CN101487790B - Fast measuring apparatus and measuring method for mechanical property of thin slab type wood materials - Google Patents
Fast measuring apparatus and measuring method for mechanical property of thin slab type wood materials Download PDFInfo
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- CN101487790B CN101487790B CN2009100784179A CN200910078417A CN101487790B CN 101487790 B CN101487790 B CN 101487790B CN 2009100784179 A CN2009100784179 A CN 2009100784179A CN 200910078417 A CN200910078417 A CN 200910078417A CN 101487790 B CN101487790 B CN 101487790B
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Abstract
The invention relates to a device for quickly measuring the mechanical property of a sheet-typed woody material, consisting of two parts: a mechanical structure part and a data processing part. The mechanical structure part also comprises four parts: a basic frame part, a specimen clamping part, an initial stressing part and a vibration sensing part. The data processing part comprises a signal conditioning box and a computer. The measuring method mainly comprises the following steps of: (1) accurately setting the initial displacement value; (2) clamping the specimen; (3) setting the storage directory and the filename of the measurement result, and inputting the basic parameters of the specimen; (4) zeroing the displacement output of the laser sensor; (5) measuring the static MOE; (6) measuring the dynamic MOE; (7) storing and displaying the measurement result. The measuring device can measure the mechanical property of the sheet-typed woody material quickly and conveniently. Compared to the traditional measuring devices and methods, the device and the method for quick measuring the mechanical property of a sheet-typed woody material in the invention save time and cost and are easy for operation.
Description
Technical field
The present invention relates to a kind of mechanical property of thin slab type wood materials rapid measurement device and measuring method, belong to material mechanical performance test detection range.
Background technology
The thin slab type wood material is meant that thickness is fiberboard, particieboard, Wood-plastic material plate (Wood-fiber plastic), artificial veneer, paper holder wrappage (Pulp molded products) of 1～5mm etc.Application quantity is huge at present, and main application comprises: building materials, as basic module, the structure integrated timber dash board etc. of D light Structural Engineering composite wood boards (3D Engineered Composites); Decorating and renovating material is mated formation with backing plate as wall panel, floor, floor in nonweight-bearing partition plate, wallboard, roofing top board, the compartment etc. etc.; Wrappage are as container plate, various packaging boxboard; Furniture material is as various table tops, shelf; Electric appliance casing is as sound equipment housing, tv shell etc.This class material development at present is very fast, but comparatively ripe mechanical property Fast Detection Technique, method and instrument are never arranged as timber, thick wood-based plate and thin paper.
To large scale timber and dimension stock, two kinds of popular fast dynamics method for testing performance are free beam supporting vibratory drilling method and stress wave.Two kinds of methods all are used to detect the elastic modulus of timber.In vibratory drilling method, mainly measure vibration frequency, size and the weight of timber.And stress wave is mainly measured the travel-time and the calculating elastic modulus of knock wave.
To the thin slab type wood material, free beam supporting vibratory drilling method is out of use because measurand weight is too light thus in vibration processes can not with supporting between keep well contacting, thereby obtain vibration signal less than necessity.Simultaneously, vibration frequency is also extremely difficult to be recorded, because contact with supporting for keeping, must make the amplitude of measurand very little.And stress wave also is difficult to be used for the quick measurement of this class material mechanical performance because sensor is difficult for fixing.
The present invention is based on semi-girder flexural deformation theory and theory of oscillation, promptly carries out work according to the correlationship between the distortion of wood materials thin plate semi-girder test specimen static buckling, vibration characteristics and its elastic modulus.At first the test specimen free end is applied an accurate initial displacement, utilize the size of force cell sensing power simultaneously; According to semi-girder static buckling Deformation Theory, the static buckling elastic modulus that utilizes program to calculate test specimen in real time (is called for short: static MOE) again.Discharge the test specimen free end then, make test specimen produce free vibration, by the free vibration displacement signal of laser sensor sensing test specimen, after machine carries out data acquisition and processing (DAP) as calculated, draw the dynamic bending elastic modulus (be called for short: dynamically MOE) of test specimen and damping ratio etc.
Summary of the invention
The objective of the invention is to propose a kind of mechanical property of thin slab type wood materials rapid measurement device and measuring method, static buckling distortion and free vibration by thin slab type wood Material Cantilever Beam test specimen, and the analysis of data-signal and calculating, static buckling elastic modulus (static MOE), dynamic bending elastic modulus (dynamically MOE) and the vibration damping of measuring the thin slab type wood material compares etc.
Technical scheme of the present invention is as follows:
A kind of mechanical property of thin slab type wood materials rapid measurement device of the present invention, mainly form by two parts: physical construction part and data processing section, as shown in Figure 1.The major function of physical construction part is that clamping, adjustment, the initial displacement of test specimen applies, the sensing of starting force sensing, exciting and vibration signal.In the physical construction part, test specimen is by vertical clamping, upper end clamping, lower end freedom.Test specimen clamping part position is adjustable up and down, is suitable for measuring the test specimen of different length.The laser sensor adjustable positions is adapted to the original distortion of difference self of different test specimens.Drag hook position level is adjustable, is suitable for the test specimen free end is applied different initial displacements, can accurately set this initial displacement amount; After initial displacement applies, the size that force cell can the sensing starting force.In addition, after initial displacement applied, drag hook can discharge test specimen rapidly, realized the free vibration of test specimen.Force cell should be little range, precision force transducer, and laser sensor should be high accuracy displacement sensor.
