CN101603820B - Real-time detection system for wood microstructure characteristic changes - Google Patents
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- CN101603820B CN101603820B CN 200910089771 CN200910089771A CN101603820B CN 101603820 B CN101603820 B CN 101603820B CN 200910089771 CN200910089771 CN 200910089771 CN 200910089771 A CN200910089771 A CN 200910089771A CN 101603820 B CN101603820 B CN 101603820B
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Abstract
The invention discloses a real-time detection system for wood microstructure characteristic changes, which comprises a loading unit, a microscopic unit, an image acquisition unit and an image processing unit, wherein the loading unit is used to stretch, compress, bend, twist or cut to-be-detected wood; the microscopic unit is used to magnify a to-be-detected area of the wood; the image acquisition unit is used to acquire surface image information of the area magnified through the microscopic unit; and the image processing unit is used to receive image information acquired by the image acquisition unit, calculate and obtain the micro-area strain information and the real-time microstructure change results of the to-be-detected wood. The system can measure micro-area tissue and cell strain to realize micro-area deformation quantization, and can monitor micro-area defects.
Description
Technical field
The present invention relates to the real-time detecting system of the compression of a kind of timber and composite wooden material or mechanical strength performance such as stretching and deformation microstructure characteristics.
Background technology
Timber and composite wooden material are in production and processing and use, inevitably can run into mechanical behaviors such as compression or stretching, detecting for the mechanical property of material is to guarantee subsequent product quality and the key of rationally using thereof, but this mechanical behavior is all still unintelligible to material monolithic Effect on Performance situation to the performance of material or product and micromechanism influence and microstructure characteristic.
For present detection means, mainly detect based on single macro-mechanical property.This detection means has many defectives and shortcoming:
1, only judging the performance of wood materials with the macromechanics behavior, is the deficiency that the performance of material own is grasped;
2, only can understand the result of mechanics of materials behavior, and not know to form the reason of this mechanical behavior;
3, testing process can not take in influence factors such as the temperature of measured material, water percentage;
4, the strain that obtains of testing process is the mean strain of material monolithic, can not embody the strained situation of material different tissues structure; Can not reaction wood each several part structure and integrated stress, strain relation;
5, for this heterogeneity material with anisotropic of timber, the strain result who obtains is single, can not truly reflect the ess-strain result of each institutional framework of timber;
6, after detection finishes, the bounce situations of measured material can not be in time obtained, the unrelieved stress of measured material can not be analyzed.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of real-time detection system for wood microstructure characteristic changes, can online in real time measures the microstructure characteristic and the mechanical property of material deformation.
In order to address the above problem, the invention provides a kind of real-time detection system for wood microstructure characteristic changes, comprising: loading unit, micro-unit, image acquisition units and graphics processing unit, wherein,
Described loading unit is used to compress, stretches, crooked, reverse or shear timber to be detected;
Described micro-unit is used to amplify the zone to be measured of timber;
Described image acquisition units is used to gather the surface image information through the zone after the described micro-unit amplification;
Described graphics processing unit is used to receive the image information that described image acquisition units is gathered, and calculates and obtain the microcell strain information and the real-time microstructure change result of described timber to be detected.
Preferably, also comprise automatic focusing control unit, be used for adjusting focal length automatically in the described micro-unit of loading procedure control at described timber to be detected.
Preferably, described micro-unit is an optical microscope.
Preferably, described image acquisition units is camera and/or video camera.
Preferably, also comprise conducting-heat elements, be used for the temperature at the described timber to be detected of loading procedure control, described heat conduction briquetting is regulated temperature by a temperature-controlled box.
Preferably, also comprise the water percentage control assembly, be used for the water percentage at the described timber to be detected of loading procedure control, described water percentage control assembly is regulated water percentage with a casing.
The present invention has following advantage:
1, the present invention combines continuous mechanical test process with the dynamic structural change of timber, can reflect the relation between the variation of timber or composite wooden material mechanical property and microstructure characteristic in real time.
2, the present invention can set up two-dimentional relation between the two arbitrarily, and reach real real-time " prison " and " survey " synchronous fully between mechanics loading procedure, material property data result, microstructure change image and the time data point.
3, the present invention can measure the tissue and the cell strain of microcell, realizes that the microcell distortion quantizes; Can monitor the microcell defective.
4, the present invention can test the relation between timber or composite wooden material mechanical property and the microstructure change, can quantize simultaneously distortion of materials bounce situations behind the mechanics loading procedure.
5, the present invention extends to dynamic mechanical test in low temperature or the high temperature category, can set up the relation between the variation of temperature and mechanical property and wood microstructure.
