CN1804544A - Displacement measuring apparatus for concrete temperature-pressure tester and application thereof - Google Patents

Abstract

The invention relates to a shift measuring device of the concrete temperature-stress tester, which comprises two suits of same measuring sub system distributed on the two sides of the central axis of the concrete test unit (1), each sub system is formed by a laser shift sensor (5) and a carbon fiber rod (3) parallels to the central axis; one end of the carbon fiber rod is fixed on the main rim of the tester by fixed seat (2) and the other end fixes a laser shift sensor; the rod is supported by a plurality of guiding seats (4) of the main rim; the laser (7) sent by the laser shift sensor is parallel to the test central axis; the laser returns to when it sends to the measuring point (8) of the active end; the digital quantity is transmitted to the upper machine or the display unit to process by the digital interface (6).

Description

The displacement measuring device of concrete temperature-pressure tester and application thereof

Technical field

The present invention relates to fields of measurement, particularly a kind of displacement measuring device of concrete temperature-pressure tester and application thereof, this device is non-contact type laser displacement measurement device.

Background technology

Constraint adjustable single axle temperature-pressure tester is a kind ofly to study the early stage hydration characteristics of concrete, stress development, deformation modulus and the equipment of characteristic such as creep.Concrete sample is applied certain pressure or changes the temperature of test specimen, and concrete sample all will produce certain deformation quantity.

Have only several companies and university being engaged in this Products Development at present at home and abroad.Abroad, related scientific research mechanisms such as Japanese Tokyo University and Switzerland are arranged at this testing machine of exploitation.At home, have only department of civil engineering, Tsinghua university building materials research institute to develop this testing machine at present.But, on the displacement measuring device of this testing machine, all adopted contact measuring apparatus both at home and abroad.

The measuring accuracy of concrete sample deformation quantity directly influences the performance of constraint adjustable single axle temperature-pressure tester.Measuring accuracy is high more, and the data of measurement more can be more effectively and reflected that accurately concrete is subjected to the characteristic of temperature and pressure distortion.At present in contact measuring apparatus, employing be that tangent displacement sensor directly is fixed on the support, the mode of measuring sonde contact on the movable end of testing machine.When the test piece deformation in the movable end, the also corresponding generation displacement of movable end and measuring sonde.The error of this metering system is made up of three parts: the error that error that the measuring error of displacement transducer self, contact point deformation produce and support deformation produce.Therefore the measuring error of contact displacement measuring device is above three's error sum.

Aspect the error of contact point deformation generation, because the deformation quantity of concrete sample is between 0.05～10 μ m, the contact point deformation quantity is between 0.01～1 μ m, therefore the error of contact point deformation generation is between 0.1%～10%, promptly in the worst case, the error that contact point deformation produces is 10%, the then serious distortion of the data of Ce Lianging.On the other hand, the deformation quantity of concrete sample and contact point deformation quantity exist overlapping interval, in case therefore the deformation quantity of concrete sample is between 0.01～1 μ m, in the worst case, what the data of measuring reflected is the deformation quantity of contact point fully, rather than the deformation quantity of concrete sample, therefore the lower limit of the measurement range of this contact type measurement mode is 1 μ m, be that to measure range be between 1～10 μ m to the contact type measurement mode, therefore contact point deformation will limit the measurement range of whole measuring system, thereby limited the function of testing machine, testing machine can't effectively be studied strong concrete.

Aspect the error of support deformation generation; because what adopt at present is that displacement transducer directly is fixed on the mode on the support; but support can be subjected to temperature and pressure to produce certain deformation usually; this deformation is between 0.005～0.1 μ m; the error that produces is 0.05%～1%; when the measuring accuracy of displacement transducer was 0.5%, the measuring accuracy of whole measuring system will be greater than 1.5%.

In addition, because the stressed back of concrete sample can produce swing at surface level, contact measuring apparatus is not also considered the influence of this swing to measuring accuracy at present.

