Vibration modeling and analyzing method of crack impeller structure of centrifugal compressor

Abstract

The invention discloses a vibration modeling and analyzing method of a crack impeller structure of a centrifugal compressor. The vibration modeling and analyzing method comprises the steps of firstly, providing a modeling method of a centrifugal impeller, obtaining a whole model by rotating and converting a finite element model of a section of the impeller, reducing the DOF (Degree of Freedom) of a system by adopting a hybrid interface modal synthesis method, and simulating a breath effect of a crack by defining a contact mode on a crack interface; secondly, providing a method for solving large-scale symmetrical sparse matrix-inverse matrix, and thus obviously reducing the memory space needed by calculation; finally, providing a method for carrying out statistical analysis on resonant frequency of the crack impeller structure, considering dissonant factors such as manufacturing error and state degradation which exist in an actual impeller, and obtaining statistical regularity of structure resonant frequency under a random dissonant mode. According to the vibration modeling and analyzing method disclosed by the invention, the calculating accuracy is ensured, obvious improvement effect of calculating efficiency is realized at the same time, and a high-efficiency analyzing method is provided for optimal design of the impeller and quantitative diagnosis of the crack.

Description

technical field [0001] The invention belongs to the field of structural dynamics modeling, and in particular relates to a vibration modeling and analysis method for a cracked impeller structure of a centrifugal compressor. Background technique [0002] Centrifugal compressor is an important equipment widely used in petrochemical, steel, electric power and other industrial fields. The impeller is the heart of the centrifugal compressor rotor and one of the most prone to failure. Due to the influence of complex alternating stresses acting on the impeller, the structure is prone to fatigue crack initiation at weak positions. When the crack expands to a certain depth, a blade breakage accident will occur. For a rotor operating at high speed, the broken blade will not only damage the unit, but also threaten the safety of personnel on site. [0003] The centrifugal compressor rotor is a complex system and operates in a complex airflow excitation environment. In order to develop...

AI Technical Summary

Problems solved by technology

However, since the statistical analysis often contains thousands or even tens of thousands of random patterns, the time required for the analysis is unacceptable if the finite element model of the structure is used directly

In addition, statistical analysis also requires a high level of computing hardware, which cannot be met by ordinary workstations.

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