Rigidity change device and method applicable to vortex-induced vibration testing system

Abstract

The invention discloses a rigidity change device and method applicable to a vortex-induced vibration testing system, and relates to the field of ocean dynamic and fluid and solid coupling testing. A physical spring is used for simulating system rigidity, defects in application of VCK are avoided, a linear overlapping principle is used, flexible changes of the spring on a hanging point of a sliding system is realized, and the work of system rigidity changes and work of vibrator pre-balance are made to be simpler and more convenient. Meanwhile, the aspects of selection of numbers and specializations and hanging of springs are more flexible, the testing cost is greatly reduced, the testing period is greatly shortened, and the testing efficiency is increased.

Description

technical field [0001] The invention relates to the field of marine dynamics and fluid-solid coupling tests, and relates to a physical device and a corresponding stiffness change method suitable for stiffness changes of a vortex-induced vibration test system. Background technique [0002] At a specific flow rate, the back side of the blunt body with a relatively large slenderness will generate alternating shedding vortices, and the pressure difference caused by the elasticity of the blunt body itself and the vortex shedding will make the blunt body follow the frequency (or multiplier) of vortex shedding. On the other hand, because the periodic motion of the blunt body changes the characteristics of the flow field, the vortex shedding behavior of the fluid changes, and this change causes the change of the motion of the structure again; finally, the fluid and the blunt body The body has reached a balance under mutual interference and action, and they are all in a stable state ...

AI Technical Summary

Problems solved by technology

However, there are two important technical problems in this method: (1) the transformation of the system stiffness, (2) the vibrator pre-balancing method after the stiffness transformation

However, there are many problems in VCK: (1) the use of sensors, main control system, servo motor and transmission will inevitably increase the test cost; (2) too many sensors will inevitably change the physical characteristics of the test model (mass, flow around (3) VCK is not intuitive, and the test process relies too much on the sensor and the main control system. Once a problem occurs, it is difficult to detect it. Even if the problem is found, it will take a lot of time to solve it, which will increase the test cycle.

However, the vertical arrangement of the vibrator is generally only suitable for the drag test of the static tank; for the vortex induced vibration test in the flowing tank, the difference in flow velocity between the top and bottom of the tank, the influence of the bottom boundary and the free liquid surface, and the influence of the two ends of the vibrator The asymmetry of the arrangement necessarily leads to considerable bias in the test results

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