CN87104955A - Tension testing instrument for steel wires - Google Patents

Tension testing instrument for steel wires Download PDF

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CN87104955A
CN87104955A CN87104955.4A CN87104955A CN87104955A CN 87104955 A CN87104955 A CN 87104955A CN 87104955 A CN87104955 A CN 87104955A CN 87104955 A CN87104955 A CN 87104955A
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steel wire
frequency
circuit
starting
sampling
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CN1006088B (en
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朱润枢
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ZHEJIANG PROV INST OF ARCHITECTURE
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Abstract

The present invention is a kind of new tension testing instrument for steel wires.
The present invention proposes a kind of new ergographic clamp system, starting of oscillation mechanism, have new full digital sampling hold circuit and calculating parameter translation circuit, and be common to whole prestress value scopes of cold-drawn low-carbon wire, low-alloy (in strong) steel wire and carbon element (high-strength) steel wire φ 3, φ 4, φ 5.At steel wire length overall 〉=2m, operating modes such as long-line pedestal, the outer stretch-draw of short-term mould or steel wire layered arrangement directly once show steel wire stretching force value, dynamometry error≤1.5%.

Description

The present invention is based on the dynamometry instrument of method of oscillatory frequency principle, and the starting of oscillation of instantaneous initiation steel wire measures fundamental vibration frequency in the process of its free vibration attenuation, calculates and demonstrate the suffered stretching force value of steel wire through this instrument.
This instrument is used for construction work or building prefabricated components is produced, and steel wire measures its stretching force value after stretch-draw and two ends anchoring.In the quality control and management of prestressed reinforced concrete construction, it is an important link that prestress value adheres to specification.
The domestic and international technology the most approaching with the present invention, the prestress detecting instrument of method of oscillatory frequency principle is seen documents 1,2,3.
Documents 1:A II-12 type frequency meter (Ч а с т о т н
Figure 87104955_IMG2
й и р и ó о р A II-12), С. И. Н О Г И Н, В. С. Г О Л О Б О р О Б К О, " Б Е Т О Н И Ж Е Л Е З О Б Е Т О Н ", and 1985, № 3, the 39-40 page or leaf.
The technology formerly that documents 1 is described is A П-12 a type frequency meter, and it surveys all errors≤± 1%, has adopted earlier to measure the vibration period, is calculated the formula of stress then by calculating formula.When implementing verification for the checking table of the fixed degree of value for A П-12 type, the length L 〉=3m of tested steel wire, reinforcing bar and steel cable; By surveying stress measurement error≤4% of calculating in week.
The 3rd article of the 2nd regulation of China standard GB 204-23, steel wire prestress franchise 5%.When detecting instrument dynamometry error was 4%, detected power value contrast prestress design load judged when whether qualified it is that only ± 1% can affirm acceptable ranges, unsubstantiated scope reaches 16%, and all the other then are defective certainly.See Figure of description 1.By accompanying drawing 1 as seen, because acceptability limit is too small certainly, the prestressed component that some is qualified can not obtain making economically to cause damage certainly.And the manufacturing process that portioned product is arranged in the prestressed component production technology makes testing conditions be limited to steel wire length overall＜3m.In addition, on-the-spot detect that prestress value requires as early as possible must the value of exerting oneself so that the adjustment stretching force, above-mentioned measuring earlier frequency or cycle checked the dynamometry formula of chart or calculating then, work efficiency is low in practicality, error is big.
Dynamometry error of the present invention≤1.5% can directly be read the stretching force value from the display screen of instrument, tested steel wire length overall 〉=2m.
Documents 2: high precision shows that directly forceful string opens the dynamometry circuit of (drawing) power, GK35103735.
Documents 2 described circuit reach in the sampling time of real-time frequency measurement under 3 seconds the prerequisite, improve counting precision.Little when wire tensioning force, the shake slow situation that frequently decays of steel wire can realize.For example, dynamometer span 60cm, diameter phi 5 wire tensioning forces 7.2～10KN, the time that measures the frequency that effectively shakes will continue more than 10 seconds.But when stretching force was 23.5KN, the duration under equal test condition was no more than 1.5 seconds.As can be known, after wire tensioning force increased, documents 2 described circuit can not normally be sampled.Except that the problem in above-mentioned sampling time, can not satisfy the requirement of calculating in real time after wire tensioning force increases the computing time of documents 2 described circuit.The reasons are as follows: the stretching force scope is little, for