Damage evaluation index of long-span spatial grid structure

Based on the double indexes of energy and displacement, this paper evaluates the damage of the structure, and puts forward a new dynamic damage index D value, which can classify the damage degree of the structure into four grades: basical intact, slight damage, medium damage, serious damage and collapse. In the form of structure, the long-span prestressed double-layer composite torsional reticulated shell is taken as the research object, and the two joints, three joints, four joints and six joints of the structure are respectively removed, including a total of six models. The equivalent load unloading method considering the initial conditions is used to analyze the collapse failure of the structure after removing the joints. The damage degree of the structure can be quantified by using the dynamic damage index D value of the structure, which is more conducive to the damage study of the long-span spatial structure.