CN109884126A

CN109884126A - Crack propagation measuring system and method and its method of inspection and device

Info

Publication number: CN109884126A
Application number: CN201910134596.7A
Authority: CN
Inventors: 薛河; 魏其深; 倪陈强; 张亮; 徐鹏超
Original assignee: Xian University of Science and Technology
Current assignee: Xian University of Science and Technology
Priority date: 2019-02-23
Filing date: 2019-02-23
Publication date: 2019-06-14
Anticipated expiration: 2039-02-23
Also published as: CN109884126B

Abstract

The invention discloses crack propagation measuring system and method and its method of inspection and device, crack propagation measuring system includes constant-current source, direct current reverse circuit, amplifier module, singlechip controller, host computer, isolation circuit, electric current connecting line and voltage connecting wire；Verifying attachment includes fixinig plate crack length change system and single-chip microcontroller and relay group control module；Measurement method is direct current potential drop method, sample its potential fields in crack propagation change, the voltage drop at sample crackle both ends is gradually increased with the growth of crack length, and the crack propagation numerical value of measurement sample can be obtained by the potential difference at crackle both ends on measurement sample；The relationship between measured value and given value that the method for inspection passes through comparison test sample examines the accuracy of measuring system.Measuring system of the invention has the advantages that structure is simple, device is integrated, measurement accuracy is high, is easily carried, moderate, and verifying attachment of the invention has the advantages that at low cost and can reuse.

Description

Crack propagation measuring system and method and its method of inspection and device

Technical field

The invention belongs to engineering components safety analysis technique field, more particularly, to a kind of crack propagation measuring system and Method and its method of inspection and device.

Background technique

Many engineering components in the industry such as aviation, nuclear power, power and metallurgy, such as axis, crankshaft, connecting rod, gear, pressure Container, turbine blade etc., during one's term of military service due to the continuous variation of the adverse circumstances such as environment temperature and pressure, lead to these at it Components are subjected to mechanical stress caused by cyclic loading, and the variation also subject to temperature, pressure quasi-periodic causes Pulsating stress.Especially in the stress concentration portion position of components, micro-crack can be generated during long service, and fine fisssure A series of variations occur for the material property that the generation of line will lead to components, as intensity, rigidity are reduced.Micro-crack gradually accumulates It is tired to form macroscopic cracking and extend, material failure and destruction are ultimately caused, is not only completely lost after metal parts fracture Service ability, it is also possible to will cause weight huge economic loss and catastrophic accident.The 1970s, Sweden was at that time The breakage of 85 large ship structures is investigated, the result shows that because the destruction ratio that fatigue crack generates reaches 70.45%；186 bulk freighter marine accidents 1980-1996 are investigated by Lloyd's Register of Shipping, knot Fruit shows that the important reason that marine accident occurs is exactly that the fatigue strength deficiency of ship sinks to shipbreaking in the sea； Also researches show that the eighties, the air crash major accident due to caused by fatigue fracture, 100 times every year on average.In order to true The catastrophic failure that can not be retrieved will not occur for the crackle that guarantor's equipment and components exist or extending when in use, it is necessary to can Subcritical Crack Growth situation of the determination components leaned under fatigue condition, it is to determine that the characteristic in Parts service life refers to One of mark.What crack propagation measuring system generallyd use is the crack propagation measuring system based on DCPD method, and DCPD method is direct current Potential drop mensuration is the electric conductivity based on sample to measure crack length, and sample its potential fields in crack propagation become Change, the voltage drop at sample crackle both ends is gradually increased with the growth of crack length, can pass through the electricity at measurement sample crackle both ends Potential difference measures the crack propagation numerical value of sample to obtain.Currently, the domestic crack propagation measuring system based on DCPD method is Built by several instrument, have no the device of Highgrade integration and influence factor is more, cause measurement accuracy poor, volume compared with Greatly, inconvenient to carry, and be also temporarily to take to the verifying attachment of the accuracy of the crack propagation measuring system based on DCPD method It builds, there is no complete set and the verifying attachments that can reuse.

Summary of the invention

It is an object of the invention to overcome the deficiencies in the prior art described above, a kind of crack propagation measuring system is provided, Have the advantages that structure is simple, device is integrated, measurement accuracy is high, be easily carried, is moderate.

To achieve the above object, the technical solution adopted by the present invention is that: a kind of crack propagation measuring system, feature exist In: it is overturn including the constant-current source for exporting Constant Direct Current electric current, the Constant Direct Current electric current direction for exporting constant-current source Direct current reverse circuit, for will receive voltage signal amplification amplifier module, be used to convert received voltage analog signal to Digital signal and to digital signal carry out the singlechip controller of analytical calculation, the host computer for showing measured value, for every The isolation circuit that is electrically connected between disconnected constant-current source and singlechip controller, the electric current company for connect output Constant Direct Current electric current Wiring and for connecting the voltage connecting wire for inputting voltage signal to be measured, the constant-current source connect with external 24V battery and The current signal end of constant-current source is connect with the input terminal of direct current reverse circuit, and the output end and electric current of the direct current reverse circuit connect Wiring connects and Constant Direct Current electric current signal is transmitted to measurement sample connect with electric current connecting line, the voltage connecting wire and Amplifier module input connection and voltage connecting wire with measurement sample by connecting voltage signal being transmitted to amplifier module, it is described The output end of amplifier module and the input terminal of singlechip controller connect and will be transmitted to monolithic after the amplification of the voltage signal of acquisition Machine controller, the amplifier module are connect with external 12V battery, and the output end and host computer of the singlechip controller input End connects and shows the measurement numerical value after analytical calculation on host computer, the data sending terminal of the constant-current source and single-chip microcontroller control The data receiver of device processed connects and by constant-current source data signal transmission to singlechip controller, the data receiver of the constant-current source End connect to receive the order of singlechip controller with the data sending terminal of singlechip controller, the power end of the constant-current source and The power end of isolation circuit connection, the isolation circuit and singlechip controller connects and for preventing constant current source signal to monolithic Machine controller receives interfering for signal, and the singlechip controller connect with direct current reverse circuit and transmits overturning instruction The overturning of current direction is controlled to direct current reverse circuit.

Above-mentioned a kind of crack propagation measuring system, it is characterised in that: the isolation circuit includes that two models are The optocoupler 1 and optocoupler 2 of PC817, No. 1 pin of the optocoupler 1 connect with the end VCC of access circuit, No. 2 pins and single-chip microcontroller control The I/O mouth connection of device processed, the end the VCC connection of No. 3 pins and singlechip controller, the end the VCC connection of No. 4 pins and constant-current source, No. 1 pin of the optocoupler 2 connect with the end VCC, the connection of I/O mouth, No. 3 pins and the monolithic of No. 2 pins and singlechip controller The end the GND connection of machine controller, the end GND of No. 4 pins and constant-current source connect.

