The Similarity Study Of Steel Beam-to-column Connection Models

Model test is a widely-used means of structure engineering research, and its reulst could be used as the reference of engineering-oriented desining. However, there still lacks systematical study among different-scaled beam-to-column connections at present, and simulation error analysis is also missed when converting model-testing data to that of prototype. Therefore, the present study, as a subproject of"the standard research methods in property study of frame connections"supported by National Natural Science Funds (No. 50678098), focused on the model testing of steel beam-to-column connections from three aspects of theoretical analysis, experimental study and finite element analysis respectively. The present research work mainly included four items of the deduction of similarity condition of beam-to-column connections, the comparison of the methods of model designing, the analysis of the similarity of different-scale models and the analysis of simulation error between the model and the prototype, aiming to find out the main factors influencing the simulation error and to figure out the law of its influence.In the present study we analyzed the model test of simply supported beam theoretically, and then compared the respective simulation error of two different methods of model designing while further analyzing the reasons for their occurrence, based on which we recommended possible model design for bend structures. And we additionally deduced the similarity condition of steel beam-to-column connections according to the principle of similarity and dimensional analysis. In model test of steel beam-to-column connections, we designed three T-shape connections according to the similarity condition for the present study, in which beam and column had the same sections. The biggest one was used as the prototype, while the other two smaller ones as models in scale of 0.706 and 0.563 respectively. The experiment was carried out in the manner of constraining column end by pinned support and forcing static load on the free end of the beam. Then the similarity among models and the prototype were all studied in aspects of stress, displacement, general characteristics of shape changing and damage mode. Especially, simulation error of stress and displacement among models and prototype was analysed.In finite element analysis, we constructed four groups of non-linear models using ABAQUS software and then studied the similarity of both stress and displacement on different testing points under multi-step loading force occurring in the four different model-designing methods. Thereafter we acquired simulation errors and their changes, and further study influencing factors of simulation error and the responding laws.Both experimental results and finite element analysis showed the following conclusions. The thickness of the model would be the main reason for the occcurance of simulation error. Additionally, the boundary condition and material properties would produce simulation error as well. The simulation errors would change due to different loading process and different testing poits. Based on these results we finally gave out some suggestions of model test.