Dc. Viano, COMPARISON OF ARM UP AND DOWN IN SIDE IMPACTS WITH BIOSID AND DIFFERENT ARMRESTS, Journal of biomechanical engineering, 116(3), 1994, pp. 270-277
BioSID dummy tests were run with the arm down at the side during loadi
ng of different armrests in simulated side impact crashes. The Hyge sl
ed tests duplicated previous studies of BioSID with the arm up, SID, a
nd animals. When the BioSID arm is against the side, the arm extends f
rom the shoulder to the bottom of the third rib and has a steel shank
covered by foam and vinyl. Loading through the arm transfers force to
the three chest ribs and shoulder. In comparison, direct armrest loadi
ng of the chest or abdomen primarily involves a single rib and substan
tial rib deflection, when the armrest crush-force exceeds the strength
of the rib. The Viscous response in BioSID showed the greatest differ
ence of all criteria for the arm up or down. The response of the third
rib correlated with injury risks determined from animal tests using t
he different armrest designs in a simulated high position. While injur
y data are not available for the arm at the side or for the armrest in
the low position, the STIFF armrest may cause injury when the arm is
not at the side and the armrest loads the liver and spleen. R ib defle
ction in BioSID showed the protrusion of the STIFF armrest into the ab
dominal region in both arm positions, because the loading was below th
e arm even in the down position. However, the arm extends laterally so
it involves the upper ribs earlier than in the arm-up condition where
more space is available. Torso deflection showed similar maxima with
the arm down and a high armrest position, because the bridging action
of the arm and shoulder increases the stiffness of the dummy. The armr
est designs cover a range in crush characteristics for occupant protec
tion systems based on experience with other interior safety features,
knowledge of human tolerance, and results of injury in animal tests. T
he SOFT design was most appropriate for interior use. The STIFF design
produced serious injury in companion tests with animals, and the BioS
ID correctly assessed injury risk by peak rib deflection or Viscous re
sponse when tested similarly. In contrast, SID and TTI(d) did not indi
cate injury risks or safety performance. The current study indicates t
hat response differences can be expected with arm placement, and BioSI
D can assess safety implications of different armrest types and arm pl
acement.