The major function of data processing section is the conditioning of starting force signal and vibration signal, collection, the static buckling elastic modulus of handling, calculate test specimen, dynamic bending elastic modulus and vibration damping to be compared etc.Data processing section mainly is made up of signal condition box and computing machine.Force signal amplifier, laser sensor vibration signal amplifier, data collecting card etc. are arranged in the signal condition box.Be useful on the special software of data acquisition, processing in the computing machine.Data acquisition, process software can adopt any computer programming language establishment.
1.1 measurement mechanism physical construction part
As shown in Figure 2, measurement mechanism physical construction is divided into four parts again: basic framework part A, test specimen clamping part B, initial afterburning portion C, vibrating sensing part D.Basic framework partly is the support body of entire measuring device.Test specimen clamping part can make an end of test specimen fix, and constitutes the crooked and vibration of test specimen semi-girder, prevents the test specimen run-off the straight and moves.Initial afterburning part can provide the initial displacement and the starting force of horizontal direction for effectively the test specimen free end, and can adopt the starting force signal by computing machine, calculates static MOE.The vibrating sensing part can be obtained the displacement vibration signal in the test specimen semi-girder vibration processes exactly and be sent to computing machine, and computing machine draws dynamic MOE by data analysis, processing.
As shown in Figure 3, the basic framework part A mainly is made up of base 1 and support 14; Base 1 is fixedlyed connected with support 14; On base 1, be fixed with line slideway 20, on support 14, be fixed with line slideway 16; 1 of line slideway 20 and base, and line slideway 16 is connected by screw retention with 14 on support.
As shown in Figure 3 and Figure 4, test specimen clamping part B is made up of screw 7, gland 8, pressing plate 34, bearing 15, latch 11 (two), bent plate 12, slide 35 etc.Gland 8 is fixed on the bearing 15, and bearing 15 is fixed on the slide 35, and slide 35 constitutes the line slideway group with guide rail 16.Slide 35 is fixedly linked with bent plate 12, in the pilot hole that latch 11 inserts on the supports 14, realizes the location of upper-lower position of whole test specimen clamping part and fixing.The pilot hole (a, pilot hole 1, b, pilot hole 2, c, pilot hole 3, d, pilot hole 4) that four pairs of differing heights are arranged on the support 14, every pair of pilot hole is symmetrically distributed in line slideway 16 both sides (only having shown four pairs of pilot hole one side positions on Fig. 3).Every pair of pilot hole is realized " test specimen clamping part " upright position, i.e. the test specimen of a corresponding series length; The pilot hole of four pairs of differing heights is realized " test specimen clamping part " four upright positions, promptly corresponding to the test specimen series of four different lengths.As required, on differing heights, can increase pilot hole, even make continuous adjustable structure, to be suitable for the measurement demand of different length test specimen.
As Fig. 3 and shown in Figure 5, initial afterburning portion C is made up of slide 23, bearing 2, leading screw 21, force cell 3, web member 4, drag hook 5 etc.Drag hook 5 is connected with web member 4 by bearing pin 40, and drag hook 5 can rotate around bearing pin 40.Be with torsion spring 37 on the bearing pin 40, be used for to 5 one holding powers that make progress of drag hook, set screw 36 can keep drag hook 5 levels.Bearing 2 is fixedly connected with slide 23.Depress drag hook 5, hook test specimen 6 lower ends, force cell 3 can sensing go out initially (static state) power.Moving of drag hook 5 horizontal levels can realize by rotating threaded shaft 21.Baffle plate 38 is fixedly connected with supporting seat 27.Nut 19 and nut 22 are used for locking leading screw 21 after the horizontal position adjustment of drag hook 5 is finished, keep the fixed distance of 27 of drag hook 5 and supporting seats constant.
As shown in Figure 6, vibrating sensing part D is made up of laser sensor 25, upper support seat 26, supporting seat 27, slide 31, leading screw 28, bearing 29 etc.Bearing 29 is fixed on the base 1 by four screws 30.Link to each other by screw retention between laser sensor 25, upper support seat 26, supporting seat 27, slide 31, four.Rotating threaded shaft 28 can be regulated laser sensor 25 horizontal levels.Baffle plate 32 is fixed together with supporting seat 27.
1.2 measurement mechanism data processing section
The data processing section of measurement mechanism mainly is made up of signal condition box and computing machine.
1.2.1 signal condition box
As shown in Figure 7, the signal condition box is made up of force signal amplifier, laser sensor vibration signal amplifier, data collecting card, direct supply etc.Force signal amplifier and vibration signal amplifier are supporting with selected force transducer and laser sensor respectively, generally require sensor manufacturer to provide with sensor is supporting.Data collecting card links to each other with two amplifiers respectively, connects with computing machine simultaneously; Direct supply links to each other with two amplifiers respectively, and the direct current supply of certain voltage is provided for two amplifiers.Direct current supply voltage is decided according to the requirement of selected sensor and amplifier.
The quick measuring method of a kind of mechanical property of thin slab type wood materials of the present invention is specially following steps:
(1) accurately sets the initial displacement value.
