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Flaws in Malibu I and II interpretation of test results that have influenced many poor rollover roof designs

Abstract – The majority of recorded world rollover accidents show the final roof deformation to be characterized by catastrophic intrusion into the safety cell. This roof collapse mechanism is still the subject of intense debate as to whether occupant fatalities, severe injuries such as quadriplegia, paraplegic, and brain injuries observed in some occupants after rollover are the consequence of roof intrusion.

This paper for the first time proves that there is a causal relationship between roof intrusion and Injuries sustained by occupants. To achieve this solution, it was necessary to revisit the Malibu I and II rollover experimental tests carried out by General Motors more than 20 years ago. Using forensic methodologies with simple mathematical operations, it was shown that the original Malibu I and II interpretations of experimental test results were flawed because test engineers misunderstood the results they had obtained from the conducted tests. The Malibu I and II results themselves prove that there is a 100% causal relationship between the high neck loading that was recorded by the dummy’s neck and the roof intrusion.

In order to prove that is the case, the famous Figure 13 in SAE paper 902314 [10] that gives roof crush and neck loading with respect to time was digitised for the first time and the roof crush curve differentiated twice to obtain the roof acceleration characteristic. This roof acceleration curve shows to have peaked at precisely the same time as the peak neck loading and at this same time the roof was intruding into the safety cell at a rate of 1.952 mph. Finally the proof has been derived; unfortunately, this has come more than twenty years later after which all cars with poorly designed roofs on the roads today have based their roof design philosophy on the misinterpreted Malibu results and conclusions.

Keywords: Roof crush, rate of intrusion, crashworthiness, Malibu I & II tests, load path, collapse mechanism, head and neck injuries, rollover

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