GOALI: Dynamic Modeling and Analysis of Complex Systems with Application to Elevator Systems

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The main objectives of this project are to: i) develop a new substructure method that can accurately determine the dynamic response of complex systems involving taut and/or slack cables with variable lengths; and ii) theoretically and experimentally investigate the dynamics of elevator systems during normal operation and high-energy events. The proposed research integrates and advances five related research areas: distributed structural vibrations, cable dynamics, translating medium dynamics, flexible multibody dynamics, and elevator system dynamics. The substructure method exactly satisfies all the internal and boundary conditions, and the spatial derivatives of the dependent variables can be accurately determined. The method will be used with a new multibody dynamics method that uses Euler angles or Euler parameters, and the engineering strain, as the dependent variables for cables and beams with large deformations, which can significantly reduce the numbers of dependent variables and elements. The new methodology will be used to resolve the challenging system-level dynamic modeling and analysis problem for elevator systems, and experimentally validated at the Bristol test tower at the Otis Elevator Company. The demand for higher-speed elevators to service the transportation needs of higher-rise buildings requires accurate dynamic models of entire elevator systems to ensure that motion control performance targets can be robustly met, while achieving superior ride quality. As elevator codes are moving from ?prescriptive? ones to ?performance-based? ones, understanding the coupled dynamics between cables and lower-order dynamic components is a crucial step in architecting and optimizing these high-performance systems; accurately predicting internal dynamic states can reduce product costs and improve performance. If successful, this research will shift the elevator design paradigm from the current component-based approach to a system-based approach, and enable the design of ultra-high rise, high speed elevators being proposed for the next generation of skyscrapers. The methodology developed can also be applied to other systems such as cable robots, tethered satellites, and space elevators. The results from this research will be adapted for educational purposes to students at all levels. Simulations of elevator and other systems will be used in a summer educational program for underserved high school students in the Baltimore region. Underrepresented Meyerhoff scholars will be encouraged to conduct research in the PI?s laboratory and at Otis. An international conference series on the mechanics of slender structures will be organized to broaden the impact of the research to the scientific community.