6, the present invention extends to dynamic mechanical test in the different water cut rate category, can set up the relation between the variation of water percentage and mechanical property and wood microstructure.
7, the present invention has adopted automatic focusing system, can effectively improve the image acquisition precision, shortens image acquisition at interval.
8, the present invention can realize computer full-automation operation, avoids artificial control and each system to separate the error that control is easily caused.
9, resulting stress-strain curve of the present invention and microscale deformation mechanism can be caught the key of wood materials and composite wooden material ductility and intensity.
10, of the present invention applied widely, compression loaded load wide ranges such as (or stretchings), the sample that is suitable for all kinds/shape and size is studied, and comprises solid wood material, composite wooden material, other timber derived products etc.
Description of drawings
Fig. 1 is a structural representation of the present invention;
Fig. 2 is the synoptic diagram of the tested timber of the present invention.
Embodiment
As shown in Figure 1, the present invention includes: loading unit 1, temperature-controlled box 3, sensor 4, computing machine 5 (being graphics processing unit), optical microscope 6, digital camera 7 and video camera 8.Loading unit 1 be used for to tested timber 2 compress, stretch, crooked, reverse or mechanical behavior such as shearing.Temperature-controlled box 3 links to each other with computing machine 5 with loading unit 1, is used to control the temperature (theoretical category-140～600 ℃) of timber to be checked.Optical microscope 6 links to each other with digital camera 7, video camera 8 and computing machine 5, is used for the collection of the tested wood surface deformation map of pressurized or tension picture.3 cover sensors 4, covers link to each other with drilling depth system 12 in the loading unit 1, are used to measure the whole displacement of tested timber 2; One cover links to each other with Load Control (pressure control or control are drawn) system 13, measures load value (pressure or pulling force etc.); One cover links to each other with conducting-heat elements (as the heat conduction briquetting or the folder etc. that stretches) 11, is used for the temperature that temperature-controlled box is controlled tested timber 2.Digital camera 7 all links to each other with computing machine 5 with video camera 8, is used for the data acquisition of stress and deformation map picture.Computing machine 5 is used to receive the detection data and the view data of drilling depth system 12, load control system 13, digital camera 7 and video camera 8, and obtain the strain information and the springback capacity of described tested timber by computed in software according to the displacement data result, obtain stress-strain diagram and the real-time microstructure change result of tested timber simultaneously.
As shown in Figure 1, optical microscope 6 can be normal optical three order biological microscopes, form by spotlighting system 61, eyepiece 62, object lens 63, objective table 64 and focus adjusting mechanism, and link to each other with video camera 8, be used for the collection of stressed wood surface deformation map picture with digital camera 7; Wherein, focus adjusting mechanism is an autofocus system 65, is arranged on the optical microscope, and an end connects computing machine 5, is used to control the focal adjustments of optical microphotograph endoscope objective lens 63, by the interval time of computing machine 5 control focusing.
As shown in Figure 1, loading unit 1 is made up of conducting-heat elements 11, drilling depth system 12, load control system 13, cooling system 14, is used for the compression or the timber 2 to be checked that stretches; Wherein, cooling system 14 is divided into water-cooled and cold two covers of nitrogen, water-cooled is used for loading unit conducting-heat elements 11 and load control system 13 by high temperature cool to room temperature state, nitrogen colod-application in loading unit conducting-heat elements 11 drop to the state of low temperature by room temperature, thereby the temperature of control measured material.
The present invention is owing to adopt autofocus system 65 to regulate the focal lengths of the object lens 63 of optical microscopes 6 in real time automatically, thereby can effectively improve the image acquisition precision, shortens image acquisition at interval.In addition, the present invention is owing to adopt video camera 8, and overall dimensions such as integral thickness that can the stressed tested timber of Real Time Observation or length change, thereby calculates the springback capacity and the rebound degree of stressed back any time measured material by the computing machine 5 that is attached thereto.Among the present invention, focusing can be adopted conventional automatic focusing method automatically.
