The Study Of Long-Xi Based On Modal Analysis And Modal Updating Technology

Finite element is the method using mathematical approximation to simulate the real physical systems with advantages of integrity, accuracy and ease of procedures etc. It has currently been used in the field of structural analysis widely. For complex structures, errors often exist, testing is costly, and development cycle is long. And finite element analysis of the natural frequency, damping, vibration mode and testing results are not correct. Model updating technology can solve the problem. Model correction technique solves the problem between the relevant test results and structural calculations with effective means of correction parameters, so that the finite element model reflects the true state of the structure as much as possible.In this paper, Long-xi and Long-xi phenomenon are discussed, and a Long-xi modal characteristics amendment of the finite element method is researched for the comprehensive use. This paper also tests Long-xi modal with the application of laser sensors and other equipment, modify the mass distribution of the object structure, size parameters, and the material modulus because of material uncertainty. Mainly for the following several aspects:Long-xi modal test to determine the order of the dragon to wash the first six modal parameters;Long-xi parameterized finite element model is built;Sensitivity analysis determines the model correction for determination of design parameters;Structural optimization uses the model updating to solve problems.The impact of additional parameters is excluded in Long-xi modal testing using non-contact laser sensor. The Long-xi finite element analysis, will model in CAD software, and analyze CED software. Finally, the use of model correction technology and optimization of the sensitivity analysis method can not only study the phenomenon of Long-xi, but also can be used for main range of versatility.