SU1402834A1 - Arrangement for testing tubular specimens under conditions of two-component load - Google Patents

Abstract

This invention relates to apparatus for testing tubular specimens by internal pressure and axial force. The purpose of the invention is to improve accuracy by eliminating the effect of specimen deformation when measuring axial force. Sample 9 is installed in grips 2 and 3. The internal pressure in sample 9 is created using a multiplier 6 controlled from a pressure control unit. Axial force is created. by means of a hydraulic cylinder 4 controlled from an axial force adjustment unit. Compensation of the axial deformation of the sample from the internal pressure is accomplished by generating in the additional scale amplifier 15 a signal of the axial deformation of the sample from the internal pressure and summing this signal by the adder 16 with the signal of the current value of the axial force. 1 il.

Description

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The invention relates to test rexHHi e, namely to devices for testing tubular specimens by internal pressure and axial force.

The purpose of the invention is to improve accuracy by eliminating the effect of specimen deformation on the measurement of axial force,

The drawing shows a diagram of the proposed device.

The device contains a power frame

I and fixed 2 and movable 3 grips. The mechanism for creating an axial usi: LIA is made in the form of hydrocylin, center 4, on the stem 5 of which a movable gripper 3 is fixed. Mechanism of creation

: internal pressure is in the form of

; multiplier 6. The pressure gauge 7 is installed in the cavity 8 high

pressure multiplier 6 connected to the cavity of the tubular sample 9. The pressure gauge 7 is connected to the large-scale amplifier 10. The meter

I1 axial force is installed between; P1CoCom 5 and movable gripper 3 and connected to a large-scale amplifier 12. The device also contains a pressure control unit, executed as an adder 13, one input of which is intended to be connected to a master oscillator (not shown), and the second (inverse ) input-connected to a large-scale amplifier 10. First

the control unit 14 is connected to the output of the adder 13 and is designed to control the pressure in the equalizing cavity of the multiplier 6; to the output of the large-scale amplifier 10, an extra-large-scale large-scale amplifier 15 is connected to the output of which one of the inputs of the adder 16 is connected, the second input of which is connected to the output scale amplifier 12. The axial force control unit is designed as an adder 17, one input of which is assigned to connect a master oscillator (not shown) and the other (inverse) input is connected to the output of the adder 16. For When sample 9 is filled with liquid medium, the device is equipped with a pipeline 18 and a valve 19.

The device works in the following way.

The cavity of sample 9 is filled with a liquid medium. At the first input of the adder 13 receives the signal set

generator proportional to the internal pressure of the medium loading sample 9. The signal corresponding to the true current pressure value is supplied from the pressure meter 7 through the scale amplifier 10 to the second (inverse) input of the adder 13, at the output of which a pressure control signal is generated in the sample 9.

At the first input of the adder 17 receives a signal from the master oscillator, proportional to the value of the axial load. The second (inverse) input of the adder 17 receives the signal formed by the adder 16, and the ratio

SP

, (P). |. ..(R)

ABOUT)

de Cf, (F) - current value signal

axial force; q) (P) - signal / current value

pressure, SP channel sensitivity

pressure control; channel sensitivity

F

control of scale amplifier}

Sj, is the cross-sectional area of sample 9; The signal c (F) of the current value of the axial force measured by the gauge 11 is the sum of the axial force applied to the sample 9 without taking into account its deformation from the internal pressure, which is taken into account K-gain additional scale amplifier 15:

g

R

one.

§;

(2)

The sample strain signal from internal pressure is negative.

In this way, the stress of the axial deformation of the sample is compensated for by the internal pressure both in the control and in the measurement of the load on the sample.

The proposed device (unlike the known ones) allows testing samples of any size and cross section (round, square, etc.) from various materials within the power of the hydraulic cylinders without any re-equipment of the device.

Full pressure I9 force axial thrust expansion of the sample from the internal pressure in the control channel

allows the load to more accurately

produce and control axial

the load on the specimen, which adds the credibility of such tests.

The general principle of measurement and control of load and pressure, inherent in the proposed device, unlike the known ones, allows simulating the operation of elements and devices of pipelines in real conditions (endless pipeline) under static and slowly varying axial loads and pressures.

Claims (1)

Invention Formula A device for testing tubular specimens under two-component loading conditions, containing a load frame, a fixed grip fixed on the frame, a movable grip mounted on the frame with the possibility of moving relative to it, an axial force generating mechanism, in the form of a hydraulic cylinder, .. about yu 15 0 five In which the movable gripper is fixed, the internal pressure generating mechanism, made in the form of a hydraulic multiplier, a pressure gauge installed in the high pressure cavity of the multiplier, a pressure control unit whose input is connected to the pressure gauge, the first control unit whose input is connected to the output of the control unit pressure, and the output is connected to the control cavity of the multiplier, the axial force meter, the second control unit, the output of which is connected to the cavities of the hydraulic cylinder, ex In order to improve accuracy by eliminating the effect of deformation of the sample on the axial force measurement, it is equipped with a large-scale amplifier, to the input of which a pressure gauge is connected, an adder, to the first input of which an axial force gauge is connected, and to the second input - large-scale output an amplifier, an axial force control unit, the input of which is connected to the output of the adder, and the output to the input of the second control unit.