A kind of above-mentioned crack propagation measuring system, it is characterised in that: the electric current connecting line by electric current output lead and Electric current input lead composition, the voltage connecting wire are made of two conducting wires, and the direct current reverse circuit includes solid-state relay The transistor array of SSR1, solid-state relay SSR2, solid-state relay SSR3, solid-state relay SSR4 and model ULN2003A Column, No. 9 pins of the transistor array access external 5V battery, No. 1 pin and No. 2 pins with singlechip controller Instruction output end connection, No. 15 pins of the transistor array and No. 4 pins of solid-state relay SSR2 and solid-state relay No. 4 pins of SSR4 are all connected with, No. 16 pins draw with No. 4 pins of solid-state relay SSR1 and No. 4 of solid-state relay SSR3 Foot is all connected with, No. 3 pins of the solid-state relay SSR1, No. 3 pins of solid-state relay SSR2, solid-state relay SSR3 No. 3 pins of No. 3 pins and solid-state relay SSR4 access external 5V battery, and No. 2 of the solid-state relay SSR1 are drawn No. 2 pins of foot and solid-state relay SSR2 are connect with the electric current cathode output end of constant-current source, the solid-state relay SSR3 No. 1 pin and No. 1 pin of solid-state relay SSR4 connect with the electric current negative input of constant-current source, the solid-state relay No. 1 pin of device SSR1 and No. 2 pins of solid-state relay SSR4 are connect with electric current output lead, the solid-state relay No. 1 pin of SSR2 and No. 2 pins of solid-state relay SSR3 are connect with electric current input lead.

Above-mentioned crack propagation measuring system, it is characterised in that: the pad of the electric current output lead and measurement sample It is all larger than at a distance from the pad to measurement sample crackle of measurement sample to the distance of measurement sample crackle, electric current input lead The conducting wire of voltage connecting wire is at a distance from the pad to measurement sample crackle of measurement sample.

Above-mentioned crack propagation measuring system, it is characterised in that: the constant-current source is the program-controlled electric that model is ZXY-6005S Source.

The present invention also provides a kind of methods for carrying out crack propagation measurement using above system, which is characterized in that the party Method the following steps are included:

Step 1: the power switch of crack propagation measuring system is opened, by electric current output lead and electric current input lead point Other spot welding be connected to measurement sample crack surface two sides, by voltage connecting wire respectively spot welding be connected to measurement sample crackle two sides；

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source are arranged in host computer, host computer will Setting Constant Direct Current current value order is transmitted to the data receiver of constant-current source by the data sending terminal of singlechip controller, permanent Stream source exports the Constant Direct Current electric current of host computer setting, and constant dc is streamed to direct current reverse circuit, direct current reverse circuit Do not stop reset current direction under the control of singlechip controller, does not stop the constant dc circulation overcurrent output lead of overturning Direct current reverse circuit is flow to through overcurrent input lead to measurement sample, and after measurement sample output；

Step 3: amplifier module receives the measurement voltage signal of voltage connecting wire transmission and puts the voltage signal of acquisition Greatly, and the voltage signal of amplification is transmitted in singlechip controller by amplifier module, and singlechip controller is by received voltage-mode Quasi- signal is converted into digital signal and carries out analytical calculation, and the data after analytical calculation are simultaneously uploaded to upper by singlechip controller Machine, operator can check the crack extending length data of measurement sample in host computer,

The analytical calculation formula of singlechip controller are as follows:

A=15.153*u²+83.408u+3.2361

Wherein, a is the crack extending length for measuring sample and unit is mm, u be the voltage signal data of measurement sample and Unit is μ V；

The crack propagation DATA REASONING of measurement sample finishes.

Invention further provides it is a kind of it is at low cost, can reuse and the crack propagation of above-mentioned measuring system is measured quasi- The verifying attachment that exactness is tested, it is characterised in that: the fixinig plate crack length including being fixed with multiple test samples changes System and single-chip microcontroller for control test sample measurement order and relay group control module, the single-chip microcontroller and relay group Control module connect with fixinig plate crack length change system and is used to select to need the test sample of output voltage signal, described Electric current output lead and electric current input lead are connect and with the test sample in fixinig plate crack length change system direct current Current signal after reverse circuit overturning is transmitted separately in the test sample in fixinig plate crack length change system, the list Piece machine connect with voltage connecting wire with the output end of relay group control module and test sample voltage signal is transmitted to amplifier Module.

Above-mentioned verifying attachment, it is characterised in that: the fixinig plate crack length change system includes ten test samples With five connecting terminals, five connecting terminals are four connecting terminals, and five connecting terminals are respectively terminals Son 1, connecting terminal 2, connecting terminal 3, connecting terminal 4 and connecting terminal 5, described ten test samples are that 304 steel examine examination Sample, the crack extending length of described ten test samples is known and is arranged successively from short to long according to crack length, the inspection Test sample 1 crack length is most short and the crack length longest of test sample 10, the other end of the electric current output lead and inspection Test the crack surface side spot welding connection of sample 1, the crack surface other side of the test sample 1 and the crack surface one of test sample 2 Side is connected with conducting wire spot welding, the crack surface other side of the test sample 2 and the crack surface side conducting wire spot welding of test sample 3 Connection, the crack surface other side of the test sample 3 are connect with the crack surface side of test sample 4 with conducting wire spot welding, the inspection The crack surface other side for testing sample 4 is connect with the crack surface side of test sample 5 with conducting wire spot welding, and the test sample 5 is split The line face other side is connect with the crack surface side of test sample 6 with conducting wire spot welding, the crack surface other side of the test sample 6 with The crack surface side of test sample 7 is connected with conducting wire spot welding, the crack surface other side and the test sample 8 of the test sample 7 Crack surface side is connected with conducting wire spot welding, and the crack surface other side of the test sample 8 and the crack surface side of test sample 9 are used Conducting wire spot welding connection, the crack surface other side of the test sample 9 and the crack surface side of test sample 10 are connected with conducting wire spot welding It connects, the crack surface other side of the test sample 10 is connect with electric current input lead；

The crackle side of the test sample 1 is connect with the interface of front end 1 of connecting terminal 1, and the test sample 1 is split The line other side is connect with the interface of front end 2 of connecting terminal 1, the crackle side of the test sample 2 and the front end of connecting terminal 2 No. 1 interface connection, the crackle other side of the test sample 2 are connect with the interface of front end 2 of connecting terminal 2, the inspection examination The crackle side of sample 3 is connect with the interface of front end 1 of connecting terminal 3, the crackle other side of the test sample 3 and connecting terminal The 3 interface connection of front end 2, the crackle side of the test sample 4 are connect with the interface of front end 1 of connecting terminal 4, the inspection The crackle other side for testing sample 4 is connect with the interface of front end 2 of connecting terminal 4, the crackle side of the test sample 5 and wiring The interface connection of front end 1 of terminal 5, the crackle other side of the test sample 5 are connect with the interface of front end 2 of connecting terminal 5, The crackle side of the test sample 6 is connect with the interface of rear end 4 of connecting terminal 5, the crackle other side of the test sample 6 It is connect with the interface of rear end 3 of connecting terminal 5, the crackle side of the test sample 7 and the interface of rear end 4 of connecting terminal 4 Connection, the crackle other side of the test sample 7 are connect with the interface of rear end 3 of connecting terminal 4, and the test sample 8 is split Line side is connect with the interface of rear end 4 of connecting terminal 3, the crackle other side of the test sample 8 and the rear end of connecting terminal 3 No. 3 interface connections, the crackle side of the test sample 9 are connect with the interface of rear end 4 of connecting terminal 2, the test sample 9 The crackle other side connect with the interface of rear end 3 of connecting terminal 2, the crackle side of the test sample 10 and connecting terminal 1 Rear end No. 4 interfaces connection, the crackle other side of the test sample 10 is connect with the interface of rear end 3 of connecting terminal 1.

