CN1420345A - Ultrasonic bolt fastening force measuring devcie - Google Patents

Abstract

An ultrasonic tester of the fastening force for screw bolt is composed of longitudinal wave transducer connected serially to ultrasonic emitter, longitudinal wave receiver and amplifer, transverse wave transducer connected serially to ultrasonic emitter, transverse wave receiver and amplifier, displacement sensor connected serially with thickness measuring circuit, A/D converter and DSP, temp sensor connected serially to temp measuring circuit, A/D converter and DSP, main oscillator, time pulse generator, and ROM. Its feature is use of sono-elasticity principle.

Description

Ultrasonic bolt fastening force proving installation

Technical field

The present invention relates to the metering of power or stress, is a kind of ultrasonic bolt fastening force proving installation.

Background technology

Construction steel structure with its cost be lower than xoncrete structure, effectively usable floor area is higher than xoncrete structure, pollution is less than xoncrete structure, anti-seismic performance is good, and China's output of steel leapt to the first in the world, and national policy is encouraged in the building how all multifactor and developed rapidly with steel etc.Regional steel structure of housing proportion such as Japan and Korea S., West Europe is up to 20～50%, and China is at present still less than 1%, so steel building also has very big development space in China.

A large amount of high-strength bolts that use connect in the steel construction.Therefore, its construction quality directly influences construction engineering quality and safe in utilization.Therefore, the fastening force of high-strength bolt must be controlled within the limits prescribed, and is too small no doubt not all right, excessive more harmful.Because the material of high-strength bolt has certain fragility, the excessive bolt of fastening force might rupture under loading at first, thereby weakens the bearing capacity of this node, just may bring out structural instability when serious, causes security incident.For this reason, nation-building portion, State General Administration for Quality Supervision unite and have issued " GB 50205-2001 code for acceptance of construction quality of steel structures ", this have been done specified in more detail.Also have other relevant criterion such as GB/T 1228～1231 in addition, standards such as GB/T 3632～3633 are supporting with it, it serves to show the importance of this thing.

The size of high-strength bolt fastening force is directly to measure when practice of construction, but control by the moment of torsion that tights a bolt.Because aspects such as workmen's quality, construction appliance and construction management owe to twist and super stubborn phenomenon is difficult to avoid fully.Present postmortem method is that the sampling part withdraws from heavily stubborn.Not only time-consuming bothersome, and selective examination face is very little.This still there is not ripe way abroad yet.

Summary of the invention

The purpose of this invention is to provide a kind of ultrasonic bolt fastening force proving installation, it realizes the Non-Destructive Testing of bolted power by ultrasound wave.

The technical solution used in the present invention comprises:

1) be installed in compressional wave transducer, the shear wave transducer of bolt end face respectively, the compressional wave transducer connects ultrasonic transmit circuit respectively and connects amplifier through the compressional wave receiving circuit, and shear wave transducer connects ultrasonic transmit circuit respectively and connects amplifier through the shear wave receiving circuit;

2) displacement transducer that is installed in clamped workpiece both ends of the surface connects the DSP central processing unit through thickness measuring circuit, an A/D analog to digital conversion circuit;

3) temperature sensor that is installed in nut end face connects the DSP central processing unit through temperature measurement circuit, the 2nd A/D analog to digital conversion circuit;

4) master oscillator connects the ultrasound emission circuit diagram respectively and connects amplifier through logical circuit;

5) the main pulse circuit connects the DSP central processing unit through the progressive mean circuit time;

6) read only memory ROM that is used for the storage medium coefficient is articulated in the DSP central processing unit.