Adjust the upright position of " test specimen clamping part B ", select the sheet metal of an any surface finish, with the sheet metal clamping to measurement mechanism; Fine setting laser sensor 25 horizontal levels, to its output voltage be 0; Adjust the horizontal level of drag hook 5, the distance of preliminary surveying sheet metal left surface and drag hook 5 inside groove left margins; Keep the fixed distance of 27 of drag hook 5 and supporting seats motionless; Accurately measure the distance of sheet metal left surface and drag hook 5 inside groove left margins once more; This distance value is exactly the free-ended initial displacement value of a test specimen Δ.
(2) clamping test specimen.
According to different test specimen length, adjust the height of " test specimen clamping part B ", with test specimen 6 clampings on measurement mechanism.
(3) setting measurement storage directory and filename as a result, input test specimen basic parameter.
Open software, setting measurement is storage directory and filename as a result, input test specimen basic parameter; The test specimen basic parameter comprises: test specimen numbering (title), specimen width b (mm), specimen thickness t (mm), test specimen total length L (mm), test specimen free end initial displacement Δ (mm), test specimen mass M (g).The automatic calculation testing piece jib-length of software l deducts clamping length 50mm for the test specimen total length L.
(4) laser sensor displacement output zeroing.
After eliminating the test specimen clamping, himself influence of original distortion to measuring needs before formal the measurement laser sensor is aimed at the test specimen left surface zero point.Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, by rotating threaded shaft 28, fine setting laser sensor 25 horizontal levels, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.
(5) measure static MOE.
Manually the test specimen bottom is moved to right, and it is hung on the drag hook 5.Be equivalent to apply an initial displacement Δ to the test specimen free end.Click " beginning to measure " icon.Software collection initial displacement force signal P, acquisition time are 1 to several seconds; Calculate static MOE, show measurement result.
(6) measure dynamic MOE.
After static MOE measurement result showed, drag hook 5 was removed downwards, discharged test specimen 6 free ends, test specimen free vibration.Laser sensor 25 sense vibration displacements, software is discerned vibration signal automatically, and gathers, shows the vibration displacement signal, and acquisition time is the several seconds, calculates dynamic MOE.Concrete signal analysis, contents processing comprise: calculate (1) damping first natural frequency f
d, (2) calculate dampingratio, and (3) calculate undamped first natural frequency f, the dynamic MOE of (4) calculation testing piece.
(7) storage, demonstration measurement result.
Software is stored the test specimen measurement result automatically, comprising: test specimen is numbered (title), static buckling elastic modulus (static MOE), dynamic bending elastic modulus (dynamically MOE), vibration damping ratio, damping first natural frequency f is arranged
dWith undamped first natural frequency f.
Software shows three measurement results of test specimen: static MOE (when being shown in (5) EOS earlier), dynamic MOE and vibration damping ratio automatically.
So far, a measuring process finishes.
A kind of mechanical property of thin slab type wood materials rapid measurement device of the present invention and measuring method, its advantage and effect are: can measure the mechanical property of thin slab type wood material quickly and easily, comprise static buckling elastic modulus (static MOE), dynamic bending elastic modulus (dynamically MOE), vibration damping ratio, damping first natural frequency f is arranged
dWith undamped first natural frequency f.Compare with traditional measurement apparatus and method (3 or four-point bending measurement, stretching measurement etc.), measurement mechanism and measuring method that mechanical property of thin slab type wood materials of the present invention is measured have fast been saved time, cost, and be easy and simple to handle.
Description of drawings
Figure 1 shows that apparatus of the present invention composition frame chart
Figure 2 shows that apparatus of the present invention physical construction part synoptic diagram ()
Figure 3 shows that apparatus of the present invention physical construction part synoptic diagram (two)
Figure 4 shows that the test specimen clamping part-structure synoptic diagram of apparatus of the present invention
Figure 5 shows that afterburning part-structure synoptic diagram of beginning at the beginning of apparatus of the present invention
Figure 6 shows that apparatus of the present invention physical construction part synoptic diagram (three)
Figure 7 shows that the signal condition box composition frame chart of apparatus of the present invention
Figure 8 shows that the measurement mechanism software flow pattern
Figure 9 shows that test specimen initial deformation, starting force synoptic diagram.
Concrete label and symbol description are as follows among the figure:
Among Fig. 1
Represent adjustable positions
A, basic framework part B, test specimen clamping part
C, initial afterburning part D, vibrating sensing part
A, pilot hole 1 b, pilot hole 2c, pilot hole 3 d, pilot hole 4
1, base 2, bearing 3, force cell 4, web member
5, drag hook 6, test specimen 7, screw 8, gland
9, screw 10, screw 11, latch 12, bent plate
13, stop screw 14, support 15, bearing 16, line slideway
17, stop screw 18, screw 19, nut 20, line slideway
21, leading screw 22, nut 23, slide 24, stop screw
25, laser sensor 26, upper support seat 27, supporting seat 28, leading screw
29, bearing 30, screw 31, slide 32, baffle plate
33, screw 34, pressing plate 35, slide 36, set screw
37, torsion spring 38, baffle plate 39, screw 40, bearing pin
41, screw 42, signal condition box 43, computing machine 44, force signal amplifier
45, vibration signal amplifier 46, direct supply 47, data collecting card
Embodiment
Below in conjunction with drawings and Examples, technical scheme of the present invention is described further.
