Design And Study On The Test Facility Of Multi-directional Loading System For The Joints Of Spatial Structures

With widening application of large-span spatial structures, load-carrying performance of spatial joints has become a focus in research and the structural experiment proves to be an efficient method to study joint performance. Traditional load applying methods are simple with little automatization, and most are done only on the plane so that complex spatial joint experiment is hard to achieve. Therefore, it is necessary to develop an intellectual experimental facility that can apply load on test joint in all directions in order to obtain a comprehensive understanding of the performance of various spatial joints.First of all, the paper introduces an experimental system of multi-planar joint, by which convenient loading in all directions can be realized and accurate simulation of the force received by the joints can be accomplished so that the complicated experimental requests can be met.Second, a global-shaped experimental load-carrying structure is designed as the load-carrying facility in the experimental system of multi-planar joint. To deal with the intricate loading in the experiment, structural optimizing theory is applied and programs are written, which enables the researcher to find out the most unfavorable loading combination for the global-shaped experimental load-carrying structure, and to make the parameter analysis before deciding the dimension of the load-carrying structure and finally calculating the strength and stiffness of it as well as its maximum load.At last, the paper presents a module specially programmed for the system in finite element software ANSYS, which helps to model the test joint, to apply load, to conduct elasto-plastic finite element analysis and to process computation results, to test the strength of load-carrying structure, so as to realize numeric simulation of the whole process of joint test.