Non-traditional damping system damping matrix identifying method

Abstract

The invention provides a non-traditional damping system damping matrix identifying method which is based on unit matrix decomposition and can handle with three-dimensional space problem, aiming to solve the status quo that only low-order mode information is available in the traditional mode testing technology under environment excitation and overcome the problem that the relative high-order mode information is required at certain extent by the traditional damping matrix identifying method. The required practically tested vibration type can be the multiplex vibration type, the quality normalization is not required, and the method can be well suitable for the status quo that the damping matrix only can be accurately measured by the finite low-order mode; after being combined with the mode parameter identifying technology based on output response, the method can identify the non-traditional damping system damping matrix of the ocean platform under the environment excitation.

Description

technical field [0001] The invention relates to a non-traditional damping matrix recognition method for marine engineering structures, in particular to a non-traditional damping matrix recognition method using only a few low-order measured complex modes. Background technique [0002] Large-scale engineering structures such as offshore platforms will exhibit a certain degree of energy dissipation during their service. As long as the energy dissipation of the structure is involved, damping plays a vital role in the response process of the structure. Traditionally, this energy dissipation has been attributed to the inherent damping of the structure, and the internal friction of materials, connections, and nonstructural components is an important factor affecting structural damping. For the convenience of mathematical processing, it is usually assumed that the damping matrix is ​​a linear combination of the mass matrix and the stiffness matrix, that is, the commonly used "propor...

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Problems solved by technology

As Lancaster said, the disadvantage of this method is that the mode shape needs to be normalized, but the existing test methods cannot obtain the normalized mode shape, which limits the further application of the method

[0013] On the one hand, the above method requires higher-order measured mode shapes, and on the other hand, it also puts forward higher requirements for the normalization of measured mode shapes and the selection of variable matrices, and these conditions cannot be fully provided in practical engineering applications. , which limits further engineering applications

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