Research On The Mechanical Behavior Of Cast Aluminum And Cast Steel Bolted Connections In Spatial Reticulated Shell Structures

The reticulated shell structure is a type of spatial structure in the ascendant with the characteristics of high rigidity, light weight, beautiful shape and better technical and economic indexes, which make its application range increasingly wide. In order to assemble all the members into the reticulated shell structure and make them work together, the key point is the connection details.Exhibition Greenhouse of Shanghai Chenshan Botanical Garden project is a single-layer aluminum reticulated shell structure. Exhibition Greenhouse of Singapore Botanical Garden applies the hybrid steel structural system of arch and reticulated shell structure. New types of joints: the cast aluminum joint and the cast steel joint are proposed by a company in these two engineering projects. Because the two types of joints are self-developed, the finite element analysis (FEA) and experimental studies on these joints are necessary to investigate the mechanical properties and ultimate loading capacities, and also verify the accuracy of the finite element analysis.This research is conducted based on the finite element calculation, theoretical analysis and the experimental studies of the mechanical properties of the cast aluminum joint and cast steel joint. The main research contents are listed as follows:(1) Through the full scale testing and FEA method, the mechanical property and failure mechanism of the new cast aluminum joint under 3 typical loading cases are investigated, and the comparison of the experimental results with the FEA results is conducted to verify the accuracy and reliability of the finite element analysis of the cast aluminum joint.(2) The stress concentration factors of the critical section are obtained from the elastic analysis by using the verified FEA model for the cast aluminum joint, and the design methods and design formulas for the carrying capacity of the cast aluminum joints are proposed for the engineering application, which are verified by the experimental results of the cast aluminum joints under the 3 typical loading conditions.(3) The full-scale static loading test and non-linear FEA for the new cast steel joint are conducted. The bearing behavior and failure mechanism of the cast steel joint are studied and the accuracy of the FEA model is verified by the test. Based on the comparison between the test results and FEA results, it can be found that the multilinear hardening plasticity material constitutive model is better than the commonly used ideal plastic one to simulate the tests.(4) The elastic finite element analysis of the cast steel joint under a variety of loading cases is conducted by using the verified FEA model. On the basis of the FEA results and test data, the simplified design methods for the carrying capacity of the cast steel joint under combined loads are proposed.The researches and conclusions above can provide some theoretical guidance and reference value for the design of the cast aluminum joints and cast aluminum joints, and can promote their applications in the reticulated shell structures.