The ultrasound emission circuit comprises that trigger pulse produces circuit and transponder pulse produces circuit, and trigger pulse produces circuit and realizes that by two 555 timers first 555 timer constitutes the multivibrator of an EDM Generator of Adjustable Duty Ratio; Second 555 timer constitutes a square-wave generator; Emission voltage is added on the switch transistor T R1 collector switch transistor T R1 grounded emitter by resistance R 8; The mode that the ultrasonic transducer transponder pulse adopts capacitance energy storage and inductive energy storage to combine, it is made up of switch transistor T R1, storage capacitor C3, energy storage inductor L etc.;

Compressional wave reception and amplifier and shear wave receive and amplifier is two circuit of identical parameters, comprise transducer and three grades of amplifications: preceding two-stage adopts high speed and precision amplifier LM318; The third level is adopted operational amplifier LF353;

The thickness measuring circuit comprises sinusoidal wave generation circuit and peak extraction circuit, after the digitizing of A/D analog to digital conversion circuit with DSP central processing unit interface;

Temperature measurement circuit is converted into voltage output by operational amplifier 4558 with electric current output, is convenient to after the digitizing of A/D analog to digital conversion circuit and DSP central processing unit interface;

Master oscillator comprises three digital not gates and RC circuit;

The time main pulse connect with the circuit that two not gates are formed by crystal oscillator two electric capacity in parallel and two resistance and export the progressive mean circuit to by another not gate;

Logical circuit comprises echo identification circuit and zero passage extraction circuit, is made up of high-speed comparator LM360 and JK flip-flop 74L573 respectively;

The progressive mean circuit can be formed minimum Single Chip Microcomputer (SCM) system by the MCS-51 series monolithic and realize.

The present invention compares with background technology, and the useful effect that has is: adopt the acoustic elasticity principle, determine the fastening force of bolt by measuring ultrasound wave velocity of propagation in bolt.The axial stress that this proving installation can be widely used in high-strength bolt on the steel construction detects, and directly measuring on the attachment bolt, can not cause any destruction to coupling member, can realize real Non-Destructive Testing.Be applicable to 8.8 grades of detections, can be applicable to the accurate control of bolt pretightening and the monitoring of working bolt stress with 10.9 grade high-strength bolt axial stresses.Measuring accuracy can reach 8%, is less than 3 minutes detection time.The occasion that can be widely used in tight Bolt Connection.

Description of drawings

Fig. 1 is that the vertical shear wave technique of the present invention is surveyed fastening bolt axial stress size agreement figure;

Fig. 2 is a structured flowchart of the present invention;

Fig. 3 is ultrasound emission circuit theory diagrams of the present invention;

Fig. 4 is ultrasonic reception of the present invention, amplifying circuit schematic diagram;

Fig. 5 is a temperature measurement circuit schematic diagram of the present invention;

Fig. 6 is thickness measuring circuit theory diagrams of the present invention;

Fig. 7 is a master oscillator schematic diagram of the present invention;

Main pulse circuit theory diagrams when Fig. 8 is of the present invention;

Fig. 9 is a logical circuit principle of the present invention.

Embodiment

1, the theory of testing of the present invention basis

When bolt was not subjected to stress, the velocity of sound propagated therein of ripple was in length and breadth: $C_{l0}=\sqrt{(\mathrm{\λ}+2\mathrm{\μ}){\mathrm{\ρ}}_0}$ $C_{t0}=\sqrt{\mathrm{\μ}/{\mathrm{\ρ}}_0}----\left(1\right)$ In the following formula: C _L0, C _T0---be respectively the velocity of sound that longitudinal and transverse ripple is propagated in solid material;

ρ ₀---the density of material;

λ, μ---Lame's constant.

And according to nonlinear elastic theory and nonlinear acoustics, when the isotropic solid material is subjected to a certain direction stress and ripple is with stress direction when consistent in length and breadth, the pass of the velocity of sound and stress is:

(V _l0-C _l0)/C _l0＝-K _L·T

(V _T0-C _T0)/C _T0=-K _TIn T (2) following formula: K _L, K _T---only relevant coefficient with material;

V _L0, V _T0---be subjected to the longitudinal and transverse wave sound speed behind the stress;

C _L0, C _T0---the stressed preceding velocity of sound;

T---stress.

