Time and temperature sensitivity of the hybrid III lumbar spine. Traffic Inj Prev 2021;22(6):483-488
Date
06/29/2021Pubmed ID
34180741DOI
10.1080/15389588.2021.1908543Scopus ID
2-s2.0-85110825197 (requires institutional sign-in at Scopus site) 2 CitationsAbstract
OBJECTIVE: Researchers have found a variety of uses for the Hybrid III (HIII) dummy that fall beyond the scope of its original purpose as an automotive crash test dummy. Some of these expanded roles for the HIII introduce situations that were not envisioned in the dummy's original design parameters, such as a relatively rapid succession of tests or outdoor testing scenarios where temperature is not easily controlled. This study investigates how the axial compressive stiffness of the HIII lumbar spine component is affected by the duration of the time interval between tests. Further, it measures the effect of temperature on the compressive stiffness of the lumbar spine through a range of temperatures relevant to indoor and outdoor testing.
METHODS: High-rate axial compression tests were run on a 50th percentile male HIII lumbar component in a materials testing machine. To characterize the effects of tests recovery intervals, between-test recovery was varied from 2 hours to 1 minute. To quantify temperature effects, environmental temperature conditions of 12.5°, 25°, and 37.5 °C were tested.
RESULTS: During repeated compressive loading, the force levels decreased consistently across long and short rest intervals. Even after 2 hours of rest between tests, full viscoelastic recovery was not observed. Temperature effects were pronounced, resulting in compressive force differences of 261% over the range of 12.5° to 37.5 °C. Compared to the stiffness of the lumbar at 25 °C, the stiffness at 37.5 °C fell by 40%; at 12.5 °C, the stiffness more than doubled, increasing by 115%.
CONCLUSIONS: A modest decrease in temperature can be sufficient to dramatically change the response and repeatability of the lumbar HIII component in compressive loading. The large magnitude of the temperature effect has severe implications in its ability to overwhelm the contributions of targeted test variables. These findings highlight the importance of controlling, monitoring and reporting temperature conditions during HIII testing, even in indoor laboratory environments.
Author List
Schmidt AL, Ortiz-Paparoni MA, Shridharani JK, Nightingale RW, Pintar FA, Bass CRAuthor
Frank A. Pintar PhD Chair, Professor in the Biomedical Engineering department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Accidents, TrafficHumans
Lumbar Vertebrae
Male
Manikins
Mechanical Phenomena
Temperature
Time Factors