| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 94 === Various systematic lumped-parameter models have been developed in recent studies for efficiently representing the dynamic behavior of unbounded soil. Those systematic lumped-parameter models are merely constructed by arranging several spring and damper elements, either connected in series or in parallel. Other than their applications in simplifying the analysis and design, those models have been also analogized to equivalent electric circuits according to their concise mathematical formulation and simple physical correspondence. Based on these new developments in simulating the lumped-parameter models with equivalent electric circuits, this research further consider the inclusion of foundation mass and superstructure to extensively explore the possibility of representing the simulation of a total soil-structure interaction system with a simple electric circuit experiment. Regarding the electric circuit experiment, the capacitor and resistor elements for corresponding to the spring and damper elements constituting a lumped-parameter model have been verified in recent studies. Therefore, the conductor elements in an electric circuit system for corresponding to the mass elements in a mechanical system needs to be additionally investigated such that the foundation and structural mass can be effectively incorporated. It is found that certain modifications are required in experimental arrangement since there usually exists an internal resistance for a realistic conductor and this value increases with the increasing value of capacitor. Moreover, a power amplifier is adopted for connecting with the function generator in this research to eliminate the noise contamination problem coming from insufficient power supply and the resulting insignificant output current. This serious problem encountered in the previous study is shown to be successfully removed. The focus of this research is to practically assemble the equivalent electric circuit representing a complete soil-structure system and conduct the experiment to compare its results with those from the relevant software simulation and mechanical system analysis. It is aimed in this study to consider the embedded square foundation system with selected parameters. The corresponding in-series lumped-parameter model is first determined and then analogized to an equivalent electric circuit. A foundation mass, a single-degree-of-freedom superstructure and a multi-degree-of-freedom superstructure are subsequently added to the lumped-parameter model for gradually establishing a comprehensive soil-structure interaction system for circuit simulation and experiment to validate its accuracy and feasibility. The comparison of the above results demonstrates that the error between the electric circuit experiment and the corresponding lumped-parameter model is normally below 10% and falls within the range of general engineering requirement. In summary, the effectiveness and accuracy of applying an equivalent electric circuit to represent the total soil-structure interaction system is confirmed.
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