If temperature was not t when bolt was subjected to stress ₀℃, the temperature expansion coefficient of bolt is β, and then bolt is when temperature is t ℃, and the sound propagated in bolt of ripple the time is respectively in length and breadth:

S _l0＝2L ₀[1+β(t-t ₀)]/V _l(t)

S _t0＝2L ₀[1+β(t-t ₀)]/V _t(t) (3)

Temperature to the influence of the velocity of sound is:

V _l(t)＝C _l0(1-α _lΔt)

V _t(t)=C _T0(1-α _tΔ t) (4) wherein: Δ t=t-to, V _l(t), V _t(t) be respectively that longitudinal and transverse ripple is not subjected to stress and the velocity of sound of temperature when being t ℃,

L。For bolt is t in temperature ₀℃ the time length, β is a temperature expansion coefficient, C _L0, C _T0Respectively

For ripple in length and breadth is t not being subjected to stress and temperature ₀℃ the time the velocity of sound, α _lAnd α _tBe respectively wave sound speed in length and breadth

Temperature variant coefficient of sound velocity.So:

S _l0＝2L ₀(1+βΔt)/[C _l0(1-α _lΔt)]

S _t0＝2L ₀(1+βΔt)/[C _t0(1-α _tΔt)]

If horizontal compressional wave is S when not being subjected to stress _T0To S _L0Ratio is:

x ₀＝S _t0/S _l0＝[C _l0(1-α _lΔt)]/[C _t0(1-α _tΔt)]

And α _lAnd α _tBe about 10 ^-4The order of magnitude is a constant relevant with material.So when Δ t＜10 ³During ℃ order of magnitude, α _lα _tΔ t＜10 ^-5, get first approximation and get:

Following formula shows when Δ t＜10 ³The time, x ₀Be approximately a straight line with Δ t, and slope is (α _t-α _l) C _L0/ C _T0

If bolt is subjected to tension T, under the temperature t ℃ situation, the sound propagated in bolt of ripple the time is S in length and breadth _lAnd S _t,

x ₀=S _T0/ S _L0≈ C _L0(1-α _lΔ t-α _tΔ t)/C _T0The sound of propagating in the bolt time is part of the force and sum when not stressing part sound, considers the elongation to bolt of temperature and stress, and note utilizing formula (4) and Fig. 1 then have $S_l=\frac{2\mathrm{\Δl}[1+\mathrm{\β}(t-t_0)]}{V_l\left(t\right)}+\frac{{2r}^{\′}[1+\mathrm{\β}(t-t_0)]+2r^{\′}T/E}{V_l(T,t)}$ $=\frac{2\mathrm{\Δl}[1+\mathrm{\β}(t-t_0)]}{C_{l0}[1-{\mathrm{\α}}_l(t-t_0)]}+\frac{{2r}^{\′}[1+\mathrm{\β}(t-t_0)]+{2r}^{\′}T/E}{C_{l0}[1-{\mathrm{\α}}_l(t-t_0)](1-K_{L}T)}$ $=S_{l0}+\frac{{2r}^{\′}(1+\mathrm{\β\Δt})+{2r}^{\′}T/E-{2r}^{\′}(1+\mathrm{\β\Δt})(1-K_{L}T)}{C_{l0}(1-{\mathrm{\α}}_l\mathrm{\Δt})(1-K_{L}T)}$

