Optimum design, finite element model updating and dynamic analysis of a full laminated glass panoramic car elevator (Conference Paper)

A systematic optimum design procedure, including an accurate dynamic analysis of a full glass panoramic car elevator under real dynamic load conditions are presented in this work. The cabin is manufactured entirely of laminated glass (two glass layers and an interlayer of polivinyl butiral-PVB), except the roof and the platform. First, modal identification and structural model updating methods are applied, leading to develop high fidelity finite element model of the glass and its connection subsystems. The identification of modal characteristics of the glass is based on acceleration and stress time histories, which are obtained through an experimental investigation of its dynamic response, in two different states. First, in a support-free state by imposing impulsive loading and second in a fixed-free state by imposing random excitation with the use of an electrodynamic shaker. Single and multi-objective structural identification methods are used for estimating the parameters (material properties) of the FE model, based on minimizing the deviations between the experimental and analytical modal characteristics. Next, a "mixed computational-experimental" analysis method is applied, in order to simulate accurately the dynamic behavior of the complete elevator system, in emergency situations like safety gear engagement. A series of experimental tests were performed under real operating conditions, using an experimental device that was designed exactly for this purpose and aimed at recording the acceleration time histories at the connection points of the frame with the safety gears. These acceleration time histories are subsequently used as base excitation for the FE model of the complete elevator system and the stresses developed under these specific loading conditions are evaluated. On the basis of these numerical results, the critical points of the frame are selected, as corresponding to larger stresses and an optimum design procedure was applied. Finally, in order to test the reliability of the method applied, strain gauges are placed at the critical points of the optimum designed system and a series of measurements are carried out, in order to experimentally verify the developed stresses. Direct comparison of the numerical and experimental data verified the reliability and accuracy of the methodology applied.