Summary of the invention

Technical matters to be solved by this invention is: a kind of displacement measuring device and application thereof of concrete temperature-pressure tester are provided.Under non-contacting state, what the data of this measurement device reflected is the deformation quantity of concrete sample, thereby can reflect the result of test really.

The present invention solves its technical matters and adopts following technical scheme:

Device provided by the invention is the non-contact type laser displacement measurement device of concrete temperature-pressure tester, be provided with the identical measurement subsystem of two covers, they are distributed in the both sides of concrete test specimen axis symmetrically, and each subsystem is made up of with the carbon fiber rod parallel with the test specimen axis laser displacement sensor.One end of carbon fiber rod is contained in by holder on the main engine bed of testing machine, and the other end is promptly installed laser displacement sensor near the movable end place of test specimen, and its barred body is then by several rod guide supports that are fixed on the main engine bed.The laser displacement sensor emitted laser is parallel with the test specimen axis, and laser returns after being mapped to the measurement point of movable end.The digital quantity of this measurement device is sent to host computer by digital interface or display unit is handled.

The non-contact type laser displacement measurement device of concrete temperature-pressure tester provided by the invention can carry out laser triangulation or measurements by laser interferometry to concrete sample.

The present invention compared with prior art has following main beneficial effect:

One. there is not contact point, eliminated the error that contact point deformation produces, improved the precision of measuring, widened the range of measuring.

They are two years old. and adopt the little carbon fiber rod fixed laser displacement transducer of temperature deformation coefficient, can eliminate of the influence of the error of support deformation generation the displacement transducer measuring accuracy.

They are three years old. and whole heed contacted measure error in measure and range depend on the sum of errors range of laser displacement sensor fully, and the resolution of whole heed contacted measure device is not less than 0.01 μ m, measuring error is 0.03%, measures the range lower limit less than 0.05, and the upper limit is greater than 10 μ m.What the data of measuring reflected is the real test findings of concrete sample.

They are four years old. and measurement result adopts the digital interface transmission, and antijamming capability is strong.

They are five years old. and adopt the identical measurement subsystem of two covers, measurement result is got the mean value of two cover measurement subsystems, has eliminated the stressed back of the concrete sample measuring error that swing brings in surface level.

Description of drawings

Fig. 1 is the displacement measuring device floor map of concrete temperature-pressure tester.

Fig. 2 is the left view of guide holder 4.

Fig. 3 is the vertical view of guide holder 4.

Fig. 4 is the laser triangulation displacement principle.

Fig. 5 is laser interferometry displacement principle figure.

Embodiment

Device provided by the invention is a kind of contactless displacement measuring device of concrete temperature-pressure tester.

The invention will be further described below in conjunction with embodiment and accompanying drawing.

One. the non-contact type laser displacement measurement device of concrete temperature-pressure tester

Its structure such as Fig. 1, Fig. 2 are with shown in Figure 3: be provided with the identical measurement subsystem of two covers, they are distributed in the both sides of concrete test specimen 1 axis symmetrically, and each subsystem is made up of with the carbon fiber rod 3 parallel with test specimen 1 axis laser displacement sensor 5.One end of carbon fiber rod 3 is contained on the main engine bed of testing machine by holder 2, the other end is promptly installed laser displacement sensor 5 near movable end 9 places of test specimen 1, its barred body then with several guide holder 4 movable supporting, barred body can be in the pilot hole 11 of guide holder 4 moves freely aspect axial along barred body like this.Guide holder 4 is fixed on the main engine bed it by bolt by hole 10.Laser displacement sensor 5 emitted laser 7 are parallel with test specimen 1 axis, and laser 7 returns after being mapped to the measurement point 8 of movable end 9.The digital quantity of this measurement device is sent to host computer by digital interface 6 or display unit is handled.

Above-mentioned carbon fiber rod 3 can be made by PAN-based carbon fiber, and its length is 0.5～1.5m, and diameter is 0.5～2cm.Digital interface 6 can be selected a kind of interface in RS485 interface, RS232 interface and the USU interface.

The measuring accuracy height of this device is not less than 0.01 μ m.

