Statistical Damage Identification Of Space Truss Structures Through Experiment Research

Civil engineering construction not only requires a lot of investments in the country,and the consequences are often lasted for hundreds of years,it will have a significant impact on the present and future of the country,especially for the truss structure.Because of the initial defects of component materials and their subjections by the loads and the effects in the environment,after a long time of use or suffering from some natural disasters,they usually have a certain degree of injury.Studies found that at present,our country has a large number of building structures working in the state of sick,especially for the reinforced concrete structures which in the harsh environment,they are more likely to get serious injury.Some components can't meet the seismic design standards,their safety performance is congenitally deficient,these security risks if not promptly removed will cause greater accidents.Therefore,it will be an important field in the development of civil engineering to regularly implement damage diagnosis and health monitoring,to find the damage of components in time and evaluate the damage structure.Basing on the existing model of the space truss structure,research and analysis are conducted through theoretical analysis and experimental methods for structural damage identification,in this article the main contents are:1.Introduce the calculation method of the space truss displacement method and shows the programming ideas of space truss model in detail.2.A damage diagnosis method of stochastic structure which takes the static measurement data into account is introduced,and the model error and measurement noise error of space truss structure under external forces are studies with mathematical statistics method.Take advantage of stochastic finite element method and static condensation principle to calculate the damage index and the damage probability of each element of the space truss.3.Focusing on the means of experiment,the space truss simple-supported structure damage identification is studied.Respectively use the damage round bar in the 4,6,14 unit of the truss,and measure vertical displacements of its six nodes,each test we take 6 groups of experimental data.Having analyzed the data collected in the test,we take the damage identification algorithm proposed by the research group and get the mean value of damage index and damage probability index diagrams,through experiment analysis we find that the recognition results consistent with actual damage,and the space truss statistical damage identification method is verified.4.In order to improve the accuracy and stability of the damage identification effects,we give a new improved method for random structures.This method regards the small probability of damaged bars as perfect units,and then readjusts the mean value of damage index and standard deviation,put them back to the control equation to get the damage identification.The recognition results show that the improved method can diagnose the damage of the component effectively,as well as reducing the possibility of misjudgment,and the recognition effect is well improved.