Above-mentioned verifying attachment, it is characterised in that: the single motor and relay group control module by No. 8 relay group A, The singlechip chip of No. 8 relay group B, No. 8 relay group C and model STM32F103C8T6 composition, 8 tunnel after The IN1 pin of electric appliance A successively draws with the A6 pin of singlechip chip, A12 pin, No. A11 respectively to IN8 pin Foot, A8 pin, B15 pin, B14 pin, B13 pin are connected with B12 pin, the IN1 of No. 8 relay B Number pin to IN8 pin successively respectively with the A5 pin of singlechip chip, A4 pin, B5 pin, B6 pin, B7 Number pin, B8 pin, B11 pin are connected with B9 pin, the IN1 pin of No. 8 relay C to IN4 pin It is successively connect respectively with the B10 pin of singlechip chip, B1 pin, B0 pin and A7 pin, No. 8 relay Group the end VCC of A, the end VCC of No. 8 relay group B, No. 8 relay group C the end VCC connect with the 5v pin of singlechip chip, The end GND of No. 8 relay group A, the end GND of No. 8 relay group B, No. 8 relay group C the end GND and singlechip chip The connection of the end GND, the singlechip chip connect with the input terminal of amplifier module；

The interface of front end 3 of the connecting terminal 1 is connect with No. 1 pin of the 10B of No. 8 relay group C, front end 4 connects It mouthful is connect with No. 1 pin of the 10A of No. 8 relay group C, No. 1 pin company of the 1A of the interface of rear end 1 and No. 8 relay group A It connects, the interface of rear end 2 is connect with No. 1 pin of the 1B of No. 8 relay group A；The interface of front end 3 of the connecting terminal 2 and 8 tunnels No. 1 pin of the 9B of relay group C connects, the interface of front end 4 is connect with No. 1 pin of the 9A of No. 8 relay group C, rear end 1 Interface connect with No. 1 pin of the 2A of No. 8 relay group A, No. 1 pin of the 2B of the interface of rear end 2 and No. 8 relay group A connect It connects；The interface of front end 3 of the connecting terminal 3 is connect with No. 1 pin of the 8B relay of No. 8 relay group B, front end 4 connects Mouth is connect with No. 1 pin of the 8A of No. 8 relay group B, the interface of rear end 1 is connect with No. 1 pin of the 3A of No. 8 relay group A, The interface of rear end 2 is connect with No. 1 pin of the 3B of No. 8 relay group A；The interface of front end 3 of the connecting terminal 4 and 8 tunnels after No. 1 pin connection of the 7B of electric appliance group B, the interface of front end 4 is connect with No. 1 pin of the 7A of No. 8 relay group B, rear end 1 connects Mouth is connect with No. 1 pin of the 4A of No. 8 relay group A, the interface of rear end 2 is connect with No. 1 pin of the 4B of No. 8 relay group A； The interface of front end 3 of the connecting terminal 5 connect with No. 1 pin of the 6B of No. 8 relay group B, the interface of front end 4 and 8 tunnels after No. 1 pin connection of the 6A of electric appliance group B, the interface of rear end 1 is connect with No. 1 pin of the 5A of No. 8 relay group B, rear end 2 connects Mouth is connect with No. 1 pin of the 5B of No. 8 relay group B；No. 2 pins of the 1A of No. 8 relay group A, No. 8 relay group A No. 2 pins of 2A, No. 2 pins of 3A of No. 8 relay group A, No. 2 pins of the 4A of No. 8 relay group A, No. 8 relay groups No. 2 pins of the 5A of B, No. 2 pins of the 6A of No. 8 relay group B, No. 8 relay group B 7A No. 2 pins, No. 8 relays No. 2 pins of the 10A of No. 2 pins of the 8A of group B, No. 2 pins of the 9A of No. 8 relay group C and No. 8 relay group C are connected to Together, the 3B of No. 2 pins of the 1B of No. 8 relay group A, No. 2 pins of the 2B of No. 8 relay group A, No. 8 relay group A No. 2 pins, No. 2 pins of 4B of No. 8 relay group A, No. 2 pins of the 5B of No. 8 relay group B, No. 8 relay group B No. 2 pins of 6B, No. 2 pins of the 7B of No. 8 relay group B, No. 2 pins of the 8B of No. 8 relay group B, No. 8 relay group C No. 2 pins of 9B and No. 2 pins of 10B of No. 8 relay group C link together.

In addition, the present invention also provides it is a kind of using above-mentioned verifying attachment test measuring system On Crack Propagation measure it is quasi- The method of exactness, which is characterized in that method includes the following steps:

Step 1: the power switch of the verifying attachment of crack propagation measuring system and crack propagation measuring system is opened It opens；

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source are arranged in host computer, host computer will Setting Constant Direct Current current value order is transmitted to the data receiver of constant-current source by the data sending terminal of singlechip controller, permanent Stream source exports the Constant Direct Current electric current of host computer setting, and constant dc is streamed to direct current reverse circuit, direct current reverse circuit Do not stop reset current direction under the control of singlechip controller, does not stop the constant dc circulation overcurrent output lead of overturning It is transmitted in ten test samples of fixinig plate crack length change system, and flows back to direct current overturning electricity through overcurrent input lead Lu Zhong, ten test samples are that the crack length of the test sample of known crack length and ten test samples is unequal；

Step 3: finger of the singlechip chip of single-chip microcontroller and relay group control module according to 1 circuit of continuity check sample It enables the corresponding No. 8 relay group of control that will connect the voltage signal circuit of test sample 1 and voltage signal is transmitted to amplifier The voltage signal for acquiring test sample 1 is transmitted to amplifier module by module, singlechip chip, and amplifier module believes received voltage Number amplification after by voltage signal transmit singlechip controller in, received analog voltage signal is converted number by singlechip controller Word signal simultaneously carries out analytical calculation, and the data after analytical calculation are uploaded to host computer by singlechip controller, and operator can be upper The crack extending length data of test sample 1 are checked in the machine of position,

The analytical calculation formula of singlechip controller are as follows:

A=15.153*u²+83.408u+3.2361

Wherein, a is the crack extending length of test sample and unit is mm, and u is the voltage signal of the test sample of measurement Data and unit are μ V；

It is acquired Step 4: repeating step 3 and being respectively completed test sample 2 to the data of test sample 10；

Step 5: by the data of the test sample 1 of acquisition to test sample 10 respectively and known to corresponding test sample Crack data is compared, and is examined by the relationship between the test data and known crack data of ten test samples of comparison The accuracy of measurement of crack propagation measuring system.

Compared with the prior art, the present invention has the following advantages:

1, the input current of crack propagation measuring system of the invention using Constant Direct Current electric current as measurement sample, avoids The influence of alternating current alternating voltage remaining after rectifying and wave-filtering and electric current skin effect to actual signal, improves measurement The measurement accuracy of system.

2, crack propagation measuring system of the invention is formed straight using a transistor array and four solid-state relays The direction of input current is not stopped to overturn by stream reverse circuit, is eliminated electric current input lead and is measured the contact resistance between sample Interference of the thermoelectrical potential of generation to output voltage signal, and the amplified bias voltage of voltage signal for eliminating output is to true The influence of data improves the measurement accuracy of measuring system.

3, crack propagation measuring system of the invention uses the design method of internal module, system over all Integration, Have the advantages that measurement accuracy it is high, it is easy to operate, easy to carry, automatically control, and be suitable for high temperature and pressure measurement environment, For example nuclear power primary coolant circuit pipe, nuclear-power reactor autoclave, chemical reaction kettle etc. will be monitored but monitor the ground having difficulties Side can be used, and solve the problems, such as that the metallic conduit crackle in high temperature and high pressure environment is difficult to measure.

4, the design that isolation circuit is increased in crack propagation measuring system of the invention, has successfully separated constant-current source and list Electrical connection between piece machine controller effectively avoids interference of the constant-current source to the acquisition signal of singlechip controller.