A kind of mechanical property of thin slab type wood materials rapid measurement device of the present invention, mainly form by two parts: physical construction part and data processing section, as shown in Figure 1.The major function of physical construction part is that clamping, adjustment, the initial displacement of test specimen applies, the sensing of starting force sensing, exciting and vibration signal.In the physical construction part, test specimen is by vertical clamping, upper end clamping, lower end freedom.Test specimen clamping part position is adjustable up and down, is suitable for measuring the test specimen of different length.The laser sensor adjustable positions is adapted to the original distortion of difference self of different test specimens.Drag hook position level is adjustable, is suitable for the test specimen free end is applied different initial displacements, can accurately set this initial displacement amount; After initial displacement applies, the size that force cell can the sensing starting force.In addition, after initial displacement applied, drag hook can discharge test specimen rapidly, realized the free vibration of test specimen.Force cell should be little range, precision force transducer, as the cantilevered force cell that can adopt space flight 701 research institutes to make, model BK-5D, range 3Kg, precision 0.05%.Laser sensor should be high accuracy displacement sensor, produces SUNX (looking god), model ANR1250 laser sensor+ANR5131 amplifier (controller) as adopting Japan.
The major function of data processing section is the conditioning of starting force signal and vibration signal, collection, the static buckling elastic modulus of handling, calculate test specimen, dynamic bending elastic modulus and vibration damping to be compared etc.Data processing section mainly is made up of signal condition box and computing machine.Force signal amplifier, laser sensor vibration signal amplifier, data collecting card etc. are arranged in the signal condition box.Data collecting card is general 16 data collecting card, as the NI-USB2008 data collecting card that can adopt America NI company to produce.Be useful on the special software of data acquisition, processing in the computing machine.Data acquisition, process software can adopt any computer programming language establishment, if adopt Labview virtual instrument language establishment meeting more convenient.
Measurement mechanism physical construction part
As shown in Figure 2, measurement mechanism physical construction is divided into four parts again: basic framework part A, test specimen clamping part B, initial afterburning portion C, vibrating sensing part D.Basic framework partly is the support body of entire measuring device.Test specimen clamping part can make an end of test specimen fix, and constitutes the crooked and vibration of test specimen semi-girder, prevents the test specimen run-off the straight and moves.Initial afterburning part can provide the initial displacement and the starting force of horizontal direction for effectively the test specimen free end, and can adopt the starting force signal by computing machine, calculates static MOE.The vibrating sensing part can be obtained the displacement vibration signal in the test specimen semi-girder vibration processes exactly and be sent to computing machine, and computing machine draws dynamic MOE by data analysis, processing.
As shown in Figure 3, the basic framework part A mainly is made up of base 1 and support 14; 14 on base 1 and support are fixedlyed connected by four screws 18; On base 1, be fixed with line slideway 20, on support 14, be fixed with line slideway 16; 1 of line slideway 20 and base, and line slideway 16 is connected by screw retention with 14 on support.
As shown in Figure 3 and Figure 4, test specimen clamping part B is made up of screw 7, gland 8, pressing plate 34, bearing 15, latch 11 (two), bent plate 12, slide 35 etc.Gland 8 is fixed on the bearing 15 by four screws 9, and on slide 35, slide 35 constitutes the line slideway group with guide rail 16 to bearing 15 by four screw retention.Rotary screw 7 to pressing plate 34 reinforcings, is pressed in test specimen 6 on the bearing 15.Slide 35 is fixedly linked by two screws 10 with bent plate 12, in the pilot hole that latch 11 inserts on the supports 14, realizes the location of upper-lower position of whole test specimen clamping part and fixing.The pilot hole (a, pilot hole 1, b, pilot hole 2, c, pilot hole 3, d, pilot hole 4) that four pairs of differing heights are arranged on the support 14, every pair of pilot hole is symmetrically distributed in line slideway 16 both sides (only having shown four pairs of pilot hole one side positions on Fig. 3).Every pair of pilot hole is realized " test specimen clamping part " upright position, i.e. the test specimen of a corresponding series length; The pilot hole of four pairs of differing heights is realized " test specimen clamping part " four upright positions, promptly corresponding to the test specimen series of four different lengths.As required, on differing heights, can increase pilot hole, even make continuous adjustable structure, to be suitable for the measurement demand of different length test specimen.
As Fig. 3 and shown in Figure 5, initial afterburning portion C is made up of slide 23, bearing 2, leading screw 21, force cell 3, web member 4, drag hook 5 etc.Drag hook 5 is connected with web member 4 by bearing pin 40, and drag hook 5 can rotate around bearing pin 40.Be with torsion spring 37 on the bearing pin 40, be used for to 5 one holding powers that make progress of drag hook, set screw 36 can keep drag hook 5 levels.23 of bearing 2 and slides are fixedly connected by four screws 41.Depress drag hook 5, hook test specimen 6 lower ends, force cell 3 can sensing go out initially (static state) power.Moving of drag hook 5 horizontal levels can realize by rotating threaded shaft 21.Baffle plate 38 is fixedly connected by two screws 39 and supporting seat 27.Nut 19 and nut 22 are used for locking leading screw 21 after the horizontal position adjustment of drag hook 5 is finished, keep the fixed distance of 27 of drag hook 5 and supporting seats constant.
