SU1434304A1 - Method and device for determining damping coefficient - Google Patents

Abstract

The invention relates to a measurement technique and can be used to determine the damping properties of objects. The purpose of the invention is to improve the measurement accuracy, achieved by simplifying the formula for calculating the damping coefficient. In carrying out the operations of the method, the frequencies of the maximum and minimum of the real part of the frequency response obtained by developing the excitation frequency of the vibrator are measured sequentially, and then their half-difference is calculated. A sufficient frequency separation with this and a simple calculation formula makes it possible to increase the measurement accuracy by reducing the computational errors. 2 sec. f-ly, 1 ill. C /) C

Description

 The invention relates to a measurement technique and can be used to determine the damping properties of mechanical objects, t The purpose of the invention is to increase the accuracy of the measurement due to the fact that the proposed set of operations is characterized by a simple formula for calculating the damping coefficient Ii with sufficient separation of measured frequencies .

The drawing shows a block diagram of an apparatus for implementing a method for determining a damping coefficient.

The device contains a series-connected generator 1, an adjustable amplifier 2 and a vibrator 3, on which I accommodates the first vibratory transducer 20 I, the distributor 4, the second vibrating transform; The detector 5, the phase detector 6, the first i 7 and the second 8 accompanying filters, connected by signal inputs to the vibration transducers A and 5, and the control filters 25 to the control output of the generator 1, the maximum separation unit 9, the block 10 of the minimum, the first 11 and second 12 keys, the information inputs of which are connected to the output 30 of the code of the frequency of the generator 1, and the control inputs to the outputs of the corresponding. but maximum and minimum allocation units, an analog multiplier 13, the first input of which is connected to you- from the second accompanying filter 8, and the output to the inputs of blocks 9 and 10, functional converter 14, input KoTof) oro connected to the output of phase detector 6 and the output to the rum input of the analog multiplier, the computing unit 15, the inputs of which are connected to the outputs of the keys 11 and 12, and the display unit 16 connected to the output of the computing unit. ds

The method for determining the damping coefficient is as follows.

Generator 1 sweeps the frequency of an electrical signal in a given frequency range. Amplified by amplifier 2, this signal is fed to the vibrator 3, the excitation of the o6beKta 17 installed on it. At the same time, the vibrating transducer 4 installed on the vibrator and the vibrating transducer 5 located on the object 17 produce the corresponding signals:

50

t Yu

15

20 25 30. with about with

0

The signal from the vibration converter 4 through the first accompanying filter 7 controls the amplifier 2, stabilizing a given level of oscillations. The response signal of the object 17, taken from the vibrator 5, is supplied through the second accompanying filter 8, the first input of the analog multiplier 13. From the single control outputs of the accompanying filters 7 and 8, the signals arrive at the inputs of the phase detector 6, which, through the functional converter 14, controls the function cos, the signal arrives at the second input of the analog multiplier 13. At the time of passing through the maximum of the signal from the output of multiplier 13, which corresponds to the maximum of the real component of the frequency x The characteristics of the system, the allocation unit 9 generates a pulse that opens the key 11, and the frequency code from the output of the generator 1 is fed to the first input of the computing unit 15.

The frequency sweep process continues, and when the signal from the output of the multiplier 13 reaches the minimum, which corresponds to the minimum of the actual frequency response of the system, the minimum level block 10 is triggered by sending a command to the control input of the second key 12, resulting in the second input of the computing unit 15 from the output of the generator 1 receives the code of the corresponding frequency.

Computing unit 15 calculates the value of the damping coefficient by the formula

. (Wa - U,),

where & is the damping coefficient

having a frequency dimension representing the ratio of attenuation to oscillation period;

CO, is the frequency of the maximum of the real component of the frequency response; BO is the frequency of the minimum.

The result of the calculation goes to block 16, where it is displayed.

Claims (2)

1. A method for determining the damping coefficient of an object, which includes the excitation of forced oscillations and the frequency range of the near-resonance region, characterized in that, in order to increase accuracy, a frequency characteristic of the system is obtained at a constant level of excitation in the frequency range, at which the actual component frequency response has a maximum, and the frequency at which the actual component of the frequency response has a minimum, and the damping coefficient is determined from Ole eight one  (g-sO), CO, is the frequency of the maximum of the characteristic; C0 (| - frequency of the minimum characteristics. 2. A device for determining the damping coefficient of an object, containing a series-connected JQ generator, an adjustable amplifier and a vibrator, the first vibration transducer placed on the vibrator, the second vibration transducer installed five 0 five Q, the first and second accompanying filters on the object under study, connected by a signal input to the corresponding vibration transducer, control input - to the generator control output, and the output of the first filter connected to the control input of the amplifier, maximum allocation unit, first and second keys, information inputs of which are connected to the output of the frequency generator of the generator, and the control input of the first key is connected to the output of the maximum allocation unit, a computing unit whose inputs are connected to the outputs of the keys and an indication unit connected at the output of the computing unit, characterized in that, in order to increase accuracy, it is equipped with a phase detector, the outputs of which are connected to the control outputs of the accompanying filters, a functional converter whose input is connected to the output of the phase detector, analogue by a terminal whose outputs are connected to the outputs of the functional converter and the second accompanying filter, and the output to the INPUT of the maximum allocation unit, and a minimum separation unit whose output is connected to the multiplier output, and the output to the control input of the second key ..