Research On Damage Identification Of Spatial Steel Structuer Based On Internal Force Redistribution Law

Structure damage is random and uncertain.However,the sensor can only monitor the damage of the arranged position,and the number of the sensor are limited.It cannot cover the spatial steel structures with many members,resulting in the failure to identify the damage in the unmeasured location in time.After the structure is damaged,the internal force of the member will be redistributed,and the internal force redistribution mode has a certain regularity with the change of the structural damge state.Therefore,this paper proposes a method for damage identification of space steel structures based on the law of internal force redistribution.By exploring the law of internal force redistribution,the relationship between the measured member and the damaged member is established to realize the indirect identification of the unmeasured member damage.The main research work of this article starts from the following three aspects:Determining method of internal force redistribution law based on graph theory Dijkstra algorithm.The structural response parameters,which can reflect damage effects in the algorithm,are constructed and structural graph theory model is establish according to the connection mode between structural members and nodes.Through the position of the affected members,the damge affected area in which boundary the vertex pairs are selected according to certain principles is determined and the shortest paths are get.Based on this,the shortest paths are classified and screened in order to analyze its change law under different damage conditions which is used to characterize the internal force redistribution law.To verify the validity of the proposed method for determining the redistribution of internal forces based on the graph theory Dijkstra algorithm,the change law of the shortest path of the single-layer spherical reticulated sheel under different damage states is analyzed and the relationshop between the multi-overlapping of the shortest path and the damaged member is established.Research on the internal force redistribution law of structural damage deterioration.Considering the effects of different degrees of wind load and multi-stage damage development on the law of internal force redistribution,based on multi-load conditions and multi-stage damage,the structural response parameters containing both the damage effect and the load effect and the structural response parameters of staged damage are constructed respectively.According to the change of the response parameters,the shortest path edge weight and the multi-overlapping memebers,the change of the internal force redistribution is analyzed after considering the wind load and damage development.Taking the single-layer spherical reticulated shell as an example,the applicability of the method for determining the internal force redistribution law is explored.Research on structural damage identification based on internal force redistribution law.The sensors are arranged to indirectly identify the damage of sensitive members which are sensitive to geometric defects and determined according to the sensitivity index.The damage simulation is performed on the sensitive members and different degrees of wind load are applied,based on which the multi-overlapping members are determined by the internal force redistribution law.The multi-overlapping members that are repeated many times under different load condition are select as the sensor placement position.Combining the damage location indicators,the sensors are grouped to establish the connection between the tested member and the damaged member to realize the indirect location and quantification of the sensitive member which is unmeasured.