Examining the Relationships Among Injury Outcomes, Velocity and Grip Strength During Dynamic Platform Perturbation
Date of Award
Master of Science (MS)
Harris, Gerald F.
Studies examining the relationship between inputs and outputs for simulated models of dynamically perturbed horizontal platforms are scarce. Most of these scenarios include a standing operator with upper extremity grip, oftentimes subjected to lateral impulses, which may lead to occupant injury. While the detailed study of these collision scenarios is sparse, the prevalence of their application is great.
This thesis aims to identify how two input parameters, velocity change (ÄV) and grip strength, affect injury assessment reference values (IARVs). This is accomplished by using Mathematical Dynamic Modeling (MADYMO) software to simulate the scenarios defined by those inputs. In the simulation, an anthropometric test device (ATD) representing the operator is placed in a streamlined quadrilateral model (SQM) representing the dynamic horizontal platform. The SQM is subjected to a deceleration impulse which arrests its motion, causing the ATD to fall and sustain injury.
Results from the series of collision scenarios lend themselves to a modified quadratic regression which adequately predicts head injury criteria (HIC), head angular velocity, neck injury criteria (NIC) shear in the positive direction, and NIC-bending in the negative direction. Quantitative analysis of IARVs shows that high grip strengths tend to protect the occupant from injury, while higher ÄVs do not necessarily correlate to injury exacerbation. Visual examination of the collision series at high ÄVs show the ATD being ejected from the SQM, rebounding off the ground, and rolling onto its back. Following from the visual results, it can be concluded that translational movement parallel to the ground and anterior-posterior impacts to the ATD reduce injury. Ejection from the SQM cabin is not correlated with injury reduction because trials where a lateral constraint (door) was present showed dramatically reduced IARVs at the highest ÄV and lowest grip strength condition.