Underwater shell modal test method considering internal flow field and pressure influence thereof

Abstract

The invention provides an underwater shell modal test method considering an internal flow field and pressure influence thereof. The method comprises the steps that a strain gauge ispasted on the outer circumference of a test body, and a digital acquisition instrument is connected through a cable; a test body is suspended in a pressure box by using a spring pull rod, and a non-contact excitation device is mounted at the bottom of the pressure box; high-pressure water is injected after gas in the pressure box is discharged; the excitation device is started to apply vibration with a preset frequency to the test body, and the data acquisition instrument acquires strain data of the strain gauges and excitation force data of the excitation device and then sends the strain data and the excitation force data to the analysis system so as to output stress and strain results of the test body. The device simulates the flow field and the pressure action of the test body in a real environment, and carries out the modal test on the test body on the basis, the test simulation of the circumferential modal of the test body can be rapidly and efficiently realized through each step, the process is easy to operate, the data is more accurate and reliable, the test period is short, and the economical efficiency is strong.

Description

technical field [0001] The invention relates to the field of vibration testing of underwater structures, in particular to a method for carrying out modal tests on underwater shells in a non-contact excitation mode while considering the influence of the internal flow field and its pressure. Background technique [0002] The hollow shell structure is a typical engineering component. Compared with most solid structures, the shell structure has a lighter weight under the premise of ensuring a certain strength and stiffness, so it is widely used in underwater vehicles, platform pontoons and Design and construction of marine engineering structures such as underwater pipelines. [0003] In actual engineering, the influence of external fluid on the vibration of the underwater shell cannot be ignored. Under the coupling effect of water pressure and flow field medium, when the underwater shell is excited to vibrate, it will cause the vibration of the surrounding fluid medium, while T...

AI Technical Summary

Problems solved by technology

[0006]1. Existing modal test devices for underwater shells mainly consider the influence of the external flow field, while few consider the influence of the internal and external flow fields at the same time, involving internal pressure The experiment of the study is even rarer;

[0007]2. Existing modal tests mostly use displacement sensors or acceleration sensors to obtain strain data. Vibration modes of external f

Images