RU2402014C1 - Device for collisional flaw detection of materials - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: device for collisional flaw detection comprises a cylindrical vessel with striker installed in it, electronic unit with amplifier and indicator. Besides striker is made of rod, which is freely embraced by tension spring, one end of which is rigidly fixed in upper part of rod, and the other one - on vessel wall, at the same time in lower part of vessel coaxially to rod there is a freely arranged detachable spring-loaded striking pin, contacting with lower end surface of rod, in upper part of vessel there is a bushing with the possibility of its adjustment and fixation relative to vessel, in lower part of bushing there are handles fixed to hold rod in cocked position, in upper part of rod there are also handles fixed, besides in upper part of bushing there are longitudinal slots for free motion of handles as tension spring is cocked, on upper surface of rod there is a sensor of impact force measurement rigidly fixed, electronic unit is equipped with computer device, generator of reference signal, by analog-digital converter and sensitive sensors, at the same time inlets of amplifier are connected to sensitive sensors and sensor of impact force measurement, and outlet of amplifier is connected to analog-digital converter, outlet of program block is connected to generator of reference signal, outlet of which is connected to inlet of comparator of computer device, the second inlet of which is connected to outlet of analog-digital converter, and outlet of comparator is connected to inlet of computer device signal analyser, at the same time outlet of signal analyser is connected to indicator of computer device.

EFFECT: increased sensitivity of device, provision of possibility to control not just flaky materials, and simplification, reduction of weight and dimensions of device.

3 dwg

Description

The device relates to the field of flaw detection, in particular to devices for non-destructive testing of various materials, and can be used for flaw detection of both the materials themselves and their products (metal pipes and structures, sheet material, etc.).

A means for defectoscopy is known, which implements the method of free oscillations, containing a shock vibrator excited by an electromagnet, a receiver with a piezoelectric element and an amplifier with an indicator (Lange Yu.V., Ustinov E.G. Low-frequency acoustic defectoscope AD-60C, Defectoscopy, 1989, No. 1, pp. 12-15).

The disadvantages of this device are the relatively low sensitivity, as well as a significant level of noise arising from the operation of the device, the inconvenience of working with manual scanning.

The closest technical solution for the totality of essential features is a device for impact testing, containing a housing, a drummer located in it and an electronic unit with an amplifier and indicator (RF Patent No. 2164419 according to class G01N 29/04 dated 12.29.1998).

The disadvantage of this device is the relatively low sensitivity, due to the fact that the sensitivity depends on the density and reliability of the contact between the striker and the surface of the test product. In addition, the device contains a drive element to provide impact on the test material with a certain frequency, which complicates the design of the device.

The problem to which the claimed invention is directed, is to increase the sensitivity of the device, simplify the design, provide the ability to control not only layered materials and reduce weight and dimensions.

The problem is solved due to the fact that in the device for impact inspection, containing a cylindrical body with a drummer located in it, an electronic unit with an amplifier and an indicator, a drummer is made in the form of a rod freely covered by a tension spring, one end of which is rigidly fixed in the upper part of the rod and the other on the wall of the housing, while in the lower part of the housing coaxially with the rod is freely removable spring-loaded striker in contact with the lower end surface of the rod in the upper part of the housing the sleeve is located with the ability to adjust and fix it relative to the body, handles are fixed in the lower part of the sleeve for fixing the rod in the cocked position, handles are also fixed in the upper part of the shaft, and longitudinal grooves are made in the upper part of the sleeve for free movement of the handles when the tension spring is cocked, a shock force measuring sensor is rigidly fixed to the upper surface of the rod; the electronic unit is equipped with a computer device, a reference signal generator, an analog-to-digital converter, and sensing sensors, while the amplifier inputs are connected to sensitive sensors and a shock force measurement sensor, the amplifier output is connected to an analog-to-digital converter, and the computer device is equipped with a software unit whose inputs are connected to sensitive sensors, a shock force measurement sensor, and the output of the program block connected to a reference signal generator, the output of which is connected to the input of the comparator of the computer device, the second input of which is connected to the output of the analog-to-digital eobrazovatelya, and the comparator output is connected to the input of the signal analyzer computer device, wherein the signal analyzer is connected to the indicator output of the computer device.

Figure 1 presents a General view of the striker device for impact testing of materials.

Figure 2 presents a diagram of the electronic unit of the device for impact inspection.

Figure 3 presents the waveforms of the electrical signals of the sensors installed on the controlled product.

The device for impact defectoscopy comprises a cylindrical body 1, in which a hammer is placed in the form of a rod 2, covered by a tension spring 3, one end of which is rigidly fixed in the upper part of the rod, and the other on the wall of the body with screws 4 and 5. In the lower part of the body coaxial with the rod is a removable spring-loaded hammer 6, in contact with the lower end surface of the rod 2. In the upper part of the housing is a sleeve 7 with the ability to adjust and fix in height relative to the housing. This is achieved by the fact that the sleeve on the rod is detachably mounted using a threaded connection, and the position of the sleeve is fixed using the nut 8.