As shown in Figure 6, vibrating sensing part D is made up of laser sensor 25, upper support seat 26, supporting seat 27, slide 31, leading screw 28, bearing 29 etc.Bearing 29 is fixed on the base 1 by four screws 30.Link to each other by screw retention between laser sensor 25, upper support seat 26, supporting seat 27, slide 31, four.Rotating threaded shaft 28 can be regulated laser sensor 25 horizontal levels.Baffle plate 32 is fixed together by two screws 33 and supporting seat 27.
The measurement mechanism data processing section
The data processing section of measurement mechanism mainly is made up of signal condition box 42 and computing machine 43.
The signal condition box
As shown in Figure 7, signal condition box 42 is made up of force signal amplifier 44, laser sensor vibration signal amplifier 45, data collecting card 47, direct current 46 etc.Force signal amplifier 44 and vibration signal amplifier 45 are supporting with selected force transducer and laser sensor respectively, generally require sensor manufacturer to provide with sensor is supporting.The output of two amplifiers is aanalogvoltage, and general requirement of maximum output valve is ± 5V.Data collecting card is general 16 data collecting card, as the NI-USB2008 data collecting card that can adopt America NI company to produce.Data collecting card 47 links to each other with two amplifiers respectively, connects with USB interface of computer by the usb data line simultaneously; Direct supply 46 links to each other with two amplifiers respectively, and the direct current supply of certain voltage is provided for two amplifiers.Direct current supply voltage is decided according to the requirement of selected sensor and amplifier, for example, the model BK-5D cantilevered force cell that space flight 701 research institutes make, the direct current supply voltage that needs is ± 12V; The ANR1250 laser sensor of Japan SUNX (looking god) and the combination of ANR5131 amplifier, the direct current supply voltage that needs is 12～24V.
Software flow
Be useful on the special software of signals collecting, analysis, processing in the computing machine.Software flow pattern as shown in Figure 8.This software can adopt any computer programming language establishment, if adopt Labview virtual instrument language establishment meeting more convenient.
Behind the clamping test specimen, open software.Setting measurement is storage directory and filename as a result, input test specimen basic parameter.The test specimen basic parameter comprises: test specimen numbering (title), specimen width b (mm), specimen thickness t (mm), test specimen total length L (mm), test specimen free end initial displacement Δ (mm), test specimen mass M (g).The automatic calculation testing piece jib-length of software l deducts clamping length 50mm for the test specimen total length L.Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, adjust the laser sensor horizontal level, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.The test specimen free end is applied the initial displacement Δ, click " beginning to measure " icon.Software collection starting force signal P calculates static MOE.Discharge the test specimen free end, the test specimen free vibration signal of software collection, demonstration laser sensor sensing; Analysis, processing signals: calculate (1) damping first natural frequency f
d, (2) calculate damping ratio, and (3) calculate undamped first natural frequency f, the dynamic MOE of (4) calculation testing piece.Storage, display result: static MOE, dynamic MOE, damping ratio etc.So far, finish a test process of a test specimen.
The quick measuring method of a kind of mechanical property of thin slab type wood materials of the present invention, concrete steps are as follows:
(1) accurately sets the initial displacement value.
The upright position of adjusting " test specimen clamping part B " is to a (pilot hole 1).Select a special processing, be of a size of 140 * 50 * 1.5mm (long * wide * thick), the sheet metal of any surface finish.Turn screw 7, with the sheet metal clamping to measurement mechanism.Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, by rotating threaded shaft 28, fine setting laser sensor 25 horizontal levels, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.Unclamp nut 19 and nut 22,, adjust the horizontal level of drag hook 5, the distance of preliminary surveying sheet metal left surface and drag hook 5 inside groove left margins by rotating threaded shaft 21.After the horizontal approximate location adjustment for the treatment of drag hook 5 is finished, fastening nut 19 and nut 22, locking leading screw 21 keeps the fixed distance of 27 of drag hook 5 and supporting seats motionless.Accurately measure the distance of sheet metal left surface and drag hook 5 inside groove left margins once more.Write down this distance value, this value is exactly in the mechanical property measuring process of back, the free-ended initial displacement value of test specimen Δ.
After once setting was finished, initial displacement value Δ promptly was fixed up, and the initial displacement of measuring any test specimen all is this value.When waiting to need to change initial displacement value Δ, just re-execute this step operation.
(2) the clamping test specimen 6.
According to different test specimen length, adjust the height of " test specimen clamping part ".Turn screw 7, with test specimen 6 clampings on measurement mechanism.
For simplifying test specimen 6 preliminary works, according to the specimen thickness difference, test specimen length is got four kinds of different sizes, but specimen width is 50mm.Concrete sample dimensions specification sees Table 1.This measurement mechanism can be measured maximum sample dimensions (long * wide * thick): 500 * 50 * 8.6mm.The test specimen clamping length is 50mm.
Table 1
(3) setting measurement storage directory and filename as a result, input test specimen basic parameter.
