Fracture Damage Monitoring And Identification Of Space Truss Structure

Truss structure is a common form of space structure.Based on the advanced space platform of our country and the purpose of local damage monitoring of truss structure,based on the theory of space truss structure and quantitative assessment theory,a series of experimental studies are carried out.The space truss structure applied to the satellite damages identifying,and the health performance of the truss structure is preliminarily obtained.Based on the research of data mining,two quantitative evaluation methods based on the similarity analysis and the principal component analysis are proposed.The results provide the basis for the quickly determination of the damage on the truss structure in the future.In this paper,the truss structure of the satellite is the reference object,designed and carried out the modal test,with the finite element model of the modal simulation analysis and the specific modal test analysis to determine the structure of the dynamic characteristics;and then designed and launched a stimulus vibration tests were performed to simulate the perfect condition and typical damage condition of the satellite truss structure.The similarity analysis method and the principal component analysis method were used to deal with the frequency response data before and after the damage.The results show that the difference of the pre-dithering caused by the local truss damage is mainly the response amplitude value change,and with the resonance peak drift and the number of changes.Smaller than the cut-off frequency fc before and after the frequency band damage frequency response curve is higher,more than fc frequency band before and after the damage frequency response curve there is a significant difference.For the first 10 principal components of information response curves before and after damage,the comprehensive index of multi principal element ratio and principle element method-root mean square ratio can accurately identify the damage point near the area,locate the space truss structure's typical damage;square prediction error ratio can estimate the degree of the space truss structures damage.Square prediction error ratio can identify the degree of damage to the space truss structure.