V in the following formula _l(t), V _l(T, t) being respectively compressional wave, not to be subjected to stress and temperature be t ℃ and the velocity of sound when being subjected to stress T and temperature to be t ℃; E is a young modulus, r '=r+r ₁+ r ₂Be effective clamping distance, promptly bolt is subjected to stress length (see figure 1), and r is a clamping distance in two nuts, (r ₁+ r ₂) be that the stressed length of two nut inner bolts claims clamping distance; K _LBy the constant of material decision, T is a stress for only; Δ l=L ₀-r ' is not subjected to stress length for bolt, 2 Δ l β (t-t ₀) for bolt does not stress length by the sound path that temperature variation increased, 2r ' T/E be bolt strained length by the sound path that STRESS VARIATION increased, 2r ' β (t-t ₀) be that bolt strained length is by the added sound path of temperature variation.Shear wave situation all fours.Abbreviation, the sound propagated in bolt of ripple the time is in length and breadth: $S_l=S_{l0}+\frac{{2r}^{\′}(1+\mathrm{\β\Δt})K_{L}T+{2r}^{\′}T/E}{C_{l0}(1-{\mathrm{\α}}_l\mathrm{\Δt})(1-K_{L}T)}$ $S_t=S_{t0}+\frac{{2r}^{\′}(1+\mathrm{\β\Δt})K_{T}T+{2r}^{\′}T/E}{C_{t0}(1-{\mathrm{\α}}_t\mathrm{\Δt})(1-K_{T}T)}$ Following formula further abbreviation is: $T=\frac{S_l{x}_0-S_t}{(S_l{x}_0-S_t)(K_L+K_T)+\frac{{2r}^{\′}(1+\mathrm{\β\Δt})(K_L-K_T)}{C_{t0}(1-{\mathrm{\α}}_t\mathrm{\Δt})}}$

By document [1] as can be known, K _LBe about 10 ^-5/ MPa=10 ^-11m ²/ N, K _TBe about 10 ^-12m ²/ N the order of magnitude.(the K of T＜250MPa, so T generally speaking _T+ K _L)＜＜1, following formula can further turn to: $T=\frac{C_{t0}(1-{\mathrm{\α}}_t\mathrm{\Δt})(S_l{x}_0-S_t)}{{2r}^{\′}(1+\mathrm{\β\Δt})(K_L-K_T)}....\left(5\right)$

Definition:

K(r)＝C _t0/[2r′(K _L-K _T)]

K(t)＝(1-α _tΔt)/(1+βΔt)

Then:

T=K (r) K (t) (S _lx ₀-S _t) (6) K (r) is only relevant with material and clamping distance and a temperature and the irrelevant coefficient of stress, K (t) is only relevant with a material and temperature coefficient that has nothing to do with stress, x ₀Be the horizontal stroke of bolt when unstressed, the ratio of longitudinal wave velocity, its value is relevant with temperature and material and irrelevant with stress.Therefore K (r), K (t), x ₀All can before actual measurement, measure its respective bolt material value and be stored in the data-carrier store.When temperature variation little (less than 100 ℃), during the wave sound in length and breadth that records when being subjected to stress, can go out bolt stress by formula (6) approximate treatment according to bolt.

By the bolt of different materials being measured it in length and breadth during wave sound under stress-free conditions, with computer data acquisition and describe curve, different materials has different slopes, i.e. x ₀=S _T0/ S _L0For same material x ₀Linear function for temperature.X with various materials ₀Fit to linear relation x with temperature t ₀(t) be stored in the ROM (read-only memory).

R '=r+r in the formula (5) ₁+ r ₂Being that bolt should stressed length be not easy directly to measure, is to measure (r easily but r is a clamping distance ₁+ r ₂) be bolt part of the force in the nut district, can't directly measure.For obtaining K (r), make Δ S=S _lx ₀-S _tSo: $\frac{1}{K\left(r\right)}=\frac{K\left(t\right)\mathrm{\&Delta;S}}{T}=\frac{2(K_L-K_T)}{C_{t0}}(r+{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="A0215447400123.png,A0215447400143.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+r_2)......\left(7\right)$

Wherein: K (t) is the irrelevant constant of and stress relevant with material and temperature only, can directly calculate by material characteristic parameter and temperature;

Be only relevant constant with material.Therefore measure same temperature, stress, a series of under the different clamping distance r Value is carried out fitting a straight line with this value to r and is obtained (r ₁+ r ₂), can obtain the value of K (r).