Open software, setting measurement is storage directory and filename as a result, input test specimen basic parameter.The test specimen basic parameter comprises: test specimen numbering (title), specimen width b (=50mm), specimen thickness t (mm), test specimen total length L (mm), test specimen free end initial displacement Δ (mm), test specimen mass M (g).The automatic calculation testing piece jib-length of software l deducts clamping length 50mm for the test specimen total length L.
(4) laser sensor displacement output zeroing.
After eliminating the test specimen clamping, himself influence of original distortion to measuring needs before formal the measurement laser sensor is aimed at the test specimen left surface zero point.Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, by rotating threaded shaft 28, fine setting laser sensor 25 horizontal levels, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.
(5) measure static MOE.
Manually the test specimen bottom is moved to right, and it is hung on the drag hook 5.Be equivalent to apply an initial displacement Δ to the test specimen free end.Click " beginning to measure " icon.Software collection initial displacement force signal P, acquisition time are 1 to several seconds; Calculate static MOE, show measurement result.The static MOE of test specimen measures, the calculating principle is as follows:
As shown in Figure 9, static modulus of elasticity
In the formula, P is initial static power (N), and Δ is load(ing) point displacement (m), and l is that semi-girder hangs (non-by clamping) partial-length (m), and b is specimen width (m), and t is specimen thickness (m).
(6) measure dynamic MOE.
After static MOE measurement result showed, drag hook 5 was removed downwards, discharged test specimen 6 free ends, test specimen free vibration.Laser sensor 25 sense vibration displacements, software is discerned vibration signal automatically, and gathers, shows the vibration displacement signal, and acquisition time is the several seconds, calculates dynamic MOE.Concrete signal analysis, contents processing comprise: calculate (1) damping first natural frequency f
d, (2) calculate dampingratio, and (3) calculate undamped first natural frequency f, the dynamic MOE of (4) calculation testing piece.Concrete signal is analyzed, handling principle is as follows.
Damping first natural frequency f is arranged
d, the vibration signal processing that collects is obtained by fast fourier transformation algorithm.Damping ratio
In the formula, δ is that free vibration amplitude logarithm reduces; Its calculating formula is
Wherein, A
1For on the vibration damping squiggle, the 1st amplitude of choosing; A
nFor on the vibration damping squiggle, n the amplitude of choosing.Damping first natural frequency f is being arranged
dBehind dampingratio, the computing formula of undamped first natural frequency is
At last, the dynamic modulus of elasticity
In the formula, ρ is density (Kg/m
3), f is undamped first natural frequency (Hz), and l is that semi-girder hangs (non-by clamping) partial-length (m), and t is specimen thickness (m).And test specimen density
In the formula, M is test specimen quality (kg), and b is specimen width (m), and L is test specimen total length (m).
(7) storage, demonstration measurement result.
Software is stored the test specimen measurement result automatically, comprising: test specimen is numbered (title), static buckling elastic modulus (static MOE), dynamic bending elastic modulus (dynamically MOE), vibration damping ratio, damping first natural frequency f is arranged
dWith undamped first natural frequency f.Unless reset storage directory and filename, otherwise new measurement result continues to write end-of-file (EOF) place, front.
Software shows three measurement results of test specimen automatically, comprising: static MOE (when being shown in (5) EOS earlier), dynamic MOE and vibration damping ratio.
So far, a measuring process finishes.As not changing initial displacement value Δ, next measuring process begins to get final product from step (2).If test specimen itself exists certain bending or torsional deformation, or the mechanical property distribution is inconsistent on the test specimen length direction, and then change can appear in measurement result.Recommendation is at a test specimen, and about carrying out, pros and cons measures for four times, the mean value of getting four measurement results then is as the test specimen elastic mould value.If four measurement result difference of a plurality of test specimens of random sampling are very little in batch of test specimen, can only measure once other test specimen of this batch.
Embodiment one:
Below in conjunction with the one-shot measurement of a test specimen, the embodiment of measurement mechanism and measuring process is described.The test specimen material is medium-density plate (MDF), and sample dimensions (long * wide * thick) is: 340 * 50 * 3.7mm.The special software that is used for signals collecting, analysis, processing in the computing machine adopts the establishment of Labview virtual instrument language.
(1) accurately sets the initial displacement value.
The upright position of adjusting " test specimen clamping part " is to " pilot hole 1 ".Select a special processing, be of a size of 140 * 50 * 1.5mm (long * wide * thick), the sheet metal of any surface finish, clamping is to measurement mechanism.Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, by rotating threaded shaft 28, fine setting laser sensor 25 horizontal levels, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.Unclamp nut 19 and nut 22,, adjust the horizontal level of drag hook 5, the distance of preliminary surveying sheet metal left surface and drag hook 5 inside groove left margins by rotating threaded shaft 21.After the horizontal approximate location adjustment for the treatment of drag hook 5 is finished, fastening nut 19 and nut 22, locking leading screw 21 keeps the fixed distance of 27 of drag hook 5 and supporting seats motionless.The distance of accurately measuring sheet metal left surface and drag hook 5 inside groove left margins once more is 12mm.This value is exactly in the back actual measurement process, test specimen free end initial displacement value Δ=12mm.
(2) clamping test specimen.
The upright position of adjusting " test specimen clamping part " is to " pilot hole 3 ".Turn screw 7, with the test specimen clamping on measurement mechanism.The test specimen clamping length is 50mm.