Two. the application of the non-contact type laser displacement measurement device of concrete temperature-pressure tester

Embodiment one: the heed contacted measure device adopts laser triangulation

As shown in Figure 4: after the light beam of generating laser 12 focuses on through condenser lens 13, be mapped to concrete sample 1 movable end 9 certain a bit after, the segment beam of scattering is mapped on the charge-coupled image sensor 15 through behind the imaging len 14.When movable end 9 after having moved displacement x on the beam direction, can calculate at the displacement y of charge-coupled image sensor 15 accordingly.Perpendicular to straight line BO, the area of triangle ABO is as Fig. 4 straight line AD:

S＝AD·BO＝AB·AO·sin(π-φ) (1)

Have the cosine law to get again:

BO ²＝AB ²+AO ²+2·AB·AO·cosφ (2)

Put in order:

$\mathrm{AD}=\mathrm{AB}\·\sin \mathrm{\φ}\·\sqrt{\frac{1}{{\left(\frac{\mathrm{AB}}{\mathrm{AO}}\right)}^2+2\·\frac{\mathrm{AB}}{\mathrm{AO}}\·\cos \mathrm{\φ}+1}}----\left(3\right)$

When imaging lens 14 horizontal enlargement ratios are β, that is:

y＝β·AD (4)

Then

$y=\mathrm{\β}\·\mathrm{AB}\·\sin \mathrm{\φ}\·\sqrt{\frac{1}{{\left(\frac{\mathrm{AB}}{\mathrm{AO}}\right)}^2+2\·\frac{\mathrm{AB}}{\mathrm{AO}}\·\cos \mathrm{\φ}+1}}----\left(5\right)$

Because AB much smaller than AO, then has: y=β x.

Corresponding displacement takes place along with the deformation of concrete sample 1 in the Focus Club that laser light reflected forms on charge-coupled image sensor 15, charge-coupled image sensor 15 can be responded to the position coordinates of focus on sensor, main control circuit 16 becomes the corresponding digital amount with the conversion of signals of charge-coupled image sensor 15 inductions, and digital interface 6 passes to host computer or display unit with the digital quantity of measuring.

In order to reduce movable end 9 stressed backs in the error of bringing along swing in the surface level of axis, the mean value of two cover measurement subsystem Displacement Measurement amounts, i.e. the deformation quantity γ=(y of test specimen are measured in the deformation of test specimen ₁+ y ₂)/2, wherein y ₁, y ₂It is respectively the displacement of the movable end 9 of two cover systematic surveys.

Embodiment two: the heed contacted measure device adopts interferometry

As shown in Figure 5: the laser beam of being sent by generating laser 17 is divided into two light beams behind the polarizer 18 and quarter wave plate 19 arrival spectroscopes 22, one is folded light beam, and another is a transmitted light beam.Folded light beam reflects back into spectroscope 22 behind supplementary lens 20 and stationary mirror 21.Transmitted light beam returns to arrive spectroscope 22 through movable end 9 back reflections that supplementary lens 23 arrives concrete sample 1, and folded light beam and transmitted light beam form focus through condenser lens 24 backs on charge-coupled image sensor 25 after spectroscope 22 places interfere.

Because the optical path length of folded light beam is constant. and the optical path length of transmitted light beam is to change with moving of movable end 9.Therefore when the optical path difference of two-beam is the even-multiple of laser half-wavelength, light beam mutual superposition and strengthening forms bright spot on charge-coupled image sensor 25; When optical path difference was the odd-multiple of laser half-wavelength, the two-beam phase of wave was offset mutually, formed dim spot on charge-coupled image sensor 25.As a result, the synthetic light intensity of two bundles is strengthened or is weakened, and is that the optical path difference of two-beam decides.And the light path of folded light beam is changeless, and the light path of transmitted light beam then changes with the displacement of movable end 9, and for this reason, the light and shade of interference point changes, and directly can measure the change in displacement of movable end 9.

