Method for testing high-order frequency of large wind-power blades

Abstract

The invention discloses a method for testing high-order frequency of large wind-power blades. The method comprises the following steps of: firstly determining a reasonable test point arrangement scheme, exciting the blades by utilizing a high elastic energy-collecting hammer, testing a vibratory response of the blades by utilizing an acceleration sensor, collecting the blade frequency through a data collecting system, and finally recognizing modal parameters of the large wind-power blades through a rear-end server and determining the natural frequency of each order of the large wind-power blades. In the invention, the high-order frequency of the large wind-power blades is tested by using an improved non-weighing method, the characteristic of difficult excitation due to large aspect ratio, big mass, low natural frequency (first-order waving frequency is designed to be lower than 1Hz) of the large wind-power blades is overcome, and the high-order frequency of the large glass-steel wind-power blades more than 40m can be intuitively and effectively tested.

Description

technical field [0001] The invention relates to a method for testing the vibration mode of a large structural part, in particular to a method for testing the high-order frequency of a large wind power blade. It is mainly used for verification and monitoring of high-order frequency vibration modal characteristics of large wind turbine blades. Background technique [0002] With the large-scale development of the wind power industry, the length and flexibility of wind power blades are increasing, which makes the problem of blade instability more and more concerned. In order to prevent wind turbine blades from vibration instability and fatigue instability caused by resonance stress, prolong blade life, and avoid wind rotor instability and damage, it is necessary to find ways to reduce the resonance vibration stress of wind turbine blades during the design and preparation process, and to The design vibration modal characteristics of production wind turbine blades are verified an...

AI Technical Summary

Problems solved by technology

However, for large wind turbine blades, due to their structural characteristics of large aspect ratio, large mass, hollow shell structure, and low natural frequency (the design first-order wave frequency is lower than 1Hz), excitation and force measurement are difficult, so it is not suitable to use the force measurement

The non-measurement force method is a method that does not need to measure the excitation force during the test process. The method of environmental excitation is generally used, but the non-measurement force method of environmental excitation is greatly affected by external environmental factors, which is uncontrollable and difficult to measure, and its randomness is very high. Large, long sampling time, environmental wind load and noise interference often make it difficult to obtain accurate frequency test results without force measurement, especially for high-order frequencies of large wind turbine blades

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