example, 7.2～10KN, its power is function N=A frequently 0+ A 1The f match can be satisfied the requirement of dynamometry precision.And stretching force increases, and after the corresponding increase of dynamometry scope, then must use N=A 0+ A 1F+A 2f 2The dynamometry accuracy requirement is just satisfied in match.For example, dynamometry scope 7.2～23.5KN uses N=A 0+ A 2The f match, dynamometry error＞3% of its Theoretical Calculation, the dynamometry error of making instrument is used N=A at least＞4% 0+ A 1F+A 2f 2Match, dynamometry error＜0.1% of Theoretical Calculation, the dynamometry error about 1% of trial-production instrument.In the mentioned portable steel force detecting apparatus of documents 2, calculate N=A in real time 0+ A 1The time of f is not more than 2 seconds; And calculate N=A with the circuit of same principle 0+ A 1F+A 2f 2Time be not less than 5 seconds.Therefore, duration is no more than 1.5 seconds when effectively shaking frequently, and then documents 2 described circuit can not be finished real-time calculating, in a word, because the requirement of sampling time and computing time, documents 2 described circuit are not suitable for the condition after wire tensioning force increases.
In the engineerings such as China's building, railway and traffic, cold-drawn low-carbon wire and various carbon element (high-strength) steel wire are arranged as the steel wire of presstressed reinforcing steel, and the low-alloy of new development (in strong) steel wire.External steel wire as presstressed reinforcing steel is high tensile steel wire only.With φ 5 is example, the stretching force scope practicality 7.2～10KN of low-carbon (LC) cold drawn wire; And high, medium-strength steel wire is 7.2～23.5KN.Documents 2 described circuit are only applicable to cold-drawn low-carbon wire, and circuit of the present invention can be used for above-mentioned all kinds of steel wire.
Documents 3: portable dynamometer-fart measuring with method of oscillatory frequency, GK35103739.
Documents 3 described dynamometers have adopted energy-storaging spring formula whipping mechanism; There is the rubber elasticity part to absorb in the clamping body lower end and hits the reflection wave that shakes; Linkage assembly, excentric shaft slide block mechanism clamp steel wire; The flank attack that hand hammer the is arranged on steel wire span length center steel wire that shakes.
Adopt energy-storaging spring formula whipping mechanism, the power with energy-storaging spring under the hand when operation need make dynamometer place on ground or a certain load plane, could be spring compression; The rubber elasticity part also needs to place the effect that could realize absorbing reflection wave on ground or a certain load plane.Therefore the dynamometer of this mechanism is only applicable in the tensioning process of long-line pedestal.And outside the short-term mould in the tensioning process, because the steel wire length overall is very short, rigidity is big, the shared height dimension of rubber elasticity part causes jaw can not clamp steel wire and keeps the original stress of steel wire.In addition, in the arrangement of reinforcement operating mode of actual prestressed component, layered configuration steel wire or steel wire power are arranged from load plane situation very far away, the dynamometer that documents 3 is described can not be used.
When adopting the excentric shaft slide block mechanism to clamp steel wire, certain as eccentric size, then ram travel is certain, when steel wire diameter changes, need add parallels, with the increase and decrease numerical value of compensation diameter.This makes the dynamometry operation add workload.
The side that the hand hammer that shakes is arranged in steel wire span length center is hit in employing, since hit shake a little not corresponding to the standing wave node of steel wire fundamental frequency in the span length, so in the power response procedure that hits the back steel wire that shakes, increased an additive factor, made and stablize growth transit time that the fundamental frequency appearance needs.Unlikely generation appreciable impact under the situation that though this is little to wire tensioning force, amplitude fading is slow, but very big at wire tensioning force, when amplitude fading is very fast, growth will take the frequency measurement time transit time, make to measure the time shortening of stablizing fundamental frequency, reduced the operating mode scope that dynamometer is suitable for.
In a word, above-mentioned documents 1,2,3 described technology formerly all fail to realize simultaneously: 1, steel wire length overall 〉=2m, and steel wire layered arrangement, steel wire be tensioning process outside the very far away or short-term mould apart from the load plane; 2, wire tensioning force is in whole usage ranges (comprising φ 3, φ 4, φ 5 all kinds of steel wires); 3, detect error≤1.5% of wire tensioning force; 4. directly show the stretching force value.But the present invention can realize above-mentioned whole requirement simultaneously.The dynamometer of this instrument is also with the function that detects steel wire diameter, so that directly revise the influence of diameter deviation at the scene; And when tested steel wire diameter changes, need not to adjust additional operations such as parallels.