K (r), K (t) and x with various bolt materials ₀(t) value is all measured and is stored in the ROM (read-only memory).When surveying fastening bolt stress, extract corresponding K (r), K (t) and x according to the bolt temperature that known bolt material and temperature measurement circuit obtain ₀(t) value when recording the longitudinal and transverse wave sound when being subjected to stress simultaneously and clamping distance, just can calculate axial stress in the fastening bolt according to formula (6).

2, apparatus structure and principle of work

As shown in Figure 2, be structured flowchart of the present invention, it comprises:

1) is installed in compressional wave transducer 7, the shear wave transducer 8 of bolt end face respectively, compressional wave transducer 7 connects ultrasonic transmit circuit 10 respectively and connects amplifier 13 through compressional wave receiving circuit 9, and shear wave transducer 8 connects ultrasonic transmit circuit 10 respectively and connects amplifier 13 through shear wave receiving circuit 16;

2) displacement transducer 1 that is installed in clamped workpiece both ends of the surface connects DSP central processing unit 17 through thickness measuring circuit 3, an A/D analog to digital conversion circuit 4;

3) temperature sensor 2 that is installed in nut end face connects DSP central processing unit 17 through temperature measurement circuit 5, the 2nd A/D analog to digital conversion circuit 6;

4) master oscillator 11 connects ultrasound emission circuit 10 respectively and connects amplifier 13 through logical circuit 12;

5) main pulse circuit 14 connects DSP central processing unit 17 through progressive mean circuit 15 time;

6) read only memory ROM 18, keyboard 19, display 21 and the storer 20 that is used for the storage medium coefficient is articulated in DSP central processing unit 17.

As shown in Figure 3, ultrasound emission circuit 10 comprises that trigger pulse produces circuit 10.1 and transponder pulse produces circuit 10.2; By the break-make of master oscillator 11 gauge tap pipe TR, produce circuit 10.1 to trigger pulse power supply VCC is provided.When producing, master oscillator 11 transmits, switch transistor T R conducting, and trigger pulse produces circuit 10.1 work, does not work otherwise trigger pulse produces circuit 10.1.Produce the break-make that circuit produces trigger pulse gauge tap pipe TR1 by trigger pulse, when switch transistor T R1 conducting, transponder pulse produces circuit working, and the transponder pulse of generation is added to and makes its emission ultrasound wave on the transducer; When switch transistor T R1 ended, transducer stopped emission; Trigger pulse produces circuit and realizes that by two 555 timers first 555 timer constitutes the multivibrator of an EDM Generator of Adjustable Duty Ratio; Second 555 timer constitutes a square-wave generator, and 3 pin produce square wave, deliver to switch transistor T R1 base stage by pull-up resistor R7, the break-make of gauge tap pipe TR1.The cycle of master pulse has determined the cycle of ultrasound wave repeat its transmission.Master pulse is terminated at 4 ends (internal reset end) of second timer 555, and this makes when the high level of master pulse, and square-wave generator work produces square-wave pulse; And master pulse is when being low level, and square-wave generator resets.Can change the number of trigger pulse easily by standardsizing rheostat R2, and then control exomonental number.The mode that the ultrasonic transducer transponder pulse adopts capacitance energy storage and inductive energy storage to combine, it is made up of switch transistor T R1, storage capacitor C3, energy storage inductor L etc.Before trigger pulse arrived, switch transistor T R1 ended, and emission voltage charges to capacitor C 3 by resistance R 8; When trigger pulse arrives, switch transistor T R1 conducting, capacitor C 3 is discharged to transducer by switch transistor T R1.Because the conducting resistance of switch transistor T R1 is little, fill on the capacitor C 3 voltage almost all be added on the transducer, make it to obtain energy and produce ultrasonic radiation.

