Simulation And Experiment Study On Damage Degree Identification Of Space Grid Structure

Space grid structure at home and abroad is one of the most common form of large span space structure,network frame of the overall collapse due to bar damage cases,caused the scholars to the attention of the space grid structure health detection.Predecessors' study of space truss structure health detection method is through the static characteristics and dynamic characteristics method,computational intelligence,which can identify the damage degree of space truss structure have their advantages and disadvantages of this method.If can apply a more ideal method of accurate control of space truss structure damage degree can effectively avoid because of the collapse of space truss structure threat to people's life and property safety.By displacement,the static characteristics,dynamic characteristics method is a combination of axial force,the time history method,the application of axial force change law of space truss structure damage identification,to achieve the effect of complement each other.To overcome the dynamic method is not applicable to complicated structure and the working condition of symmetric structure damage identification,as well as solved the problem of the method of static characteristic recognition effect is bad,but also improves the accuracy of damage identification.Location-based damage under the premise of bar,through model test and numerical simulation method,time history method is applied to damage identification study of four pyramid spatial grid member.In this paper,the displacement of the two ends of the bar is obtained,and the curve of the time course is simulated by Matlab.Results show that under different damage conditions,damage on both ends of the bar node displacement time history curve can approximate to synthesis of straight line,through to the slope of the straight line and bar damage degree analysis of upper chord respectively on both ends of the pieces,CHS,lower chord node displacement time history of straight line slope of K value,the relation between the damage degree and the bar.Based on positioning damage under the premise of bar,by means of model test and numerical simulation,the application method of axial force change damage identification study of four pyramid spatial grid member.The relationship between the shaft force change and the extent of damage degree of the shaft is obtained by means of the upper chord of the frame structure,the abdominal rod and the lower chord.The effect of frequency method on measuring the shaft force of the frame is also verified.On the above two methods in the practical engineering of rack bar damage recognition effect has carried on the simulation study,the results show that using the time history method torack bar damage recognition effect is accurate.The method of axial force change is not good for the slight damage recognition of the frame structure,but it is more accurate when the structure of the lattice is more serious.The method is more accurate to identify the damage to the frame of the frame when the network frame has more than 18% damage.At the same time,application of the two methods used to identify the damage on the same network frame structure,can effectively overcome the dynamic method,the disadvantages of static characteristic method,increase the rate of damage identification of fault tolerance.Through the study of these two methods,it is helpful to identify the application of network frame structure injury to the application of practical engineering.research of the above two methods for space truss structure damage identification in the practical engineering application has played a reference role.