The whenever mobile γ of movable end 9/2 distances, the light path of transmitted light beam has just changed a wavelength γ, changes so interference point just produces the light and shade of one-period, and this light and shade changes can convert digital quantity to by main control circuit 26.So the periodicity k that the interference point when being moved by movable end 9 changes just can obtain the displacement y of testee, that is: y=k γ/2.

Get the mean value of two cover measurement subsystem Displacement Measurement amounts, through digital interface circuit 6 digital quantity of measuring is passed to host computer or display unit then.

Claims (6)

1. the displacement measuring device of a concrete temperature-pressure tester, the non-contact type laser displacement measurement device that it is characterized in that concrete temperature-pressure tester, be provided with the identical measurement subsystem of two covers, they are distributed in the both sides of concrete test specimen (1) axis symmetrically, and each subsystem is made up of with the carbon fiber rod (3) parallel with test specimen (1) axis laser displacement sensor (5); One end of carbon fiber rod (3) is contained on the main engine bed of testing machine by holder (2), the other end promptly locates to install laser displacement sensor (5) near the movable end (9) of test specimen (1), and its barred body is then by several guide holders (4) movable supporting that is fixed on the main engine bed; Laser displacement sensor (5) emitted laser (7) is parallel with test specimen (1) axis, and laser (7) returns after being mapped to the measurement point (8) of movable end (9); The digital quantity of this measurement device is sent to host computer by digital interface (6) or display unit is handled.

2. displacement measuring device according to claim 1 is characterized in that: carbon fiber rod (3) is made by PAN-based carbon fiber, and its length is 0.5～1.5m, and diameter is 0.5～2cm.

3. the displacement measuring device of concrete temperature-pressure tester according to claim 1 is characterized in that: a kind of in RS485 interface, RS232 interface and the USB interface of digital interface (6).

4. the displacement measuring device of concrete temperature-pressure tester according to claim 1 is characterized in that described displacement measuring device, and its measuring accuracy is not less than 0.01 μ m.

5. the non-contact type laser displacement measurement device of concrete temperature-pressure tester carries out laser triangulation to concrete sample (1), specifically: after the light beam of generating laser (12) focuses on through condenser lens (13), be mapped to concrete sample (1) movable end (9) certain a bit after, the segment beam of scattering is mapped on the charge-coupled image sensor (15) after through imaging len (14); When movable end (9) after having moved displacement x on the beam direction, calculate at the displacement y of charge-coupled image sensor accordingly, laser light reflected (7) goes up the Focus Club that forms at charge-coupled image sensor (15) and along with the deformation of concrete sample (1) corresponding displacement takes place, charge-coupled image sensor (15) can be responded to the position coordinates of focus, and convert the corresponding digital amount to by main control circuit (16), get the mean value of two cover measurement subsystem Displacement Measurement amounts, through digital interface (6) digital quantity of measuring is passed to host computer or display unit then.

6. the non-contact type laser displacement measurement device of concrete temperature-pressure tester carries out measurements by laser interferometry to concrete sample (1), specifically: the laser beam of being sent by generating laser (17) is divided into two light beams behind the polarizer (18) and quarter wave plate (19) arrival spectroscope (22), article one, be folded light beam, another is a transmitted light beam; Folded light beam is got back to spectroscope (22) through supplementary lens (20) and stationary mirror (21) back reflection, transmitted light beam returns to arrive spectroscope (22) through movable end (9) back reflection that supplementary lens (23) arrives concrete sample (1), and these two light beams are located to interfere at spectroscope (22); The whenever mobile γ of movable end (9)/2 distances, the light path of transmitted light beam has just changed a wavelength γ, so just producing the light and shade of one-period, interference point changes, this is changed to the displacement y of concrete sample (1), the variation of charge-coupled image sensor (25) induction interference point, main control circuit (26) becomes digital quantity with the electrical signal conversion of charge-coupled image sensor (25) induction, get the mean value of two cover measurement subsystem Displacement Measurement amounts, through digital interface (6) digital quantity of measuring is passed to host computer or display unit then.

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