Of Extended Finite Element Analysis Of The End Plate Semi-rigid Composite Joints Mechanical Properties Of The Factors

With its advantages of high carrying capacity, good ductility , good seismic performance, and convenient construction, composite structure has applied to various construction fields, and be used to in-depth studies. Current composite structure components mechanics research comes to relatively mature, but the joints research is relatively juvenility. In traditional joints design of framework, the connection among components is assumed as perfect rigidly connection or hinged connection. But a large number of practical projects had shown that the connection of beams and columns in composite structure is between rigidly and hinge connection. So it should be regarded as semi-rigidity composite joints. A semi-rigidity composite joint has advantages of large deformation, good ductility and strong capacity of energy dissipation. It improves the power of statically indeterminate structure, and constructs conveniently, and uses strength of material fully, and has benefited economic characteristics. However, because semi-rigidity composite joints perform complex mechanics, any changes of structure will affect the performance of joints.Therefore, the author has done a lots of research and literature review about semi-rigidity composite joints, summed up current research status of semi-rigidity composite joints, connection form, and analysis models, established a finite element models of semi-rigidity composite joints with endplate models, using of finite-element analysis software ANSYS8.0, analyzed the effects of concrete slab thickness, strength, and pre-stress on bolt, friction impact on the initial rotation stiffness, plastic limit moment, and plastic limit corner, based on correctness of model certification.Through research, the author makes conclusions as following:(1)When the thickness of concrete slab increases, the initial rotation stiffness, plastic limit moment, and plastic limit corner of Semi-rigidity composite joints increase.(2) When the compression and tensile strength of concrete slabincreases, the initial rotation stiffness, plastic limit moment, and plastic limit corner of Semi-rigidity composite joints increase.(3)Because the Pre-stress of blots conduce the initial corner of composite joints, in order to compare the performance of different Pre-stress of blots of composite joints, it needs to eliminate the initial corner in calculations. When the Pre-stress of bolts increases, plastic limit moment and plastic limit corner of Semi-rigidity composite joints decreases, and the initial rotation stiffness increases a little,(4) When analyze the friction between flange column and endplate by only, the elastic limit corner, the elastic limit moment, and the initial rotation stiffness of Semi-rigid composite joints remain unchanged, but it makes insignificant effect in plastic limit moment and plastic limit corner of Semi-rigidity composite joints.(5) When the friction between flange column and endplate and the Pre-stress of blots work together, the initial rotation stiffness of Semi-rigid composite joints increased significantly, but the plastic limit moment is insignificant.