(3) input test specimen basic parameter.
Open software, setting measurement is storage directory and filename as a result, input test specimen basic parameter.The test specimen basic parameter of input comprises: test specimen numbering=MDF3.7-1, specimen width b=50mm, specimen thickness t=3.7mm, test specimen total length L=340mm, test specimen free end initial displacement Δ=50mm, test specimen mass M=48.5g.The automatic calculation testing piece jib-length of software l is 290mm.
(4) laser sensor displacement output zeroing.
Click and " begin to return to zero " icon on the software interface.Software collection, show the displacement signal of laser sensor output, by rotating threaded shaft 28, fine setting laser sensor 25 horizontal levels, to its output voltage be 0.Click and " stop to return to zero " icon on the software interface.
(5) measure static MOE.
Manually the test specimen bottom is moved to right, and it is hung on the drag hook 5.Be equivalent to apply an initial displacement Δ=12mm to the test specimen free end.Click " beginning to measure " icon.Software collection initial displacement force signal P, acquisition time was 1 second; Calculate static MOE=3.55GPa.
(6) measure dynamic MOE.
(7) storage, demonstration measurement result.
Software is stored the test specimen measurement result automatically, comprising: test specimen numbering (title)=MDF3.7-1, static MOE=3.55GPa, dynamically MOE=3.75GPa, vibration damping than ζ=0.075, damping first natural frequency f is arranged
d=15.891Hz and undamped first natural frequency f=15.892Hz.
Software shows three measurement results of test specimen automatically.Comprise: static MOE=3.55GPa, dynamic MOE=3.75GPa and vibration damping are than ζ=0.075.
Claims (2)
1. mechanical property of thin slab type wood materials rapid measurement device, it is characterized in that: this device is made up of two parts: physical construction part and data processing section,
Described physical construction part is divided into four parts again: basic framework part (A), test specimen clamping part (B), initial afterburning part (C), vibrating sensing part (D);
Basic framework part (A) is made up of base (1) and support (14); Base (1) is fixedlyed connected with support (14); On base (1), be fixed with horizontal linear guide rail (20), on support (14), be fixed with vertical line guide rail (16); Between horizontal linear guide rail (20) and base (1), and be connected by screw retention between vertical line guide rail (16) and support (14);
Test specimen clamping part (B) is made up of screw (7), gland (8), pressing plate (34), first bearing (15), latch (11), bent plate (12), slide (35); Gland (8) is fixed on first bearing (15), and first bearing (15) is fixed on the slide (35), and slide (35) constitutes the line slideway group with vertical line guide rail (16); Slide (35) and bent plate (12) are fixedly linked, and latch (11) inserts in the pilot hole on the support (14), realize the location of upper-lower position of whole test specimen clamping part and fixing; The pilot hole that four pairs of differing heights are arranged on the support (14), every pair of pilot hole is symmetrically distributed in vertical line guide rail (16) both sides;
Initial afterburning part (C) is made up of slide (23), second bearing (2), right rotation leading screw (21), force cell (3), web member (4), drag hook (5); Drag hook (5) is connected with web member (4) by bearing pin (40), and drag hook (5) can rotate around bearing pin (40); Be with torsion spring (37) on the bearing pin (40), be used for to (5) holding powers that make progress of drag hook, set screw (36) can keep drag hook (5) level; Second bearing (2) is fixedly connected with slide (23); Moving of drag hook (5) horizontal level can realize by rotation right rotation leading screw (21); Baffle plate (38) is fixedly connected with supporting seat (27); Left side nut (19) and right nut (22) are used for locking right rotation leading screw (21) after the horizontal position adjustment of drag hook (5) is finished, keep the fixed distance between drag hook (5) and supporting seat (27) constant;
Vibrating sensing part (D) is made up of laser sensor (25), upper support seat (26), supporting seat (27), slide (31), anticlockwise leading screw (28), the 3rd bearing (29); The 3rd bearing (29) is fixed on the base (1); Laser sensor (25), upper support seat (26), supporting seat (27), slide (31) link to each other by screw retention between four; Anticlockwise leading screw (28) is regulated laser sensor (25) horizontal level; Baffle plate (32) is fixed together with supporting seat (27);
Described data processing section comprises signal condition box (42) and computing machine (43);
Signal condition box (42) is made up of force signal amplifier (44), laser sensor vibration signal amplifier (45), data collecting card (47), direct supply (46); Data collecting card links to each other with two amplifiers respectively, connects with USB interface of computer by the usb data line simultaneously; Direct supply links to each other with two amplifiers respectively, and the direct current supply of certain voltage is provided for two amplifiers.