5, it is arranged in the fixinig plate crack length change system in the verifying attachment of crack propagation measuring system of the invention The test sample of ten different crack lengths, and ten test samples are placed according to the sequence of crack length from small to large, Therefore, ten test samples can be alternative to be stretched using Fatigue elongation machine with the crack propagation process of analogue measurement sample It measures crack propagation situation, reduces the cost of purchase Fatigue elongation machine, eliminating can in Fatigue elongation machine operation and operation The danger that can be generated, a possibility that providing experiment for the temporarily powerless researcher for buying Fatigue elongation machine.

6, ten in the fixinig plate crack length change system in the verifying attachment of crack propagation measuring system of the invention The entire scope that the numberical range of the crack length of a test sample covers the crack propagation of measurement sample therefore can be complete The whole comprehensive accuracy for examining crackle measuring system, and fixinig plate crack length change system does not need to supply by outside Electricity, it is only necessary to the extracting power supply cord from crack monitoring system not only has the advantages that structure is simple, cost is relatively low, but also It can also reuse.

7, the present invention has broken the domestic crack propagation measuring system based on DCPD method not integrated, has made without repeatable The status of the verifying attachment of crack propagation measuring system, and from electrification inside crack propagation measuring system of the invention Source has the advantages that voltage is low, low in energy consumption, noise is small, small power consumption.

Below by drawings and examples, the present invention is described in further detail.

Detailed description of the invention

Fig. 1 is the energization schematic diagram of 304 steel curved beams of the invention.

Fig. 2 is the schematic block circuit diagram of crack propagation measuring system of the present invention.

Fig. 3 is the circuit diagram of crack propagation measuring system of the present invention.

Fig. 4 is the connection figure between crack propagation measuring system of the present invention and measurement sample.

Fig. 5 is the experimental data that the test sample crack extending length of fixinig plate crack length change system of the present invention measures Figure.

Fig. 6 is the schematic block circuit diagram of the verifying attachment of crack propagation measuring system of the present invention.

Fig. 7 is the connection block diagram of the verifying attachment of crack propagation measuring system of the present invention and measuring system.

Fig. 8 is the circuit diagram of fixinig plate crack length change system of the present invention.

Fig. 9 is the circuit diagram of single-chip microcontroller of the present invention and relay group control module.

Figure 10 is the circuit diagram that relay group is connect with fixinig plate crackle change system.

Figure 11 is the connection circuit diagram of the verifying attachment of crack propagation measuring system of the present invention and measuring system.

Description of symbols:

1-constant-current source；2-direct current reverse circuits；

3-fixinig plate crack length change systems；4-single-chip microcontrollers and relay group control module；

5-amplifier modules；6-singlechip controllers；7-host computers；

8-isolation circuits；9-measurement samples；10-electric current connecting lines；

10-1-electric current output lead；10-2-electric current input lead；11-voltage connecting wires；

12-24V batteries；13-12V batteries；14-5V batteries；

15—VCC。

Specific embodiment

As shown in Figure 1, crackle measuring system of the present invention is surveyed on the basis of based on DCPD (direct current potential drop) method Amount, DCPD method is the electric conductivity based on metal component to measure crack length, and containing on precracked specimen, potential fields are samples The function of geometry and crack length, sample potential fields change when crack propagation, can get by measuring this variation Crack propagation situation, when passing through constant electric current (I) on 304 samples, since to pass through electric current transversal for the presence of crackle Face reduces, and so as to cause the increase of material resistance itself, i.e. measurement current potential (V) increases with sample crack length and increased.

As shown in Figures 2 and 3, a kind of crack propagation measuring system, including the constant-current source for exporting Constant Direct Current electric current 1, the direct current reverse circuit 2 of the Constant Direct Current electric current direction overturning for exporting constant-current source 1, be used to receive voltage signal and put Big amplifier module 5, for converting digital signal for received voltage analog signal and carrying out analytical calculation to digital signal The singlechip controller 6, host computer 7 for showing measured value, electric for separating between constant-current source 1 and singlechip controller 6 Gas connection isolation circuit 8, for connect output Constant Direct Current electric current electric current connecting line 10 and for connect input it is to be measured The voltage connecting wire 11 of voltage signal, the constant-current source 1 is connect with external 24V battery 12 and the current signal end of constant-current source 1 It is connect with the input terminal of direct current reverse circuit 2, the output end of the direct current reverse circuit 2 connect with electric current connecting line 10 and will be permanent Determine DC current signal and is transmitted to the measurement sample 9 connecting with electric current connecting line 10, the voltage connecting wire 11 and amplifier module 5 Input terminal connection and voltage connecting wire 11 with measurement sample 9 by connecting voltage signal being transmitted to amplifier module 5, the amplifier The output end of module 5 connect with the input terminal of singlechip controller 6 and will be transmitted to single-chip microcontroller after the amplification of the voltage signal of acquisition Controller 6, the amplifier module 5 are connect with external 12V battery 13, the output end and host computer 7 of the singlechip controller 6 Input terminal is connected and is shown the measurement numerical value after analytical calculation on host computer 7, the data sending terminal and list of the constant-current source 1 The data receiver of piece machine controller 6 connects and by 1 data signal transmission of constant-current source to singlechip controller 6, the constant-current source 1 Data receiver connect with the data sending terminal of singlechip controller 6 to receive the order of singlechip controller 6, the constant current The power end in source 1 is connect with isolation circuit 8, and the isolation circuit 8 connect with the power end of singlechip controller 6 and for preventing 1 signal of constant-current source receives signal to singlechip controller 6 and interferes, and the singlechip controller 6 connects with direct current reverse circuit 2 It connects and overturning instruction is transmitted to direct current reverse circuit 2 to control the overturning of current direction.

As shown in figure 3, the isolation circuit 8 includes the optocoupler 1 and optocoupler 2 that two models are PC817, the optocoupler 1 No. 1 pin connect with VCC the voltage of circuit (access) 15 ends of access circuit, the I/O of No. 2 pins and singlechip controller 6 Mouth connection, No. 3 pins are connect with the end VCC of singlechip controller 6, No. 4 pins are connect with the end VCC of constant-current source 1, the optocoupler 2 No. 1 pin is connect with VCC (voltage of access circuit) 15 ends, No. 2 pins are connect with the I/O of singlechip controller 6 mouth, No. 3 The GND (ground wire) of the connection of the end the GND (ground wire) of pin and singlechip controller 6, No. 4 pins and constant-current source 1, which is held, to be connected.

As shown in figure 3, the electric current connecting line 10 is made of electric current output lead 10-1 and electric current input lead 10-2, institute It states voltage connecting wire 11 to be made of two conducting wires, the direct current reverse circuit 2 includes solid-state relay SSR1, solid-state relay The transistor array of SSR2, solid-state relay SSR3, solid-state relay SSR4 and model ULN2003A, the transistor array No. 9 pins access 14, No. 1 pins of external 5V battery and No. 2 pins with the instruction output end of singlechip controller 6 connect It connects, No. 4 pins of No. 15 pins of the transistor array and No. 4 pins of solid-state relay SSR2 and solid-state relay SSR4 It is all connected with, No. 16 pins are all connected with No. 4 pins of solid-state relay SSR1 and No. 4 pins of solid-state relay SSR3, described No. 3 pins of solid-state relay SSR1, No. 3 pins of solid-state relay SSR2, No. 3 pins of solid-state relay SSR3 and solid-state No. 3 pins of relay SSR4 access external 5V battery 14, No. 2 pins and solid-state relay of the solid-state relay SSR1 No. 2 pins of device SSR2 are connect with the electric current cathode output end of constant-current source 1, No. 1 pin of the solid-state relay SSR3 and No. 1 pin of solid-state relay SSR4 is connect with the electric current negative input of constant-current source 1, and the 1 of the solid-state relay SSR1 No. 2 pins of number pin and solid-state relay SSR4 are connect with electric current output lead 10-1, and the 1 of the solid-state relay SSR2 No. 2 pins of number pin and solid-state relay SSR3 are connect with electric current input lead 10-2.

