This research examines the effects of impactor characteristics on the calculated structural stiffness parameters A and B for the struck sides of late-model vehicles. This study was made possible by crash testing performed by the National Highway Traffic Safety Administration involving side impacts of the same vehicle line with both a rigid pole and with a moving deformable barrier. Twenty-nine crash test pairs were identified for 2018 model-year vehicles. Of 60 total tests, 49 were analyzed. Test data for 19 vehicles impacted in both modes resulted in A and B values considered to be valid.
Classifying these 19 vehicles according to the categories defined by Siddall and Day, only Class 2 multipurpose vehicles were represented by enough vehicles (10) to search for trends within a given vehicle category.
For these vehicles, more scatter in the results was observed in both A and B values for the MDB impacts compared to the pole impacts. A causal relationship between stiffness values in the two test modes was not discovered. In either test mode, there was little correlation between either A or B with vehicle wheelbase.
These studies confirm previous findings; namely, that the side structure stiffness parameters vary widely, even within a given class, and that they cannot be predicted based on other vehicle characteristics or other test modes.