Damage Identification Of Tensegrity Structures Based On Flexibility Decomposition

As a new type of spatial grid structure,the tensegrity structures has the unique shape and approximatly neglected weight.Cables or chains are used as tension members to satisfy the advantages of continuous arrangement?high material strength and light weight of tension members,and steel or other composite materials are used as compression members to satisfy the the advantages of incontinuous arrangement?high material properties of compression members,and each node in the tensegrity structure only contacts with the compression member.Local damage of materials and aging of structural components will inevitably occur in the service cycle of buildings,which will have negative effects on the safety,reliability and long-term performance of the service of structures.Therefore,in order to avoid the appearance and occurrence of major structural accidents and reduce unnecessary personnel and property losses,it is of great significance to carry out damage analysis of tensegrity structures based on flexibility decomposition,and it meets the requirements of green building production.Via Matlab platform the finite element numerical model of the tensegrity structure is developed.The stiffness contribution of each element of the structure is considered in an effective cumulative way.The total stiffness of the tensegrity structure is composed of geometric stiffness and linear stiffness.Then the stiffness connectivity matrix of the tensegrity structure is derived.The stiffness connectivity matrix,as the inherent characteristic matrix of tensegrity structure,will not change whether the damage occurs or not.Then the dynamic equations of the damaged and intact tensegrity structures are calculated,and the modal shapes and frequencies of the damaged and intact tensegrity structures are obtained by solving the structural characteristic equations and supplementarily processing homogeneous,meanwhile the flexibility change matrix of the tensegrity structures are obtained.Finally,the damage flexibility information matrix of the damaged tensegrity structure is obtained by the relationship between the flexibility change matrix and the flexibility connectivity matrix.The elements in the damage flexibility information matrix are the damage information of the damaged tensegrity structure,so as to know the damage location of the damaged tensegrity structure and the damage degree of the damaged tensegrity structure.In order to verify the reliability of flexibility decomposition and taking into account the spatial dimension of tensegrity structures,the single member damage analysis and noise error analysis are carried out for the tensegrity structure plane beam.Two adjacent members damage analysis and two non-adjacent members damage analysis are carried out for the tensegrity quadruplex structure.The multirepeated responses of three members of the tensegrity structure space beam are studied in turn.The numerical results confirm the reliability of the damage identification method based on flexibility decomposition.The most prominent point of damage research of tensegrity structure based on flexibility decomposition method is to derive the stiffness connectivity matrix of tensegrity structure,and it does not need iterative calculation and has fine precision.Based on the flexibility decomposition method can accurately grasp the damage status of the tensegrity structure regardless of the damage severity of the tensegrity structure.It shows the superiority of the based on flexibility decomposition method,improves the theoretical basis of the tensegrity structure,and has certain engineering application values.