As shown in Figure 4, compressional wave reception 9 and amplifier 13 and shear wave reception 16 and amplifier 13 are two circuit of identical parameters, and comprise 7,8 and three grades of amplifications of transducer: preceding two-stage kind is amplified 100 times, adopts high speed and precision amplifier LM318; Ultrasonic receiving transducer signal is sent into high speed and precision amplifier LM318 in-phase end in the first order amplifying circuit, end of oppisite phase is by resistance R 10 ground connection, realize negative feedback by resistance R 11 simultaneously, output is sent into second level high speed and precision amplifier LM318 in-phase end by capacitor C 7 and resistance R 12, end of oppisite phase is realized positive feedback by resistance R 14 simultaneously by resistance R 13 ground connection.Circuit bandwidth 15MHz when enlargement factor is 100 times, can fully meet the demands; The third level is adopted operational amplifier LF353, realizes positive feedback by resistance R 17, and all the other connections are identical with second level amplifying circuit, and output is delivered to logical circuit by capacitor C 19 and resistance R 18.

As shown in Figure 5, temperature measurement circuit 5 is converted into voltage output by operational amplifier 4558 with electric current output, and temperature sensor 2 can adopt semiconductor temperature sensor AD590.AD590 is actually a current source that is directly proportional with absolute temperature, and its acceptable operating voltage can be from 4-30V, and the sensed temperature scope is-55-+150 ℃.It has extraordinary linear output, and its output current is directly proportional with temperature, and its its output current in the time of 0 ℃ is 273.2uA, so be 373.2uA in the time of 100 ℃.Adopt operational amplifier 4558 that electric current output is converted into voltage output so that after the ADC0804 digitizing with the dsp processor interface.

As shown in Figure 6, thickness measuring circuit 3 comprises sinusoidal wave generation circuit 3.1 and peak extraction circuit 3.2, after 4 digitizings of A/D analog to digital conversion circuit with DSP central processing unit 17 interfaces.Adopt differential displacement sensor to carry out the gripping layer thickness measure, precision can reach 0.1mm, and the A/D analog to digital conversion circuit can be selected the ADC0804 chip for use.

As shown in Figure 7, master oscillator 11 comprises that three digital not gates connect with the RC circuit; This is the foolproof circuit of a kind of structure, is easy to select the frequency of suitable R, this oscillator of C parameter adjustment.

As shown in Figure 8, the circuit that main pulse circuit 14 is made up of crystal oscillator two electric capacity in parallel and two resistance Sheffer stroke gates the time is connected and is exported progressive mean circuit 15 to by not gate; This also is the circuit that elements such as a kind of easy gate circuit and crystal oscillator are formed, and this pulsing circuit is operated in the oscillatory regime of crystal oscillator fundamental frequency.

As shown in Figure 9, logical circuit 12 comprises echo identification circuit 12.1 and zero passage extraction circuit 12.2 two parts, is made up of high-speed comparator LM360 and JK flip-flop 74L573 respectively.Logical circuit adopts the zero passage detection technology, and the upset comparative level of high-speed comparator LM360AC is arranged on away from the impulse ultrasound cycle signal zero-cross point, has strengthened the antijamming capability of circuit so greatly.

When using this proving installation to carry out the measurement of bolted power, at first mechanical grinding is carried out in the end of threaded section of bolt, reach and be coated with couplant after certain smooth finish requires, with anchor clamps ultrasonic longitudinal and transverse wave transducer probe is pressed, simultaneously displacement transducer is clipped in clamped workpiece both ends of the surface, and on nut, presses temperature sensor.Transducer, displacement transducer, temperature sensor and anchor clamps are made one, make instrument more portable reliable.Keyboard 19 input bolt materials, the emission ultrasound wave can show bolted stress value this moment, and can be stored in the storer 20 on display 21.This ultrasonic bolt fastening force proving installation is easy to operate, is no more than 3 minutes detection time.Mounting means and principle of work such as Fig. 2.

