Study On Damage Identification Of Grid Structures Based On Dynamic Fingerprints

The whole rigidity of the spatial truss structure is good, and the technical andeconomic index is superior, so they are widely applied to the public buildings in largespan. During the long active service time, the structure maybe presents all kinds ofdamage because such tired accumulating. If the damage can not be found in time, it willcause the expansion, so it is very essential to identify damage in the structures in time.To the simple structures, some riper methods of damage detection have existed. But tothe large-scale complicated structure such as the spatial truss structures, because of allsorts of difficulty, the existing methods are difficult to apply to the actual engineeringstructures. Emulational modal of the grid structure is carried out，the major researchresults include:This paper studies the diagnosis of structural damage theories and discusses theirmerits and faults based on dynamic fingerprints.Describing the possibility of applying COMAC to damage identification of gridstructures.Based on the characteristics of elemental modal strain energy,the concept ofsensitive mode shape and an algorithm for its determination is presented. The changerate of sensitive elemental modal strain energy as the labeled amount was selected andapplied to structural damage detection.An evaluation algorithm based on the structureflexibility is given. From the above analysis, we educe that the two-step damageidentification method.An modal is devised to test the former method.Elaborating the simplication methodto analyze grid modal.The theory has been derived,which consists of element stiffnessmatrix,transfer matrix,assembled matrix.The self-vibration characteristics of grid structure is summarized to make preparation of emulational analysis.The modal analysis of the grid structure is developed by means of ANSYS fromthe finite element command. The damage of measured grid under various conditions canbe simulated via parameter adjustability.8damage condions are raised based on possibledamage.The numerical results show that COMAC can reduce the scope of damagedelements.Taking advantage of ZDAC to choose sensitive mode shape,this paper uses thechange rate of sensitive elemental modal strain energy to locate damaged elememtssuccessfully.At last, damage extent is trulyevaluated with five mode shape at most.