The Method For Dynamic Analysis On Reticulated Shell Considering The Elastoplasticity Of Welded Hollow Spherical Joints

The research on joints'behavior focused on semi-rigid joints. The research on effect of joints'behavior on structures was early at steel frames field and can trace back from the early 20th century. A lot of domestic and international research results have been gotten on the rotation capability of joints and the static and dynamic behavior of steel frames with semi-rigid joints. Their theory is also mature.In contrast, the research on effect of joints'behavior on reticulated shell is little. The research on rotation capability of the joints mainly rests on elastic range. At present, the research on effect of joints'behavior on reticulated shell is mainly centered in the static and global stability respect. Our country is a seismically active area, so, with the more and more applications of large-span reticulated shell structures, the research on dynamic capability of reticulated shell considering the joints'behavior and more accurately analyzing the seismic behavior of reticulated shells are particul- arly important. Welded hollow spherical joints are common in single-layer shell structure. It is thought that the joints are completely rigid in common while not in fact. Their elastoplasticity must have impact on structure and have to be paid much attention to.The development of reticulated shell is reviewed and the research on the joints'rotation capability and their effect on reticulated shell are summarized in the paper. Welded hollow spherical joints'basic forms and theory are also described concisely.Existing models of joints'were based on the semi-rigid beam-column joints of steel frames and had many limitations, so they were not suited to welded hollow spherical joints. Thus, by finite element method and finite element software ANSYS 11.0, a series of data analysis and generalization were provided and the bilinear model of loading-deformation curve was established finally in the paper.Then, short-member model considering the elastoplaticity of welded hollow spherical joints which can analyze the elastic-plastic behavior of joints is presented. To K8 reticulated shell with welded hollow spherical joints, for example, the model is successfully imported to finite element software SAP2000. The dynamic elastic- plastic behavior of reticulated shell considering the joints'elastoplasticity is analyzed. The free vibration characteristics and the law of the elastic-plastic seismic response of reticulated shell considering the joints'elastoplasticity are revealed in the paper .The behavior of reticulated shell considering the joints'elastoplasticity and based on the assuming of rigid joints are compared. The results show that the actual behavior and work performance of the reticulated shell can be analyzed accurately through the calculation model considering the elastoplasticity of welded hollow spherical joints.