Modal tests and properties analysis on truss structure of large scale carbon fiber

Based on stochastic subspace system identification method, the modal properties of the truss structure of large scale, light weight, high strength, and force bearing type carbon fiber composites were investigated by ambient excitation. On basis of the characteristics of the truss structure itself, three fundamental assumptions were forwarded. In conjunction with the constraint conditions of the truss structure in practical applications, a modal test scheme for the truss of large scale carbon fiber composites was designed. Through detailed analysis of the test results, the characteristics of frequency, damp, and vibration mode were summarized. By hammer impacts test and finite element method, the test results were comparatively analyzed. It is proved that the three fundamental assumptions are reasonable, the test scheme is effective, the analytical results of the test are reliable. The research results are of essential meaning to the design of aerostat structures and their health monitoring.