As shown in figure 4, the electric current output lead 10-1 and measurement sample 9 pad to measure 9 crackle of sample away from Pad from, electric current input lead 10-2 and measurement sample 9 is all larger than voltage connecting wire 11 at a distance from 9 crackle of sample to measuring Conducting wire with measurement sample 9 pad to measure 9 crackle of sample at a distance from.

In the present embodiment, the constant-current source 1 is the programmable power supply that model is ZXY-6005S.

In conjunction with Fig. 4, the measurement method of crack propagation the following steps are included:

Step 1: opening the power switch of crack propagation measuring system, electric current output lead 10-1 and electric current input are led Spot welding is connected to the crack surface two sides for measuring sample 9 to line 10-2 respectively, and by voltage connecting wire 11, spot welding is connected to measurement sample 9 respectively Crackle two sides；

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source 1, host computer 7 are arranged in host computer 7 Setting Constant Direct Current current value order is transmitted to the data receiver of constant-current source 1 by the data sending terminal of singlechip controller 6 End, constant-current source 1 export the Constant Direct Current electric current that host computer 7 is set, and constant dc is streamed to direct current reverse circuit 2, direct current Reverse circuit 2 does not stop reset current direction under the control of singlechip controller 6, and the constant dc stream for not stopping overturning passes through electricity Stream output lead 10-1 is transmitted in measurement sample 9, and is flow to directly after measurement sample output through overcurrent input lead 10-2 Flow reverse circuit 2；

Step 3: amplifier module 5 receives the measurement voltage signal of the transmission of voltage connecting wire 11 and believes the voltage of acquisition Number amplification, and the voltage signal of amplification is transmitted in singlechip controller 6 by amplifier module 5, and singlechip controller 6 will be received Voltage analog signal is converted into digital signal and carries out analytical calculation, and singlechip controller 6 simultaneously will be in the data after analytical calculation Host computer 7 is reached, operator can check the crack extending length data of measurement sample 9 in host computer 7,

The analytical calculation formula of singlechip controller 6 are as follows:

A=15.153*u²+83.408u+3.2361

Wherein, a is the crack extending length for measuring sample 9 and unit is mm, and u is the voltage signal data for measuring sample 9 And unit is μ V；

The crack propagation DATA REASONING of measurement sample 9 finishes.

Crack propagation measuring system of the invention has been broken to measure there are no integrated crack propagation at home at present The status of system, therefore, the accuracy of On Crack Propagation measuring system and the inspection of measurement reproducibility are also extremely important.Of the invention The verifying attachment of crack propagation measuring system is even more domestic initiation, this verifying attachment greatly improves crack propagation measurement system The measurement accuracy of system, in the development work of verifying attachment early period, the measurement number of the verifying attachment of On Crack Propagation measuring system According to being analyzed, the feasibility of this device is demonstrated.The test sample crack propagation of its fixinig plate crack length change system The experimental data of linear measure longimetry is as shown in figure 5, as seen from Figure 5, the real data and given data of corresponding test sample Between error amount within the scope of the measurement accuracy of measuring system, therefore the accurate of crack propagation system is examined with this device Degree and measurement reproducibility are feasible.

As shown in Figure 6 and Figure 7, the verifying attachment that the accuracy of On Crack Propagation measuring system is examined, including be fixed with more The fixinig plate crack length change system 3 of a test sample and single-chip microcontroller and relay for control test sample measurement order Group control module 4, the single-chip microcontroller connect and are used for relay group control module 4 with fixinig plate crack length change system 3 Selection needs the test sample of output voltage signal, the electric current output lead 10-1 and electric current input lead 10-2 and fixinig plate Current signal after test sample in crack length change system 3 connects and direct current reverse circuit 2 is overturn is transmitted separately to In test sample in fixinig plate crack length change system 3, the single-chip microcontroller and 4 output end of relay group control module and electricity Pressure connecting line 11 connects and the voltage signal of test sample is transmitted to amplifier module 5.

As shown in figure 8, the fixinig plate crack length change system 3 includes ten test samples and five connecting terminals, Five connecting terminals are four connecting terminals, and five connecting terminals are respectively connecting terminal 1, connecting terminal 2, connect Line terminals 3, connecting terminal 4 and connecting terminal 5, described ten test samples are 304 steel test samples, described ten inspection examinations The crack extending length of sample is known and is arranged successively from short to long according to crack length, the crack length of the test sample 1 Most short and test sample 10 crack length longest, the other end of the electric current output lead 10-1 and the crackle of test sample 1 Face side spot welding connection, the crack surface other side of the test sample 1 and the crack surface side of test sample 2 are connected with conducting wire spot welding It connects, the crack surface other side of the test sample 2 is connect with the crack surface side of test sample 3 with conducting wire spot welding, the inspection The crack surface other side of sample 3 is connect with the crack surface side of test sample 4 with conducting wire spot welding, the crackle of the test sample 4 The face other side is connect with the crack surface side of test sample 5 with conducting wire spot welding, the crack surface other side of the test sample 5 and inspection Test the crack surface side conducting wire spot welding connection of sample 6, the crack surface other side of the test sample 6 and splitting for test sample 7 Line face side is connected with conducting wire spot welding, and the crack surface side of the crack surface other side of the test sample 7 and test sample 8 is with leading Line spot welding connection, the crack surface other side of the test sample 8 are connect with the crack surface side of test sample 9 with conducting wire spot welding, The crack surface other side of the test sample 9 is connect with the crack surface side of test sample 10 with conducting wire spot welding, the inspection examination The crack surface other side of sample 10 is connect with electric current input lead 10-2；

As shown in figure 9, the single motor and relay group control module 4 are by No. 8 relay group A, No. 8 relay group B, 8 The singlechip chip of road relay group C and a model STM32F103C8T6 composition, No. IN1 of No. 8 relay A are drawn Foot to IN8 pin successively respectively with the A6 pin of singlechip chip, A12 pin, A11 pin, A8 pin, B15 Number pin, B14 pin, B13 pin are connected with B12 pin, and the IN1 pin of No. 8 relay B draws to No. IN8 Foot successively draws with the A5 pin of singlechip chip, A4 pin, B5 pin, B6 pin, B7 pin, No. B8 respectively Foot, B11 pin are connected with B9 pin, the IN1 pin of No. 8 relay C to IN4 pin successively respectively with monolithic B10 pin, B1 pin, the B0 pin of machine core piece are connected with A7 pin, the end VCC, 8 tunnels of No. 8 relay group A The end VCC of relay group B, No. 8 relay group C the end VCC connect with the 5v pin of singlechip chip, No. 8 relay Group the end GND of A, the end GND of No. 8 relay group B, No. 8 relay group C the end GND connect with the end GND of singlechip chip, The singlechip chip is connect with the input terminal of amplifier module 5；