This instrument comprises dynamometer and calculation display two parts.Realize that ergographic structure of the present invention sees Figure of description 2, accompanying drawing 3; Ergographic main body is a panel 1, and each portion mechanism is installed on the panel 1.Realize that the circuit of calculation display of the present invention sees accompanying drawing 4, accompanying drawing 5.Accompanying drawing 6
In accompanying drawing 2,3: 1-dynamometer panel, the rotary handle of 2-binding clasp, 3-detects the graduated ring of steel wire diameter, the swivel nut of 4-differential thread, the screw rod of 5-differential thread, 6-upper jaw, the 7-lower jaw, the tested steel wire of 8-, 9-left side absorbing bar, the 10-sensor, 11-right side absorbing bar, 12-five core shielded cable joints, 13-starting of oscillation signaling switch, 14-signaling switch briquetting, 15-absorbing handgrip, 16-absorbing magnet steel, 17-protects magnetic armature, (mark 2-7 has together at accompanying drawing 2 right sides symmetry place)
Dynamometer work is as follows: tested steel wire 3 is placed between the upper and lower jaw 6,7, and its span is 60cm, turn rotary handle 2, drive swivel nut 4 rotations, and make screw rod 5 moving linearlies, the upper jaw 6 of depress spiro rod 5 lower ends is so steel wire 8 is clamped between the upper and lower jaw 6,7.Differential thread has worked to amplify power.And because the decelerating effect of differential thread, it only is the part of pitch that handle 2 revolves screw rod 2 strokes that turn around, thereby has improved resolution.Utilize this characteristics, can detect steel wire diameter by the graduated ring 3 usefulness pairing comparision that detect steel wire diameter.Since the screw mechanism moving linearly, the stroke variable size.When steel wire diameter changes, needn't add the parallels adjustment.
After steel wire 8 is compacted, push absorbing handgrip 15 lightly earlier, left and right sides absorbing bar 9,11 lower ends are ridden on the tested steel wire 8, carried absorbing handgrip 15 again, stopped also adhesive until protecting magnetic armature 17.So free vibration attenuation is made in steel wire 8 starting of oscillations.The mechanism of above-mentioned starting of oscillation is divided into three parts: the applied load that 1, rides on the steel wire 8 sheds; 2, the magnetic circuit that forms through left and right sides absorbing bar 9,11 and steel wire 8 of absorbing magnet steel 16 is opened between left and right sides absorbing bar 9,11 and steel wire 8 and produces suction to steel wire; The vibration that when 3, absorbing bar upper end bump is protected magnetic armature 17 dynamometer is impacted and produce passes to steel wire 8 through jaw.Because left and right sides absorbing bar 9,11 is distributed in the both sides of steel wire span length mid point, symmetric arrangement, so the effect of above-mentioned three part mechanism is left-right symmetric, help forming with left and right sides jaw is the standing wave of node, the time of its dynamics transient process is shorter, and this kind absorbing operation need not the counter-force on ground or certain load plane.
When left and right sides absorbing bar 9,11 moved upward, the signaling switch briquetting 14 that fuses with it also moved upward, and has compressed starting of oscillation signaling switch 13.After the starting of oscillation of tested steel wire signal, the mechanical oscillation signal of steel wire changes electric signal into through sensor 10, amplifies through prime amplifier 18 again.The starting of oscillation signal that electric signal after the preposition amplification and starting of oscillation switch 13 send sends the calculation display of this instrument to by 12 outputs of five core shielded cable joints.
Fig. 4 has described and has realized circuit of the present invention: 10-sensor, 12-five core shielded cable joints, 13-starting of oscillation signaling switch, the 18-prime amplifier, 19-sampling holder, 20-multiplier, the 21-arithmetic and control unit, 22-counter, 23-frequency divider, the 24-crystal oscillator, the 25-code translator, the 26-display screen, steel wire starting of oscillation signal is by starting of oscillation signaling switch 13, enter arithmetic and control unit 21 through cable splice 12, as the zero point of starting of oscillation sequential.After the time-delay, arithmetic and control unit 21 keeps its electric quantity signal with the steel wire starting by set sequential control sampling holder 19, and the mechanism of sampling holder 19 is seen Fig. 5.Its sampling time is no more than 1 second, can keep for a long time adopting the frequency value of shaking constant.Arithmetic and control unit 21 is by the information frequently of shaking that keeps.The time reference that crystal oscillator 24 and frequency divider 23 are supplied with, multiplier 20 sum counters 22 are realized N=A 0+ A 1F+A 2f 2Calculating.Computational accuracy is met the requirements and simplify circuit with the method for transformation calculations parameter.At last, by display screen 26 demonstrations of liquid crystal, and keep result calculated, i.e. steel wire stretching force value N.
