active lap belt and these results are compared with non-preloaded, standard webbing belt system responses.

Results of this experimental and simulation study demonstrate that the FMVSS 208 performance evaluation criteria are met at 45 MPH velocity change for the 50th percentile ATD right front passenger and at lower speeds (but greater than 30 MPH) for other adult-sized right front passengers. Compliance of a 50th percentile driver is also demonstrated at 34 MPH.