Damage and/or Impact Absorber (Isolator) Movements Observed in Low Speed Crash Tests Involving Ford Escorts 940912
After an accident has occurred, there are a minimal number of low speed crash tests to assist the accident reconstructionist/engineer in determining the speed of a vehicle from little or no visible vehicle damage. Injuries are being documented by individuals as occurring in relatively low speed collisions. Yet, the impact speeds that have been taught to cause little or no damage do not suggest that injuries should have occurred at these correspondingly low G-forces. No comparison of the injury versus vehicle speed will be done in this paper; that is left to the biomechanical engineers and physicians. The purpose of this paper is to examine the issue of low speed impacts and the corresponding damage or shock isolator movement to the vehicle. For the purpose of this paper a low speed collision is an in line impact at a speed below 6 m/s.
Most available data from crash testing comes from the Department of Transportation (D.O.T.) sponsored Federal Motor Vehicle Safety Standard (FMVSS) compliance testing at 13.4 m/s21,92 and the New Car Assessment Program (NCAP) at 15.6 m/s. In 1993, Kerkhoff44 et al., enlarged the data base for the 1981-1985 Ford Escort crash test data. Barrier crash test speeds in that paper were conducted at 6.66, 8.88, 17.77 and 22.22 m/s with an unpublished test at 2.22 m/s. Kerkhoff44 also conducted a car-to-car crash test at 17.9 m/s.
To enlarge the data base for real world collisions, the authors conducted a series of 49 crash tests, using 1981-1985 Ford Escorts. Twenty crash tests involved a moving vehicle impacting a stationary vehicle at a speed range of 0.77 and 8.76 m/s. Twenty-nine barrier collisions were conducted at speeds from 0.4 to 4.26 m/s. The test data was reviewed to further examine the issue of the use of repeated crash testing in low speed collisions.