Specific embodiment:

For M30 * 210,10.9 grade construction steel structure high-strength bolt, material is 20MnTiB.At first mechanical grinding is carried out in the end of threaded section of bolt, reach and be coated with couplant after certain smooth finish requires, installation testing device various kinds of sensors, keyboard input bolt material is 20MnTiB, the emission ultrasound wave when obtaining longitudinal and transverse ripple propagation sound by the sound transit-time measurement circuit, records grip thickness by displacement transducer simultaneously, temperature sensor records the bolt temperature, delivers to the DSP central processing unit; The DSP central processing unit is by looking into material coefficient K (r), K (t) and the x that tables of data in the material coefficient read only memory ROM obtains 20MnTiB ₀Value, and utilize formula T=K (r) K (t) (S _lx ₀-S _t) calculate this moment bolt fastening stress.This stress value is shown by display, and be stored in the data-carrier store.

Claims (2)

1. ultrasonic bolt fastening force proving installation is characterized in that it comprises:

1) is installed in compressional wave transducer (7), the shear wave transducer (8) of bolt end face respectively, compressional wave transducer (7) connects ultrasonic transmit circuit (10) respectively and connects amplifier (13) through compressional wave receiving circuit (9), and shear wave transducer (8) connects ultrasonic transmit circuit (10) respectively and connects amplifier (13) through compressional wave receiving circuit (16);

2) displacement transducer (1) that is installed in clamped workpiece both ends of the surface respectively connects DSP central processing unit (17) through thickness measuring circuit (3), an A/D analog to digital conversion circuit (4);

3) temperature sensor (2) that is installed in nut end face connects DSP central processing unit (17) through temperature measurement circuit (5), the 2nd A/D analog to digital conversion circuit (6);

4) master oscillator (11) connects ultrasound emission circuit (10) respectively and connects amplifier (13) through logical circuit (12);

5) main pulse circuit (14) connects DSP central processing unit (17) through progressive mean circuit (15) time;

6) read only memory ROM (18) that is used for the storage medium coefficient is articulated in DSP central processing unit (17).

2. ultrasonic bolt fastening force proving installation according to claim 1 is characterized in that:

1) ultrasound emission circuit (10) comprises that trigger pulse produces circuit (10.1) and transponder pulse produces circuit (10.2), and trigger pulse produces circuit and realizes that by two 555 timers first 555 timer constitutes the multivibrator of an EDM Generator of Adjustable Duty Ratio; Second 555 timer constitutes a square-wave generator; Emission voltage is added on the switch transistor T R1 collector switch transistor T R1 grounded emitter by resistance R 8; The mode that the ultrasonic transducer transponder pulse adopts capacitance energy storage and inductive energy storage to combine, it is made up of switch transistor T R1, storage capacitor C3, energy storage inductor L etc.;

2) compressional wave reception (9) and amplifier (13) and shear wave reception (16) and amplifier (13) are two circuit of identical parameters, comprise transducer (7,8) and three grades of amplifications: preceding two-stage adopts high speed and precision amplifier LM318; The third level is adopted the LF353 operational amplifier;

3) thickness measuring circuit (3) comprises sinusoidal wave generation circuit (3.1) and peak extraction circuit (3.2), after MD analog to digital conversion circuit (4) digitizing with DSP central processing unit (17) interface;

4) temperature measurement circuit (5) is converted into voltage output by amplifier 4558 with electric current output, is convenient to after A/D analog to digital conversion circuit (6) digitizing and DSP central processing unit (17) interface;

5) master oscillator (11) comprises three digital not gates and RC circuit;

6) the main pulse time (14) is connected with the circuit that two not gates are formed by crystal oscillator two electric capacity in parallel and two resistance and is exported progressive mean circuit (15) to by another not gate;

7) logical circuit (12) comprises echo identification circuit (12.1) and zero passage extraction circuit (12.2), is made up of high-speed comparator LM360 and JK flip-flop 74L573 respectively;

8) progressive mean circuit (15) can be formed minimum Single Chip Microcomputer (SCM) system realization by the MCS-51 series monolithic.

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