SU1735400A1 - Method of vibrostabilizing metal structures - Google Patents

Abstract

The invention relates to vibroacoustic technologies. The essence of the invention is a key & in that they vibrately process a free structure in a forced oscillation mode, simulating the operating modes of loaded structures, and perform it in the following sequence. Static processing is performed and a probabilistic acoustic passport of the loaded structure is compiled, forced oscillations are performed in a free design at discrete frequencies of the modes of the loaded structure at each frequency of the spectrum for 15-30 min with sequential use of each row of vibrators as a master and synchronization others by changing the excitation phase to obtain the maximum amplitude of the forced oscillations. 1 silt

Description

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This invention relates to vibroacoustic technologies.

Loaded real basic shell structures (with installed working mechanisms) in the initial period of operation retain technological hereditary features that can be described, in particular, by size, sign, distribution of residual stresses. During operation, under the influence of forced oscillations initiated by working mechanisms, the redistribution and relaxation of residual stresses and, as a result of these changes, the acoustic characteristics of the structure shift. This is how prerequisites arise for the occurrence of unregulated (harmful) resonances at discrete, unaccounted for at the design stage, design frequencies that reduce the operational reliability of the product as a whole.

A resonant method of vibro-processing of structures is known in order to stabilize its geometrical dimensions, which means that the structure is processed at one of the resonant peaks in order to redistribute the residual welding stresses in the sequence: scanning the frequency range, recording the frequency response, vibrating at the selected frequencies of the resonant peaks, control of change of frequency of resonant

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peaks, relaxation, determination of the period of stabilization of the frequency of resonant peaks.

The disadvantage of this method is that with large dimensions of the product, it is necessary to reinstall the vibrator along the length and repeat the vibration treatment, since the effective redistribution of stresses is observed at a distance of no more than 2 m from the source of oscillations. In addition, the method is based on the creation of single-mode oscillations at the natural frequencies of a loose structure and does not ensure the reliability of acoustic stabilization at all possible modes of oscillations of complex structures.

The purpose of the invention is to increase the operational reliability of metal structures loaded with working mechanisms, based on the proactive stabilization of the stress-strain state at the stage of manufacture of the structure.

The goal is achieved by the fact that the vibration processing of free, unloaded structures at the stage of their manufacture is carried out in the mode of forced oscillations at the resonant frequency of the loaded structure and is carried out in the following order: statistical processing is performed and a probabilistic acoustic passport of the loaded structure is effected; to a free design by forced oscillations at discrete frequencies of operating modes of the loaded structure by means of multipoint synchronous excitation waiting at each frequency of the spectrum of a loaded structure for 15–30 min with successive use of each vibrator as a driver and synchronizing all the others in the oscillation mode set by it by changing the excitation phase to the maximum of the amplitude of the forced oscillations in the metal structure.

Thus, in the proposed solution, a multipoint synchronous vibration excitation of the structure is used at the stage of production of the loaded structure in operating modes of oscillations in the mode of forced oscillations before its acoustic stabilization to increase the operational reliability on this basis.

The drawing shows a device for implementing the proposed method.

The device contains a controlled rectifier 1, a filter 2, inverters 3-6 with adjustable frequency and phase, synchronous motors 7-10 with nodes 11 and 12 of the unbalance, providing the ability to control the amplitude and phase of oscillations along the process, the switch 13 channels , measuring complex 14, rectifier control system 15, which provides the law of frequency control, inverter control blocks 16-19 — matching devices, voltage phase control, control computer 20, sensors 21 and 22 with preamplifiers that measure amplitude, frequency, and oscillation phases.

The device works as follows.

From inverters 3 and 4, synchronous motors 7-11-8 of the vibrator are started at the discrete frequency of the spectrum of the operating mode of oscillation of the structure. At the same time, the law of frequency regulation on the inverter is ensured by a proportional change in the output voltage on the controlled rectifier 1. Then, using switch 13, the amplitude, frequency and phase of the oscillation of the structure are measured through the appropriate information channel with sensors 21 and 22 and synchronize the vibrator 9-12 -10 on the oscillation mode of the first vibrator 7-11-8. The amplitude and phase of oscillation of the master vibrator is set according to the acoustic passport from the control computer 20. According to the signals from sensors 21 and 22, and commands from computer 20 to matching devices 16-19, the voltage phase of each motor is adjusted and, therefore, the spatial position of the rotors and the unbalances fixed on their shafts, respectively, to the set values of the amplitude and phase of the oscillations of the structure. The described operations are performed sequentially with each vibrator on all spectrum frequencies.

The use of the invention will improve the reliability of stabilization of the stress-strain state of the basic hull structures, their acoustic and operational characteristics.

Claims (1)

The method of vibration stabilization of metal structures mainly by vibrators, including determination of the frequency response and vibration treatment of the metal structure at specified frequencies, characterized in that, in order to improve the operational reliability of the loaded metal structure, the resonance frequencies of the loaded metal are determined. metal constructions and act on the unloaded metal constructions by forced oscillations of the frequencies determined above for 15-30 minutes with the consecutive use of each row of vibro360 V 50 hectares. rators as a master and synchronization of the rest by changing the phase of the excitation until the maximum amplitude of forced oscillations in the metal structure is obtained.