Lattice sandwich plate damage identification method based on structure time domain response

Abstract

The invention provides a lattice sandwich panel damage identification method based on structure time domain response, which comprises the following steps: firstly, extracting the displacement of eachnode of a lattice sandwich panel through numerical simulation or experiment to obtain the power of each node of the lattice sandwich panel; carrying out normalization processing on the power; proposing a damage index to determine the existence of the damage according to the power difference between the intact identification and the damaged lattice sandwich plate; selecting a used two-dimensional wavelet type, determining a used decomposition layer number and a wavelet coefficient, and performing two-dimensional wavelet transform on the damage index to obtain a wavelet coefficient and obtain anew damage index; standardizing the damage indexes, converting data into dimensionless index evaluation values, that is, all the index values are located on the same number level; and then obtaining specific damage position information. The method can be directly applied to a structure with nonlinearity, high damping or high modal density through a time domain method, high-order data difficult toobtain do not need to be extracted in an experiment, initial data identification damage can be directly processed, and calculation errors are reduced.

Description

technical field [0001] The invention relates to the field of lattice sandwich panels, in particular to a damage identification method that can effectively eliminate the influence of the singularity of connection points on damage identification, and only use the time domain response of the structure to confirm the location and quantity of damage in the lattice sandwich panel . Background technique [0002] Lattice sandwich panels have many excellent properties, such as high stiffness, high strength, good impact resistance, good heat insulation and sound insulation. It is precisely because of its many excellent properties that lattice sandwich panels are widely used in aerospace, civil engineering, transportation and other fields. However, due to the complex manufacturing process and long-term use, it is inevitable to produce various defects, such as peeling between the face plate and the sandwich layer, and damage to the face plate and the core layer, which may reduce the lo...

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Problems solved by technology

[0004] (1) The dot-matrix sandwich panel is more complex in form, so the effect of the traditional non-destructive testing method is not so obvious;

[0005] (2) The stiffness and mass of the structure are increased to make the dynamic properties of the structure more complex, which affects the damage identification based on the vibration mode to a certain extent;

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