Grid Structure Welded Hollow Spherical Joints Damage Detection

Because of good earthquake-resistance，flexible structure form and other advantages,spatial structure is widely used in industry and civilian construction. Therefore, spatialgrid structure has been rapidly developed at home and abroad as the main form oflarge-span building roof. Due to natural disaster or design, construction and other reasons,spatial grid structure causes structural damage, the collapse of the structure, and evenserious engineering accident in the process of the employment. In order to reduceengineering accidents and avoid casualties and property losses, identifying and handlingthe structural damage timely has become a hot issue of research at home and abroad.Through the theoretical analysis in combination with the specific engineering, thethesis focuses on the following researches. It includes:1) It checks the actually placed four square pyramid space grid structure in Hebei,then takes corresponding measures dealing with the problems found in the examination inaddition with the demonstration of construction technology and method of reinforcement.2) With the aid of the laboratory equipments, the thesis makes the dynamic modaltesting concerned with the actually placed four square pyramid space grid structurebefore-and-after the reinforcement. It compares the structure data before and after thereinforcement. The result shows that the frequency is increased significantly after thereinforcement, illustrating its good effect.3) With the finite element analysis software ANSYS, the thesis builds the finiteelement model of the grid. Moreover it summarizes the methods of simulative nodedamage and selects node injury equivalent methods for reducing the stiffness of the rodend node connected to the rod of the finite element. With the employment of the strainmodal difference as parameters, it identifies and locates the node damage of structuralfinite element model.