The Study Of Morphogenesis And Mechanical Behaviors Of Reciprocal Structures

With a long history and unique configuration, reciprocal structure has recently been a new academic interest receiving considerable attention for its characteristics of simple connection, low construction technology, fast assembly and attractive appearance. A simple reciprocal structure applies well to temporary building while a carefully designed one can realize safety, robustness and serviceability as well. Yet current studies on reciprocal structure so far are not enough to guide its engineering application. Plus, only a few reciprocal systems such as the Davinci Grid and Rainbow Bridge have been explored. Therefore, further research is expected to discover more possibilities of reciprocal structure. The thesis introduces the historical development and proceedings of reciprocal structure, investigates its practical design based on form and mechanical property via graphic theory, mechanism analysis, optimization method and numerical simulation etc.As regard to morphogenesis of reciprocal structure, a planar transformation method was proposed based on Archimedean tiling, the method for structural determinacy was complemented. Mathematical formulation was established to unveil the relationship of structural form and customized parameters. Genetic algorithm and gradient-based optimization method were compared for the morphogenesis efficiency under certain parameters. Also, a fitting strategy for target free-form reciprocal structure was studied in that its final shape was unpredictable through parameterized morphogenesis. Basically, the research resolved the modeling problem of reciprocal structure that beyond the ability of traditional CAD software.On the other hand, mechanical properties of planar and spatial reciprocal structures were studied and compared with traditional ones under different load conditions. Calculation formulas for the internal force of planar determinate reciprocal grid were given. Reciprocal structure is non-hierarchical with more uniformly distributed force while its displacement distribution is similar to common structure. Adequate constraints are required for the reciprocal structure with quadrilateral grid to prevent inextensional mechanism and the addition of diagonal components can enhance its anti-deformability. Moreover, reciprocal structure has lower natural frequency and thus is more flexible than common structure. Vibration modes are similar between reciprocal and corresponding non-reciprocal structure, and specifically, the first three orders of vibration modes are mainly global vibrations.The research outcomes can be used to expand the types of reciprocal structure which is beneficial to its design exploration. Conclusion about its structural properties also contributes to deeper understanding of reciprocal structure, laying the foundation for the promotion and engineering application of this special structure.