Fig. 5 has described the principle of sampling hold circuit: 19-sampling holder, 20-multiplier, 22-counter, 23-frequency divider, 24-crystal oscillator, the frequency converter in the 27-arithmetic and control unit 21, the main door in the 28-arithmetic and control unit 21.Steel wire shakes frequently, and f is nf through multiplier 20 frequencys multiplication.Be defeated by main door 28 again, give main door 28 by crystal oscillator 24, frequency divider 23 base information when frequency converter 27 outputting standards in addition.Counter 22 is defeated by in the pulse of main door 28 outputs.Counter 22 has enough numerical digits, accurately to reflect the information frequently of shaking.By counter 22 this frequency information of shaking is defeated by sampling holder 19 then.Being characterized as of this sampling holder 19: 1, the holding circuit of full digital, but under the situation of not cutting off the electricity supply the long preservation information frequently of shaking, be not subjected to the influence of environment temperature, electromagnetic field and mains fluctuations, keep numerical value constant; 2, precision height, for example, counter 22 adopts five, sampling holder 19 to adopt four, makes 22 full in counter with the method for adjusting frequency n but does not overflow, and then the vibration frequency precision of Bao Chiing is not less than 0.1%; When being necessary, can increase numerical digit, further improve precision; 3, owing to calculate N=A 0+ A 1F+A 2f 2The main door 28 of Shi Suoyong, counter 23 etc. all can be general when sampling, and when the enforcement sampling kept function, it was special the setting that sampling holder 19 is only arranged, and need not other circuit components, so the economic benefit height of the sampling of this circuit maintenance function; 4, the sampling time is not more than 1 second, and practical application is the hundreds of millisecond, can increase the fast situation of back amplitude fading at wire tensioning force and be issued to sampling precision.
Fig. 6 has described calculating parameter translation circuit principle: the 19-sampling holder, the 20-multiplier, the 22-counter, the 23-frequency divider, 24-crystal oscillator, 25-code translator, the 26-display screen, main door in the 28-arithmetic and control unit 21, the switch in 29～33-arithmetic and control unit 21, the scrambler in the 34-multiplier 20.With crystal oscillator 24, frequency divider 23 output frequencies is f 1The pulse of/nf, wherein f is that steel wire shakes frequently.Through switch 29, exporting a width is nf/f 1Square wave base when giving main door 28 as the opening the door of main door 28.Be f by crystal oscillator 24, frequency divider 23 output frequencies in addition 2Pulse give multiplier 20.Insert A in the scrambler 34 in advance 1, A 2Deng coefficient, and the A that in computation process, inserts by switch 33 2F.Determine the action of switch 31～33 by sequential, certain coefficient is defeated by multiplier 20 from scrambler 34.As output is A 2, then multiplier 20 output frequencies are A 2f 2Pulse give main door 28, as the count pulse of main door 28.So being defeated by the umber of pulse of counter 22, main door 28 is (A 2f 2Nf)/(f 1), n, f in the formula 1, f 2It is the constant of setting.When setting (nf 2)/(f 1)=100 o'clock, then the numerical value in the counter 23 is 10A 2F.Calculate so item by item, promptly obtain N=A 0+ A 1F+A 2f 2
Technology formerly, is surveyed in all circuit, when frequency measurement at general general main door (gate) method frequency measurement, measured signal is by the main door of count pulse input, the time interval benchmark of standard is by the main door of square wave input, and the step-by-step counting of then main door output is the vibration frequency number, and unit is Hz or its * 10 nHz(n is positive and negative integer); When surveying week, measured signal is in square wave, and the standard time, the step-by-step counting of then main door output was the vibration period number by main of count pulse input, and unit is second, millisecond etc.As in general frequency measurement circuit, calculate A item by item 1F, A 2F, (A 2F) during f, signal frequency f use earlier the multiplier frequency multiplication, again by the main door of count pulse input.But this calculating parameter translation circuit is different from above-mentioned general frequency measurement, surveys all circuit.It is characterized by: carrying out the function N=A of frequency 0+ A 1F+A 2f 2Calculating item by item the time, shake frequently that the signal packet of f is contained in the main door 29 of input in the square wave, and set n, f 1, f 2Etc. auxiliary parameter, reach with the similar method of surveying week that has coefficient, realize the polynomial computation of frequency f.The actual benefit of this parameter transformation circuit is: select numerical digit and n, f according to actual frequency range and accuracy requirement during design 1, f 2Etc. auxiliary parameter, realize circuit reduction, than the used element much less of universal circuit, can meet accuracy requirement again.One of example of its benefit: this parameter transformation circuit can directly extract the information that keeps from have the subtraction counting commodity integrated package that put number end, and is transformed to square wave and transports to main door 28, so circuit is very simple.

