Damage Assessment Method Of Structure With Fiber Element And Program Implementation

In order to realize the seismic performance-based design of reinforced concrete structures,it is necessary to quantitatively describe the damage degree of structures under earthquake action.Fiber element can consider both efficiency and accuracy in nonlinear analysis of structures and provide damage information at material level.The damage information is complete and can reveal the nature of structural performance evolution.The component damage index and structural damage index confirmed by the material damage of fibers are suitable methods for structural damage assessment.To determine the damage information processing method of fiber element,a fiber beam-column element suitable for structural damage assessment is developed in this paper.The reasonable expression of cross-scale damage information of materials,components and structures is concentrated on.And a quantitative analysis method and visualization program of structural damage degree with fiber material damage information is formed.The specific works are as follow:The flexibility-based fiber element with the modified compression field theory(MCFT).With the biaxial constitutive model of concrete according to MCFT and the constitutive model of steel bar considering compression buckling effect combined,the fiber element of flexibility method can simulate the coupling effect of bending,shearing and compression,and then simulate various damage modes of beam-column members.The problem of displacement control and negative stiffness is solved by using the iterative method based on total quantity and deformation separation method is proposed to make the method of calculation further.All these works lead to a calculation program with good convergence performance.Several typical examples are used to verify the correctness of the program.These achievements provide a good platform for accurate analysis of material damage information.Damage description of beam-column components with fiber element.The damage of structural components comes from the deterioration of material properties.The damage description of concrete is introduced into the process of structural analysis,and then a damage evaluation method based on material damage is established.The damage and failure modes of beam and column members are studied,and the classification influence parameters and quantitative classification criteria are given for some typical damage and failure modes,which leads to a method for judging the failure form of a component based on its external force characteristics and material characteristics.The material damage index,section damage index and component damage index are given.After the nonlinear analysis and damage analysis of several beam column members with different damage modes,a unified and quantitative standard for damage degree of beam and column members is proposed.Structural damage description and visualization method.Based on the threedimensional modified compression field theory and flexibility-based element theory,a space structure calculation program is established suitable for simulating various spatial stress states.The reliability of the program results is verified by several examples.Based on the quantitative evaluation method of component damage,the damage information transmission method from component damage to structural damage is studied,and the damage analysis process and method of overall structure is established.With the help of VTK and Qt,the structural analysis and damage information visualization module is developed to express the structural damage analysis data efficiently and vividly.