Analysis Of Mid-frequency Vibration Response Of Supporting Cylinder Strengthening By Purlin

With the rapid development of society, people put forward higher and higher reliability and accuracy requirements for large complex combination structure dynamic design. Especially in the field of aerospace, aircraft are often subjected to harsh external environment, the vibration frequency range is very wide. There is a intermediate frequency area in this broad frequency domain, when combination structure vibrate in this domain, its dynamic characteristics is unsuitable be describe by low-frequency deterministic analysis methods, and also cannot be describe by high frequency statistical analysis method.This leads to a kind of new method for dynamic analysis: hybrid model method. According to the principle of modeling of coupling, the Hybrid model method is divided into a hybrid model method based on the modal coupling(hereinafter referred to as "M-hybrid model method") and the hybrid model method based on wave coupling(hereinafter referred to as "H-hybrid model method").This article is mainly aimed at two concrete structure of H-hybrid model to study the method of modeling, we must solve the dynamic stiffness matrix of each subsystem in the process of modeling. For coupling beam plate structure, we derive dynamic stiffness matrix of the beam by finite element method, and we derive dynamic stiffness matrix of the semi-infinite plate by the semi-analytical method. And they are applied to solve the Mid-frequency dynamic response of beam and plate coupling structure.About supporting cylinder strengthening by purlin, firstly,purlin bending vibration should be simplified to beam bending vibration, and then use directly the dynamic stiffness matrix of beam, the secondly dynamic stiffness matrix of the shell is also derived by the semi-analytical method. Then Mid-frequency vibration response of supporting cylinder strengthening by purlin are solve by the H-hybrid model method. Comparing the calculation results with software VA One respectively, the results verify the correctness about the dynamic stiffness matrix of these artifacts and H-hybrid model method.Finally, we calculate Mid-frequency vibration response of supporting cylinder strengthening in a certain period of Mid-frequency domain by using H-hybrid model method, the finite element method, and the statistical energy analysis method. Comparison of results show that calculation accuracy of H-hybrid model method is better than that of statistical energy analysis method, and the H-hybrid model method can effectively predict the vibration response of a combined system with frequency variation tendency, and the resonance near some frequency and resonance peak value. And the consuming calculation time of H-hybrid model method is far less than the finite element method, with the increase of frequency, the gap will become more and more significant.All of these embody the effectiveness and superiority about analysing Mid-frequency vibration response by H-hybrid model method.