Claims (7)

  1. A kind of steel wire prestress detecting instrument based on the method for oscillatory frequency principle, it includes short span (60cm) dynamometer and calculation display, it is characterized in that its dynamometer includes:
    1, differential screw formula clamp system;
  2. 2, detect the graduated ring of steel wire diameter with relative method;
    Also include symmetrical starting of oscillation mechanism, wherein:
  3. 3, precompressed steel wire unloads starting of oscillation mechanism suddenly;
  4. 4, the absorbing bar starting of oscillation mechanism that has permanent magnet;
  5. 5,, make vibration pass to the starting of oscillation mechanism of steel wire by clamp system with knocking dynamometer itself; Include in its calculation display:
  6. 6, full digital sampling with high precision holding circuit.It under the situation of not cutting off the electricity supply, the information frequently but long preservation is shaken, numerical value is constant; Its counter will adopt five, and four of sampling holder employings make the full position of counter with the method for adjusting frequency n, but do not overflow, and the frequency precision of information that keeps shaking is not less than 0.1%, as increasing numerical digit, precision is further improved; When sampling keeps, can general-purpose computations N=A 0+ A 1F+A 2f 2The time circuit such as main door, counter, only need keep the circuit of numerical value itself; Sampling time is not more than 1 second.
  7. 7, calculating parameter translation circuit, it is carrying out frequency function N=A 0+ A 1F+A 2f 2Calculating item by item the time, shaking frequently, the signal packet of f is contained in the main door of input in the square wave; Set n, f 1, f 2Etc. auxiliary parameter, reach the polynomial computation that realizes frequency f with the similar method of surveying week that has coefficient; Select numerical digit and n, f according to actual frequency range and accuracy requirement during design 1, f 2Etc. auxiliary parameter, realize circuit reduction, meet accuracy requirement again.
CN87104955.4A 1987-07-22 1987-07-22 Tension testing instrument for steel wires Expired CN1006088B (en)

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CN87104955.4A CN1006088B (en) 1987-07-22 1987-07-22 Tension testing instrument for steel wires

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Application Number Priority Date Filing Date Title
CN87104955.4A CN1006088B (en) 1987-07-22 1987-07-22 Tension testing instrument for steel wires

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CN87104955A true CN87104955A (en) 1988-04-27
CN1006088B CN1006088B (en) 1989-12-13

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100547381C (en) * 2006-11-27 2009-10-07 江苏兴达钢帘线股份有限公司 A kind of examining apparatus for spot weld of steel shade thread
CN101109691B (en) * 2007-07-30 2011-04-27 山东省交通厅公路局 Device and method for metallic rod body material stress corrosion test
CN106501643A (en) * 2016-10-21 2017-03-15 湘潭电机股份有限公司 A kind of detection method of the resistance to pulling force of cable connector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100547381C (en) * 2006-11-27 2009-10-07 江苏兴达钢帘线股份有限公司 A kind of examining apparatus for spot weld of steel shade thread
CN101109691B (en) * 2007-07-30 2011-04-27 山东省交通厅公路局 Device and method for metallic rod body material stress corrosion test
CN106501643A (en) * 2016-10-21 2017-03-15 湘潭电机股份有限公司 A kind of detection method of the resistance to pulling force of cable connector
CN106501643B (en) * 2016-10-21 2018-11-16 湘潭电机股份有限公司 A kind of detection method of the resistance to pulling force of cable connector

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