Handles 9 are fixed in the lower part of the sleeve for fixing the rod in the cocked position, and handles 10 are also fixed in the upper part of the shaft, and longitudinal grooves 11 are made in the upper part of the sleeve for free movement of the handles when the tension spring is cocked and grooves 12 for fixing the rod. The lower part of the body is equipped with a flange 13 mounted on the test material through an elastic (rubber) element 14. On the upper end surface of the rod, a sensor 15 is rigidly fixed to measure the impact force of the striker 6 on the surface of the test product.

The electronic unit contains a computer device 16, a reference signal generator 17, an amplifier 18, an analog-to-digital converter 19, and sensitive sensors 20 and 21. The computer device contains a comparator 22, a signal analyzer 23, a program unit 24, and an indicator 25. The amplifier inputs are connected to sensitive sensors 20 and 21 and with a sensor for measuring impact force 15. The output of the amplifier is connected to an analog-to-digital converter, and the output of the program unit is connected to the input of the reference signal generator, the output of which is connected to the compar input an amplifier, the other input of which is connected to the output of the analog-to-digital converter, the output of the comparator connected to the input of the signal analyzer, and its output with an indicator.

The proposed device for impact defectoscopy uses the local method of free vibrations, based on the impact excitation in a controlled object of freely damped elastic vibrations and the analysis of their spectrum. A sign of a defect is a change in the spectrum compared with the spectrum in the defect-free zones of the material or product.

The device operates as follows.

Before starting work, the flange 13 is mounted on the plane or surface of the test material or product. The installation is carried out in such a way that the firing pin 6 is located above the zone, on which the striker of the device will strike. To cock the spring 3, the handle 10 is lifted up along the grooves 11, stretching the spring 3 and lifting the rod by a certain value h, determined by the required value of the impact force on the surface of the material. After this, turning the handle 10 by 90 °, the rod 2 is fixed in the cocked state in the grooves 12. The rod 2 is released by turning the handle in the opposite direction and withdrawing it from the grooves 12 until the handle stops touch the grooves 11. Energy stored during the spring 3 stretching transmitted to the rod 2 and through its lower surface - to the hammer 6, which strikes the surface of the investigated material.

At the initial moment of contact of the striker with the surface of the material as a result of shock loading, waves are generated that propagate along the length of the test sample. The time dependence of the amplitude of such waves and their amplitude-frequency characteristic depends on the impact force of the striker, the elastic properties of its material, the properties of the material under study, and the violation of its structure (defects).

To exclude the possibility of repeated strikes of the striker 6 on the test product, the striker is spring loaded and is located at a distance of "N" from the striking surface. The indicated distance is selected either with the help of a nut fixed in the lower part of the housing, or with the thickness of the elastic gasket.

Possible repeated impacts between the ends of the rod and the striker transmit minor vibrations through the shock-absorbing layer 14, which do not significantly affect the characteristics of the dynamic processes under study.

The sensor 15, mounted on the upper part of the rod 2, allows you to determine the maximum acceleration (force) developed on the striker at the time of impact on the product.

Using the sensor 21 installed next to the impact zone, the initial signals are recorded on the test product (curve 1 in figure 3). From the sensor 20 mounted at a controlled distance, the signals shown in FIG. 3 are recorded (curve 2). The horizontal axis shows the time in milliseconds, the vertical axis shows the acceleration of the piezo-accelerometer sensor. Using various types of strikers, differing in material and shape, it is possible to form various characteristics of shock waves and vibrations in the tested product.

The signals received from the sensors are transmitted to the amplifier 18, block 19 and block 22, in which there is a comparison with the reference signal supplied from the reference signal generator 17 with further transmission to the signal analyzer 23. These actions are performed using the program unit 24 and the final signal is transmitted to indicator 25 of the computer device 16.

According to the obtained oscillograms, it is possible to determine the wave propagation time to the defect site and its velocity, and, consequently, the location of the defect.

The proposed device is compact, not difficult to operate and is not bulky. The use of single strokes increases the sensitivity by eliminating, in relation to the known, additional tools for analyzing a complex spectrum of signals, including vibrations under the influence of shock waves in the material and vibrations of the striker itself.

Claims (1)

A device for impact testing containing a cylindrical body with a drummer located in it, an electronic unit with an amplifier and an indicator, characterized in that the drummer is made in the form of a rod freely covered by a tension spring, one end of which is rigidly fixed in the upper part of the rod, and the other on the wall of the housing, while in the lower part of the housing coaxially with the rod is freely removable spring-loaded striker in contact with the lower end surface of the rod, in the upper part of the housing is a sleeve with adjustment and fixing it relative to the housing, handles are fixed in the lower part of the sleeve for fixing the rod in the cocked position, handles are also fixed in the upper part of the shaft, and longitudinal grooves are made in the upper part of the sleeve for free movement of the handles when the tension spring is cocked, on the upper surface of the shaft a shock force measuring sensor is rigidly fixed, the electronic unit is equipped with a computer device, a reference signal generator, an analog-to-digital converter, and sensitive sensors, when The amplifier inputs are connected to sensitive sensors and a shock force measuring sensor, and the amplifier output is connected to an analog-to-digital converter, the output of the program unit is connected to a reference signal generator, the output of which is connected to the input of a comparator of a computer device, the second input of which is connected to the output of analog-digital converter, and the comparator output is connected to the input of the signal analyzer of the computer device, while the output of the signal analyzer is connected to the indicator of the computer device wa.

Images