As shown in Figure 10, No. 1 pin of the 10B of the interface of the front end of the connecting terminal 13 and No. 8 relay group C connect It connects, the interface of front end 4 is connect with No. 1 pin of the 10A of No. 8 relay group C, the 1A of the interface of rear end 1 and No. 8 relay group A The connection of No. 1 pin, the interface of rear end 2 connect with No. 1 pin of the 1B of No. 8 relay group A；The front end 3 of the connecting terminal 2 Number interface connect with No. 1 pin of the 9B of No. 8 relay group C, No. 1 pin of the 9A of the interface of front end 4 and No. 8 relay group C It connects, the interface of rear end 1 is connect with No. 1 pin of the 2A of No. 8 relay group A, the 2B of the interface of rear end 2 and No. 8 relay group A No. 1 pin connection；No. 1 pin of the 8B relay of the interface of front end 3 of the connecting terminal 3 and No. 8 relay group B connects It connects, the interface of front end 4 is connect with No. 1 pin of the 8A of No. 8 relay group B, the 3A of the interface of rear end 1 and No. 8 relay group A No. 1 pin connection, the interface of rear end 2 are connect with No. 1 pin of the 3B of No. 8 relay group A；The front end of the connecting terminal 43 Interface connect with No. 1 pin of the 7B of No. 8 relay group B, No. 1 pin of the 7A of the interface of front end 4 and No. 8 relay group B connect It connects, the interface of rear end 1 is connect with No. 1 pin of the 4A of No. 8 relay group A, the 4B of the interface of rear end 2 and No. 8 relay group A No. 1 pin connection；The interface of front end 3 of the connecting terminal 5 connect with No. 1 pin of the 6B of No. 8 relay group B, front end 4 Interface connect with No. 1 pin of the 6A of No. 8 relay group B, No. 1 pin of the 5A of the interface of rear end 1 and No. 8 relay group B connect It connects, the interface of rear end 2 is connect with No. 1 pin of the 5B of No. 8 relay group B；No. 2 pins, 8 of the 1A of No. 8 relay group A No. 2 pins of the 2A of road relay group A, No. 2 pins of the 3A of No. 8 relay group A, No. 8 relay group A 4A No. 2 pins, No. 2 pins of the 5A of No. 8 relay group B, No. 2 pins of the 6A of No. 8 relay group B, No. 8 relay group B No. 2 of 7A draw Foot, No. 2 pins of the 8A of No. 8 relay group B, No. 8 relay group C 9A No. 2 pins and No. 8 relay group C 10A 2 Number pin links together, No. 2 pins of the 1B of No. 8 relay group A, No. 2 pins of the 2B of No. 8 relay group A, 8 tunnels No. 2 pins of the 3B of relay group A, No. 2 pins of the 4B of No. 8 relay group A, No. 8 relay group B 5B No. 2 pins, 8 No. 2 pins of the 6B of road relay group B, No. 2 pins of the 7B of No. 8 relay group B, No. 8 relay group B 8B No. 2 pins, No. 2 pins of the 10B of No. 2 pins of the 9B of No. 8 relay group C and No. 8 relay group C link together.

In conjunction with Fig. 7 and Figure 11, the method for inspection of measuring system On Crack Propagation accuracy of measurement, comprising the following steps:

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source 1, host computer 7 are arranged in host computer 7 Setting Constant Direct Current current value order is transmitted to the data receiver of constant-current source 1 by the data sending terminal of singlechip controller 6 End, constant-current source 1 export the Constant Direct Current electric current that host computer 7 is set, and constant dc is streamed to direct current reverse circuit 2, direct current Reverse circuit 2 does not stop reset current direction under the control of singlechip controller 6, and the constant dc stream for not stopping overturning passes through electricity Stream output lead is transmitted in ten test samples of fixinig plate crack length change system 3, and through overcurrent input lead 10- 2 flow back in direct current reverse circuit 2, and ten test samples are the test sample of known crack length and the crackle of ten test samples Length is unequal；

Step 3: single-chip microcontroller and the singlechip chip of relay group control module 4 are according to connection examination 1 circuit of test sample Instruction controls corresponding No. 8 relay group and connects the voltage signal circuit of test sample 1 and by the voltage signal of test sample 1 It is transmitted to amplifier module 5, amplifier module 5 transmits voltage signal in singlechip controller 6 after amplifying the voltage signal of acquisition, Singlechip controller 6 converts digital signal for received analog voltage signal and carries out analytical calculation, and singlechip controller 6 will Data after analytical calculation are uploaded to host computer 7, and operator can check the crack extending length of test sample 1 in host computer 7 Data,

The analytical calculation formula of singlechip controller 6 are as follows:

A=15.153*u²+83.408u+3.2361

Expand because test sample 1 can simulate crackle of sample under the action of Fatigue elongation machine to test sample 10 Situation is opened up, therefore the measurement data of test sample 1 to test sample 10 after tested can also be analyzed to simulate fatigue The experiment conclusion of stretching-machine.

The above is only presently preferred embodiments of the present invention, is not intended to limit the invention in any way, it is all according to the present invention Technical spirit any simple modification, change and equivalent structure transformation to the above embodiments, still fall within skill of the present invention In the protection scope of art scheme.

Claims

1. a kind of crack propagation measuring system, it is characterised in that: including the constant-current source (1) for exporting Constant Direct Current electric current, use It is put in the direct current reverse circuit (2) for the Constant Direct Current electric current direction overturning for exporting constant-current source (1), for voltage signal will to be received Big amplifier module (5), for converting digital signal for received voltage analog signal and carrying out analysis meter to digital signal The singlechip controller (6) of calculation, the host computer (7) for showing measured value, for separating constant-current source (1) and singlechip controller (6) isolation circuit (8) that is electrically connected between, the electric current connecting line (10) for connecting output Constant Direct Current electric current and for connecting The voltage connecting wire (11) for inputting voltage signal to be measured is connect, the constant-current source (1) connect with external 24V battery (12) and perseverance The current signal end in stream source (1) is connect with the input terminal of direct current reverse circuit (2), the output end of the direct current reverse circuit (2) It is connect with electric current connecting line (10) and Constant Direct Current electric current signal is transmitted to the measurement sample connecting with electric current connecting line (10) (9), the voltage connecting wire (11) connect with amplifier module (5) input terminal and voltage connecting wire (11) by with measurement sample (9) voltage signal is transmitted to amplifier module (5) by connection, output end and singlechip controller (6) of the amplifier module (5) Input terminal connection and will the voltage signal of acquisition amplification after be transmitted to singlechip controller (6), the amplifier module (5) with it is external 12V battery (13) connection, the output end of the singlechip controller (6) connect with host computer (7) input terminal and by analysis meter Measurement numerical value after calculation is shown on host computer (7), data sending terminal and singlechip controller (6) of the constant-current source (1) Data receiver connection and by constant-current source (1) data signal transmission to singlechip controller (6), the data of the constant-current source (1) Receiving end connect to receive the order of singlechip controller (6), the constant-current source with the data sending terminal of singlechip controller (6) (1) power end is connect with isolation circuit (8), and the isolation circuit (8) connect and uses with the power end of singlechip controller (6) It is interfered in preventing constant-current source (1) signal from receiving signal to singlechip controller (6), the singlechip controller (6) and straight Stream reverse circuit (2) connects and overturning instruction is transmitted to direct current reverse circuit (2) to control the overturning of current direction.

2. crack propagation measuring system described in accordance with the claim 1, it is characterised in that: the isolation circuit (8) includes two Model is the optocoupler 1 and optocoupler 2 of PC817, No. 1 pin of the optocoupler 1 and access the end VCC (15) connection of circuit, No. 2 draw Foot is connect with the I/O mouth of singlechip controller (6), No. 3 pins are connect with the end VCC of singlechip controller (6), No. 4 pins with The end VCC of constant-current source (1) connects, No. 1 pin of the optocoupler 2 and the connection of VCC (15) end, No. 2 pins and singlechip controller (6) I/O mouth connection, No. 3 pins connect with the end GND of singlechip controller (6), the end GND of No. 4 pins and constant-current source (1) Connection.

