METHOD FOR ANALYZING COUPLED VIBRATION OF FLUID AND STRUCTURE

摘要

PURPOSE:To apply to a complex structure by noting only a necessary vibration mode of the structure and calculating an added mass of fluid corresponding to it. CONSTITUTION:The number of natural vibrations and the intrinsic modes of fluid and a structure at the time of coupled vibration are obtained with an added mass of fluid taken into consideration. At this time the number of natural vibrations and the intrinsic modes of the structure at the time of non-coupled vibration are used to transform the equation of the structure to a mode coordinate system, wherein the matrix is reduced and an added mass of the fluid is calculated corresponding to the respective modes. This is added to each mode mass of the structure, eigenvalue analysis is performed in the mode coordinate system, and the number of natural vibrations and the intrinsic modes are calculated. Using these as the new number of natural vibrations and intrinsic modes of the structure, a corresponding added mass is calculated. This is repeated until for example their changes are at a specified value or lower and converged, to obtain the number of natural vibrations and the intrinsic modes at the time of coupled vibration. Thus the matrix is reduced and the method can be applied to a complex structure.