SU1462361A1 - Device for collecting and processing the results of impact testing - Google Patents

Abstract

The invention relates to a measurement technique and is intended for use in the processing of low-frequency results of shock tests and short-term dynamic loads. The purpose of the invention is to improve the accuracy of processing. When conducting shock tests with the object 12 tests on the block P reproduce

Description

/

fc1 one

The impact of the shock load, operating according to the principle of release of a winded-Hiiix springs on a rec-onboard astatine of object 12, causes damping oscillations. These damped oscillations cause changes in the electrical signals on the sensors 9 installed on the object 12. These signals are transmitted through the matching units 8 to the block ..7 of the buffer memory. -Before testing, block 7 records the calibration signal from sensor 9 and the reference signal from the generator 10 reference signals. After the end of the test, the recording is transmitted to the control and spectral processing unit 3, where the information is processed according to the program. At the operator's command, the initial data is entered into the memory of Block 3: the base address of the data (BAA); sin and cos arrays; The frequency of 200 bytes / s and the amplitude A of the calibration signal. The invention relates to measurement technology and is intended for use in processing low-frequency results of shock tests and short-time dynamic loads.

The purpose of the invention is to improve the accuracy of processing.

FIG. 1 shows a block diagram of the device; FIG. 2 shows an expanded impact processing algorithm; in fig. 3 - algorithm for calibrating the reception frequency and amAlitude; in fig. 4 - frequency determination algorithm; FIG. 5 - amplitude calibration algorithm; on

FIG. 6 - algorithm for receiving information; Fig. 7 shows an algorithm for determining the spectral density; in fig. 8 and 9 are examples of processing results.

The device (. 1) contains a standard instrument interface 1, blocks of 2 interface modules, block 3 of control and spectral processing, made on a microcomputer, an analog-digital-to-digital converter (ADC) 4, switch .5, plotter 6, block 7 of the buffer memory ti, complete PA magnetograph, matching blocks 8,

Nala The operator then plays the recording in block 3, connects one of the studied channels of block 7 to the input of ADC 4, and calibrates the program for receiving information with a frequency Hz and amplitude A, calculating the multiplier K and translating the code in block 3 into a real physical quantity (in this case overload). Next, the kick process processing program begins. At the command of the operator, the recording of the impact process is played. Block 3 determines the beginning of the shock process and takes it into a pre-allocated array of memory in the form of equidistinal ordinates of the realization of the impact process being studied. At the command of the operator, this implementation is decomposed into c. Fourier series and determine the spectral density estimate (energy spectrum) of the impact process under investigation. 9 il.

sensors 9, a reference signal generator 10, and a shock load reproducing unit 11.

Unit 11 operates on the principle of releasing the sprung springs at the resonant frequency of the test object 12.

The device works as follows (Fig. 2),

When conducting shock tests with an object in block 12, damped oscillations occur. These damped oscillations cause changes in electrical signals on sensors 9 installed on object 12, which through matching blocks 8 enter block 7. Before testing, block 7 records the calibration signal from sensors 9 and the reference signal from generator 10. After the tests end, the record from block 7 is rewritten into block 3, where the information is processed according to the program of Fig. 2).

At the operator's command, the initial data is entered into the block memory: base data address (OVER); masses sin and cos, byte / s frequency and calibration signal amplitude AK.

314

 Then the operator switches on the playback of the recording of block 3, connects one of the studied channels of block 7 to the input of А1ДП 4 and produces; calibration of the program for receiving information (Fig. 6) with a frequency of Hz and amplitude A, calculated the multiplier K ,, and translating the code in block 3 into a real physical quantity (in this case, an overload).

Next, the kick process processing program begins. At the command of the operator, the recording of the process is played back, and it is received into the previously allocated memory array in the form of equidistant ordinates of the realization of the impact process under investigation. ; At the command of the operator, this implementation undergoes a discrete Fourier transform and calculates the spectral power density of the process under study.

9 .. N

X. Cos

21K; 7) h.

Ikjf n j

After the processing is completed, unit 3 determines the scale and displays the graphs of the process n (t) and spectral under consideration by the operator’s commands; density s (t) on plotter 6

The program for calibrating the frequency of reception .. Hz and amplitudes (Fig. 3) is intended for metrological assurance of the treatment of impact processes. It allows you to set the required reception frequency (byte / s) of information and determine the calibration factor K, to convert the code in block 3 to a real physical quantity. This is done as follows.

Having set the initial time of one measurement .., T. (T, -fT, where T is the time of one measurement; T is the time of the operation of receiving the 1st count, cycles of block 3; Tj is the pause between measurements, set by software.

Block 3 receives a calibration signal in memory. Then, depending on the frequency of the calibration signal, block 3 according to the frequency determination program, (FIG. 4) determines the real number of measurements N and compare

vaet it with the given condition

 .. N (2)

If condition (2) is not met, an error is detected on one dimension ut

UOO NUJAO

200

and

(3)

Considering this error in the pause between measurements

VR10-f

(BUT)

15 20 block 3 again receives the calibration signal and analyzes it. This process continues until condition (2) is fulfilled. After condition (2) is fulfilled, unit 3 of the amplitude calibration program (r. 5) determines the calibration factor K in accordance with the formula

Ats2p

25

 IA;

(five)

.

thirty

where A is the calibration amplitude

signal;

Ay is the measured amplitude of the calibration signal. The program for receiving information allows receiving information from block 7 into the memory of block 3 with a predetermined frequency and a pre-allocated memory array. The frequency of reception is set by pause, determined by the program 35 calibration of the frequency of reception.

Determination of the spectral density S (f) (Fig. 7) is carried out with the help of a direct; Fourier transform

40,

45

and allows you to determine the spectral components

0

N o jTv, N

 / IIK., "R2LX .COS --- and bc 2-x

1h

Where

eleven

To N. 21K;

, sin --5

harmonic number; the number of measurements of the studied implementation,

from here

S (f J

2 9

-; 5 (ats + hc).

Claims (1)

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