3. crack propagation measuring system according to claim 2, it is characterised in that: the electric current connecting line (10) is by electric current Output lead (10-1) and electric current input lead (10-2) composition, the voltage connecting wire (11) is made of two conducting wires, described Direct current reverse circuit (2) includes solid-state relay SSR1, solid-state relay SSR2, solid-state relay SSR3, solid-state relay The transistor array of SSR4 and model ULN2003A, No. 9 pins of the transistor array access external 5V battery (14), No. 1 pin and No. 2 pins are connect with the instruction output end of singlechip controller (6), No. 15 pins of the transistor array It is all connected with No. 4 pins of solid-state relay SSR2 and No. 4 pins of solid-state relay SSR4, No. 16 pins and solid-state relay No. 4 pins of SSR1 and No. 4 pins of solid-state relay SSR3 are all connected with, No. 3 pins, the solid-states of the solid-state relay SSR1 No. 3 pins of No. 3 pins of relay SSR2, No. 3 pins of solid-state relay SSR3 and solid-state relay SSR4 access outer No. 2 pins of the 5V battery (14) connect, No. 2 pins of the solid-state relay SSR1 and solid-state relay SSR2 are and constant-current source (1) electric current cathode output end connection, No. 1 pin of the solid-state relay SSR3 and No. 1 pin of solid-state relay SSR4 It is connect with the electric current negative input of constant-current source (1), No. 1 pin and solid-state relay SSR4 of the solid-state relay SSR1 No. 2 pins connect with electric current output lead (10-1), No. 1 pin and solid-state relay of the solid-state relay SSR2 No. 2 pins of SSR3 are connect with electric current input lead (10-2).

4. crack propagation measuring system described in accordance with the claim 3, it is characterised in that: the electric current output lead (10-1) with The pad of sample (9) is measured to the distance of measurement sample (9) crackle, electric current input lead (10-2) and is measured sample (9) The distance of pad to measurement sample (9) crackle is all larger than the conducting wire of voltage connecting wire (11) and the pad of measurement sample (9) To the distance of measurement sample (9) crackle.

5. crack propagation measuring system according to claim 1 or 2, it is characterised in that: the constant-current source (1) is for model The programmable power supply of ZXY-6005S.

6. a kind of method for carrying out crack propagation measurement using system as claimed in claim 4, which is characterized in that this method includes Following steps:

Step 1: the power switch of crack propagation measuring system is opened, by electric current output lead (10-1) and electric current input lead (10-2) spot welding is connected to the crack surface two sides for measuring sample (9) respectively, and by voltage connecting wire (11), spot welding is connected to measurement examination respectively The crackle two sides of sample (9)；

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source (1), host computer are arranged in host computer (7) (7) setting Constant Direct Current current value order is transmitted to the number of constant-current source (1) by the data sending terminal of singlechip controller (6) According to receiving end, constant-current source (1) exports the Constant Direct Current electric current of host computer (7) setting, and constant dc is streamed to direct current overturning Circuit (2), direct current reverse circuit (2) do not stop to overturn Constant Direct Current electric current direction under the control of singlechip controller (6), not stop Constant dc circulation overcurrent output lead (10-1) of overturning is transmitted in measurement sample (9), and defeated from measurement sample (9) Direct current reverse circuit (2) are flow to through overcurrent input lead (10-2) after out；

Step 3: amplifier module (5) receives the measurement voltage signal of voltage connecting wire (11) transmission and believes the voltage of acquisition Number amplification, and the voltage signal of amplification is transmitted in singlechip controller (6) by amplifier module (5), singlechip controller (6) will Received voltage analog signal is converted into digital signal and carries out analytical calculation, and singlechip controller (6) simultaneously will be after analytical calculation Data be uploaded to host computer (7), operator can be checked in host computer (7) measurement sample (9) crack extending length data,

The analytical calculation formula of singlechip controller (6) are as follows:

A=15.153*u²+83.408u+3.2361

Wherein, a is the crack extending length for measuring sample (9) and unit is mm, and u is the voltage signal data for measuring sample (9) And unit is μ V；

The crack propagation DATA REASONING of measurement sample (9) finishes.

7. the verifying attachment that the crack propagation accuracy of measurement of measuring system described in a kind of pair of claim 4 is tested, special Sign is: including being fixed with the fixinig plate crack length change system (3) of multiple test samples and surveying for control test sample Measure the single-chip microcontroller and relay group control module (4) of order, the single-chip microcontroller and relay group control module (4) and fixed leafing Line length change system (3) connection and the test sample for being used to select to need output voltage signal, the electric current output lead (10-1) and electric current input lead (10-2) connect with the test sample in fixinig plate crack length change system (3) and straight Current signal after stream reverse circuit (2) overturning is transmitted separately to the test sample in fixinig plate crack length change system (3) Interior, the single-chip microcontroller connect with voltage connecting wire (11) with the output end of relay group control module (4) and by test sample Voltage signal is transmitted to amplifier module (5).

8. verifying attachment according to claim 7, it is characterised in that: fixinig plate crack length change system (3) packet Ten test samples and five connecting terminals are included, five connecting terminals are four connecting terminals, five terminals Son is respectively connecting terminal 1, connecting terminal 2, connecting terminal 3, connecting terminal 4 and connecting terminal 5, and described ten test samples are equal For 304 steel test samples, the crack extending length of described ten test samples it is known and according to crack length from short to long according to The crack length of secondary arrangement, the test sample 1 is most short and the crack length longest of test sample 10, the electric current output lead The other end of (10-1) is connect with the crack surface side spot welding of test sample 1, the crack surface other side of the test sample 1 and inspection Test the crack surface side conducting wire spot welding connection of sample 2, the crack surface other side of the test sample 2 and splitting for test sample 3 Line face side is connected with conducting wire spot welding, and the crack surface side of the crack surface other side of the test sample 3 and test sample 4 is with leading Line spot welding connection, the crack surface other side of the test sample 4 are connect with the crack surface side of test sample 5 with conducting wire spot welding, The crack surface other side of the test sample 5 is connect with the crack surface side of test sample 6 with conducting wire spot welding, the test sample The 6 crack surface other side is connect with the crack surface side of test sample 7 with conducting wire spot welding, and the crack surface of the test sample 7 is another Side is connect with the crack surface side of test sample 8 with conducting wire spot welding, and the crack surface other side of the test sample 8 and inspection try The crack surface side of sample 9 is connected with conducting wire spot welding, the crack surface other side of the test sample 9 and the crack surface of test sample 10 Side is connected with conducting wire spot welding, and the crack surface other side of the test sample 10 is connect with electric current input lead (10-2)；

The crackle side of the test sample 1 is connect with the interface of front end 1 of connecting terminal 1, and the crackle of the test sample 1 is another Side is connect with the interface of front end 2 of connecting terminal 1, the crackle side of the test sample 2 and the front end 1 of connecting terminal 2 Interface connection, the crackle other side of the test sample 2 are connect with the interface of front end 2 of connecting terminal 2, the test sample 3 Crackle side connect with the interface of front end 1 of connecting terminal 3, the crackle other side of the test sample 3 and connecting terminal 3 The interface connection of front end 2, the crackle side of the test sample 4 are connect with the interface of front end 1 of connecting terminal 4, the inspection The crackle other side of sample 4 is connect with the interface of front end 2 of connecting terminal 4, the crackle side of the test sample 5 and terminals The interface connection of front end 1 of son 5, the crackle other side of the test sample 5 are connect with the interface of front end 2 of connecting terminal 5, institute The crackle side for stating test sample 6 is connect with the interface of rear end 4 of connecting terminal 5, the crackle other side of the test sample 6 with The interface connection of rear end 3 of connecting terminal 5, the crackle side of the test sample 7 and the interface of rear end 4 of connecting terminal 4 connect It connects, the crackle other side of the test sample 7 is connect with the interface of rear end 3 of connecting terminal 4, the crackle of the test sample 8 Side is connect with the interface of rear end 4 of connecting terminal 3, the crackle other side of the test sample 8 and the rear end 3 of connecting terminal 3 The connection of number interface, the crackle side of the test sample 9 are connect with the interface of rear end 4 of connecting terminal 2, the test sample 9 The crackle other side connect with the interface of rear end 3 of connecting terminal 2, the crackle side of the test sample 10 and connecting terminal 1 Rear end No. 4 interfaces connection, the crackle other side of the test sample 10 is connect with the interface of rear end 3 of connecting terminal 1.

