Dynamics of systems operating in coupled motion environments

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Many articulated dynamic systems operate in essentially-prescribed motion environments. This means that though the entire system is theoretically dynamically coupled, in many cases due to differences in energy and momentum, subsystems of interest can be considered to be influenced by the larger system but not to have significant impact upon it. Examples of such prescribed motion systems include an aircraft secured to a ship's flight deck, a shock-mitigating suspension seat used on high-speed marine craft (HSC), and a neonatal patient being transported in an emergency vehicle. In such examples, the effectively-prescribed motion of the larger system (ship/boat/ambulance) provides the primary dynamic excitation of the much lighter system. Other influences, such as aerodynamic loading and force coupling between subsystems, also can affect the system dynamics and can be influenced by the motion of the larger system. Investigation of this class of problem is the subject of the applicant's continuing NSERC-funded research programme. While initial projects focused primarily on shipboard systems, recent involvement with non-maritime systems has confirmed that significant opportunities exist to efficiently adapt what has been learned to other similar environments. As an example, there appear to be close parallels between previous work and the dynamics of neonate patient transfers in both air can ground ambulances. As a result, the current proposal is aimed at continuing or completing some previous work; but importantly also extending it to other applications where operation of dynamic systems in motion environments is essential but hazardous. The time-dependence and nonlinearity of forces acting on these systems render traditional static, quasi-static, and frequency-domain approaches inadequate for understanding the true nature of the dynamic interfaces. Rigorous analysis relies on the fusion of principles from multibody dynamics, vehicle dynamics, structural analysis, transient computer simulation, statistical analysis, and aerodynamics. This continuing research programme is developing and validating computational tools and applying them to improve understanding of these complex dynamic systems. Categories of systems considered are rigid-body, flexible-body, and human biodynamic systems. The approach will remain consistent with recent work and continue to involve theoretical, computational, and experimental components. The proposed research is intended to contribute to improving the safety and operability of people and equipment operating in motion environments. Through training of HQP, engagement with the end-users of the research, open publication of research outcomes, and involvement with far-reaching organizations such as the International Working Group on Human Performance at Sea, efforts will continue to be made to maximize the positive impact of this research and maintain Canadian leadership in the areas of investigation.