2. the quick measuring method of mechanical property of thin slab type wood materials of utilizing the described measurement mechanism of claim 1 is characterized in that: specifically comprise the steps:
(1) accurately sets the initial displacement value
Adjust the upright position of " test specimen clamping part B ", select the sheet metal of an any surface finish, with the sheet metal clamping to measurement mechanism; Fine setting laser sensor (25) horizontal level, to its output voltage be 0; Adjust the horizontal level of drag hook (5), the distance of preliminary surveying sheet metal left surface and drag hook (5) inside groove left margin; Keep the fixed distance between drag hook (5) and supporting seat (27) motionless; Accurately measure the distance of sheet metal left surface and drag hook (5) inside groove left margin once more; This distance value is exactly the free-ended initial displacement value of a test specimen Δ;
(2) clamping test specimen
According to different test specimen length, adjust the height of " test specimen clamping part B ", with test specimen (6) clamping on measurement mechanism;
(3) setting measurement storage directory and filename as a result, input test specimen basic parameter
Open the special software that is used for data acquisition, processing, setting measurement is storage directory and filename as a result, input test specimen basic parameter; The test specimen basic parameter comprises: test specimen numbering, specimen width b, specimen thickness t, test specimen total length L, test specimen free end initial displacement Δ, test specimen mass M;
(4) laser sensor displacement output zeroing
After eliminating the test specimen clamping, himself influence of original distortion to measuring needs before formal the measurement laser sensor is aimed at the test specimen left surface zero point; Click and " begin to return to zero " icon on the software interface; Software collection, show the displacement signal of laser sensor output, by anticlockwise leading screw (28), fine setting laser sensor (25) horizontal level, to its output voltage be 0; Click and " stop to return to zero " icon on the software interface;
(5) measure the static buckling elastic modulus
Manually the test specimen bottom is moved to right, and it is hung on the drag hook 5, be equivalent to apply an initial displacement Δ to the test specimen free end; Click " beginning to measure " icon; Software collection initial displacement force signal P, acquisition time are 1 to several seconds; The static buckling elastic modulus shows measurement result;
Test specimen static buckling elastic modulus computing method are as follows:
The static buckling elastic modulus
In the formula, P is initial static power (N), and Δ is a test specimen free end initial displacement (m), and l is that semi-girder hangs partial-length (m), and b is specimen width (m), and t is specimen thickness (m);
(6) measure the dynamic bending elastic modulus
After static buckling elastic modulus measurement result showed, drag hook (5) was removed downwards, discharged test specimen (6) free end, test specimen free vibration; Laser sensor (25) sense vibration displacement, software is discerned vibration signal automatically, and gathers, shows the vibration displacement signal, and acquisition time is the several seconds, calculates the dynamic bending elastic modulus; Concrete signal analysis, contents processing comprise: 1. calculating has damping first natural frequency f
d2. calculate dampingratio; 3. calculate undamped first natural frequency f; 4. calculation testing piece dynamic bending elastic modulus;
Concrete signal analysis, processing and static buckling elastic modulus computing method are as follows:
Damping first natural frequency f is arranged
d, the vibration signal processing that collects is obtained by fast fourier transformation algorithm; Damping ratio
In the formula, δ is that free vibration amplitude logarithm reduces; Its calculating formula is
Wherein, A
1For on the vibration damping squiggle, the 1st amplitude of choosing; A
nFor on the vibration damping squiggle, n the amplitude of choosing; Damping first natural frequency f is being arranged
dBehind dampingratio, the computing formula of undamped first natural frequency is
At last, dynamic bending elastic modulus
In the formula, ρ is density (Kg/m
3), f is undamped first natural frequency (Hz), and l is that semi-girder hangs partial-length (m), and t is specimen thickness (m); And test specimen density
In the formula, M is test specimen quality (kg), and b is specimen width (m), and L is test specimen total length (m);
(7) storage, demonstration measurement result
Software is stored the test specimen measurement result automatically, comprising: test specimen numbering, static buckling elastic modulus, dynamic bending elastic modulus, vibration damping compare, have damping first natural frequency f
dWith undamped first natural frequency f;
So far, a measuring process finishes.
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| CN102607695B (en) * | 2012-02-16 | 2014-04-30 | 中国人民解放军重庆通信学院 | Method for calculating natural frequency of honeycomb sandwich plate |
| CN106679951B (en) * | 2016-12-22 | 2019-03-26 | 海盐海马五金有限公司 | A kind of finished product support product test method |
| CN107328663B (en) * | 2017-06-30 | 2020-02-07 | 中国西电电气股份有限公司 | Temperature environment test box, sealing structure and method for thermal mechanical performance test |
| CN114322435A (en) * | 2021-12-14 | 2022-04-12 | 澳柯玛股份有限公司 | Adjustable shelf support for refrigerator |
| CN117169025B (en) * | 2023-11-02 | 2024-02-09 | 天水华洋电子科技股份有限公司 | Integrated circuit lead frame process detection technology |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2179972Y (en) * | 1993-12-04 | 1994-10-19 | 北京市房地产科学技术研究所 | Timber strength tester |
| US5503024A (en) * | 1994-12-22 | 1996-04-02 | Metriguard Inc. | Apparatus for testing lumber stiffness |
| CN201344893Y (en) * | 2009-02-20 | 2009-11-11 | 北京林业大学 | Device for quickly measuring mechanical property of thin-plate wood material |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2179972Y (en) * | 1993-12-04 | 1994-10-19 | 北京市房地产科学技术研究所 | Timber strength tester |
| US5503024A (en) * | 1994-12-22 | 1996-04-02 | Metriguard Inc. | Apparatus for testing lumber stiffness |
| CN201344893Y (en) * | 2009-02-20 | 2009-11-11 | 北京林业大学 | Device for quickly measuring mechanical property of thin-plate wood material |
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