9. verifying attachment according to claim 8, it is characterised in that: the single motor and relay group control module (4) By the singlechip chip of No. 8 relay group A, No. 8 relay group B, No. 8 relay group C and a model STM32F103C8T6 Composition, the IN1 pin of No. 8 relay A to IN8 pin successively respectively with the A6 pin of singlechip chip, No. A12 Pin, A11 pin, A8 pin, B15 pin, B14 pin, B13 pin are connected with B12 pin, 8 tunnel The IN1 pin of relay B successively draws with the A5 pin of singlechip chip, A4 pin, No. B5 respectively to IN8 pin Foot, B6 pin, B7 pin, B8 pin, B11 pin are connected with B9 pin, and No. IN1 of No. 8 relay C is drawn Foot is successively connect with the B10 pin of singlechip chip, B1 pin, B0 pin and A7 pin respectively to IN4 pin, The end VCC of No. 8 relay group A, the end VCC of No. 8 relay group B, No. 8 relay group C the end VCC and singlechip chip 5v pin connection, the end GND of No. 8 relay group A, the end GND of No. 8 relay group B, No. 8 relay group C the end GND It is connect with the end GND of singlechip chip, the singlechip chip is connect with the input terminal of amplifier module (5)；

The interface of front end 3 of the connecting terminal 1 connect with No. 1 pin of the 10B of No. 8 relay group C, the interface of front end 4 and 8 No. 1 pin of the 10A of road relay group C connects, the interface of rear end 1 is connect with No. 1 pin of the 1A of No. 8 relay group A, rear end No. 2 interfaces are connect with No. 1 pin of the 1B of No. 8 relay group A；The interface of front end 3 and No. 8 relays of the connecting terminal 2 Group C 9B No. 1 pin connection, the interface of front end 4 connect with No. 1 pin of the 9A of No. 8 relay group C, the interface of rear end 1 and No. 1 pin connection of the 2A of No. 8 relay group A, the interface of rear end 2 are connect with No. 1 pin of the 2B of No. 8 relay group A；It is described The interface of front end 3 of connecting terminal 3 connect with No. 1 pin of the 8B relay of No. 8 relay group B, the interface of front end 4 and 8 tunnels No. 1 pin of the 8A of relay group B connects, the interface of rear end 1 is connect with No. 1 pin of the 3A of No. 8 relay group A, rear end 2 Interface is connect with No. 1 pin of the 3B of No. 8 relay group A；The interface of front end 3 of the connecting terminal 4 and No. 8 relay group B No. 1 pin connection of 7B, the interface of front end 4 connect with No. 1 pin of the 7A of No. 8 relay group B, the interface of rear end 1 and 8 tunnels No. 1 pin connection of the 4A of relay group A, the interface of rear end 2 are connect with No. 1 pin of the 4B of No. 8 relay group A；It is described to connect The interface of front end 3 of line terminals 5 connect with No. 1 pin of the 6B of No. 8 relay group B, the interface of front end 4 and No. 8 relay group B No. 1 pin connection of 6A, the interface of rear end 1 connect with No. 1 pin of the 5A of No. 8 relay group B, the interface of rear end 2 and 8 tunnels No. 1 pin of the 5B of relay group B connects；No. 2 pins of the 1A of No. 8 relay group A, No. 8 relay group A 2A 2 Number pin, No. 2 pins of the 3A of No. 8 relay group A, No. 2 pins of the 4A of No. 8 relay group A, No. 8 relay group B 5A No. 2 pins, No. 2 pins of the 6A of No. 8 relay group B, No. 2 pins of the 7A of No. 8 relay group B, No. 8 relay group B 8A No. 2 pins, No. 8 relay group C No. 2 pins of 9A and No. 2 pins of 10A of No. 8 relay group C link together, institute State No. 2 pins of the 1B of No. 8 relay group A, No. 2 pins of the 2B of No. 8 relay group A, No. 8 relay group A No. 2 of 3B draw Foot, No. 2 pins of the 4B of No. 8 relay group A, No. 2 pins of the 5B of No. 8 relay group B, No. 2 of 6B of No. 8 relay group B Pin, No. 2 pins of the 7B of No. 8 relay group B, No. 2 pins of the 8B of No. 8 relay group B, No. 8 relay group C 9B 2 No. 2 pins of the 10B of number pin and No. 8 relay group C link together.

10. a kind of tested the method for measuring system On Crack Propagation accuracy of measurement using device as claimed in claim 9, It is characterized in that, method includes the following steps:

Step 1: the power switch of the verifying attachment of crack propagation measuring system and crack propagation measuring system is opened；

Step 2: the output Constant Direct Current current value and output voltage values of constant-current source (1), host computer are arranged in host computer (7) (7) setting Constant Direct Current current value order is connect into end by the data transmission of singlechip controller (6) and is transmitted to constant-current source (1) Data receiver connects end, and constant-current source (1) exports the Constant Direct Current electric current of host computer (7) setting, and constant dc is streamed to direct current Reverse circuit (2), direct current reverse circuit (2) do not stop reset current direction under the control of singlechip controller (6), do not stop to overturn Constant dc circulation overcurrent output lead (10-1) be transmitted to ten of fixinig plate crack length change system (3) inspections It in sample, and is flowed back in direct current reverse circuit (2) through overcurrent input lead (10-2), ten test samples are that known crackle is long The crack length of the test sample of degree and ten test samples is unequal；

Step 3: single-chip microcontroller and the singlechip chip of relay group control module (4) are according to the finger for connecting examination 1 circuit of test sample It enables and controls corresponding No. 8 relay group for the voltage signal circuit connection of test sample 1 and voltage signal is transmitted to amplifier mould Block (5), amplifier module (5) is interior by voltage signal transmission singlechip controller (6) after amplifying the voltage signal of acquisition, single-chip microcontroller Controller (6) converts digital signal for received analog voltage signal and carries out analytical calculation, and singlechip controller (6) will divide Data after analysis calculates are uploaded to host computer (7), and operator can check that the crack propagation of test sample 1 is long in host computer (7) Degree evidence,

The analytical calculation formula of singlechip controller (6) are as follows:

A=15.153*u²+83.408u+3.2361

Wherein, a is the crack extending length of test sample and unit is mm, and u is the voltage signal data of the test sample of measurement And unit is μ V；

Step 5: by the test sample 1 of acquisition to test sample 10 data respectively with the known crackle of corresponding test sample Data are compared, and examine crackle by the relationship between the test data and known crack data of ten test samples of comparison Extend the accuracy of measurement of measuring system.