Concrete determination step is as follows, as shown in Figure 1:
1) at first measures the radial dimension L of measured material 2
R, tangential size L
T, longitudinal size L
L(as shown in Figure 2), be input in the computing machine 5, as the raw data of this measured material;
2) measured material 2 is positioned on the loading unit 1, in computing machine 5, sets parameters such as maximum weighted (compression or stretching etc.) load, maximum compression rate (or extensibility, amount of deflection etc.), loading velocity;
3) select the suitable object lens 63 of multiple on optical microscope 6, adjust to reasonable focal length with autofocus system 65, it is complete to make measured material 2 surfaces be clear picture in digital camera 7 and video camera 8; In computing machine 5, set the digital camera photo opporunity at interval, as 5sec, 10sec etc.; Set the automatic focusing time interval of autofocus system 65 simultaneously, the photo opporunity of setting with digital camera is identical at interval, and automatic focusing finishes before guaranteeing to take pictures at every turn;
4) the measured material finishing temperature is set in measured material intensification or cooling if desired earlier in computing machine 5, and needs to open temperature-controlled box 3 switches in mensuration preceding ten minutes (shortest time) of beginning, makes tested timber 2 progressively heat up (or cooling) to design temperature;
5) while start-up loading unit 1, digital camera 7, video camera 8, automatic focusing system 65 begin test;
6) computing machine 5 obtains the size of real-time loaded load δ by sensor 4 control load control system 13; Obtain the real-time displacement data of measured material by drilling depth system 12, computing machine 5 calculates the real-time strain stress of measured material
BObtain measured material surface real-time deformation image clearly by digital camera 7 and video camera 8; Above data are sent in the computing machine 5 in real time until end of test (EOT);
7) after the end of test (EOT), rapidly measured material is taken off from loading unit 1, lie in and aim at the object lens center on the optical microscope objective table, continue to take the stressed whole measurand in back that finishes continuously to a couple of days with video camera 8, the image that video camera 8 is taken is input in the computing machine 5 in real time;
8) view data passed back according to digital camera 7 of computing machine 5 utilizes two kinds of methods by the image calculation strain to calculate the real-time X-axis strain stress of measured material
x, the Y-axis strain stress
y, whole strain stress
A, and the real-time strain stress that it and the displacement data that obtains by drilling depth system 12 are calculated
BContrast;
9) view data passed back according to video camera 8 of computing machine 5 calculates any one thickness (or length) L constantly of the stressed back of measurand
k, utilize formula to calculate stressed back measured material at any one springback capacity R constantly, R=L
k-L
0And rebound degree R
r, R
r(%)=(L
k-L
0) * 100/L
0Wherein, k=0,1,2 ..., k, the moment that " 0 " representative test has just finished.
By the said determination step, just can access the stress-strain curve of material in whole loading procedure, obtain compression (or stretching, bending etc.) the mechanical property characterization result of material, for example, elastic deformation stage, plastic yield stage, yield point, failure stage, and corresponding with it material microstructure image.
In addition, the present invention can also be provided with the water percentage control assembly, is used for the water percentage at the described timber to be detected of loading procedure control, and the water percentage control assembly can be by regulating water percentage with a casing.The present invention can set up the relation between the variation of water percentage and mechanical property and wood microstructure by dynamic mechanical test being extended in the different water cut rate category.
In the said determination step, loading unit 1, temperature-controlled box 3, digital camera 7, video camera 8, autofocus system 65 are by computing machine 5 unified controls, run-in synchronism, data that each mechanism obtains also send back in the computing machine 5 in real time, like this, each mechanism's gained load, temperature, strain and view data all can be that object of reference is set up two-dimentional relation the time more than.
In addition, the present invention has comprised three kinds and has measured strain process, calculates mean strain ε thereby 1. utilize differential pick-up to measure average deformation
BMethod, 2. by each component units of image measurement (be cell in the timber) X-axis deformation and Y-axis deformation, and then calculate measured material integral body X-axis and Y-axis mean strain ε
x, ε
yMethod, the 3. variation of making a gesture of measuring by the tissue of image measurement component units entity part (entity part in the timber is a cell membrane), thus calculate measured material ensemble average strain stress
AMethod.Three kinds of method gained data can compare and complementation.
In sum; being preferred embodiment of the present invention only below, is not to be used to limit protection scope of the present invention, therefore; all any modifications of being done within the spirit and principles in the present invention, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (6)
1. a real-time detection system for wood microstructure characteristic changes is characterized in that, comprising: loading unit, micro-unit, image acquisition units and graphics processing unit, wherein,
Described loading unit is used to compress, stretches, crooked, reverse or shear timber to be detected;
Described micro-unit is used to amplify the zone to be measured of timber;
Described image acquisition units is used to gather the surface image information through the zone after the described micro-unit amplification;
Described graphics processing unit is used to receive the image information that described image acquisition units is gathered, and calculates and obtain the microcell strain information and the real-time microstructure change result of described timber to be detected.
2. the system as claimed in claim 1 is characterized in that, also comprises automatic focusing control unit, is used for adjusting focal length at described timber to be detected automatically in stretching or the described micro-unit of compression process control.
3. the system as claimed in claim 1 is characterized in that, described micro-unit is an optical microscope.
4. the system as claimed in claim 1 is characterized in that, described image acquisition units is camera and/or video camera.
5. as the arbitrary described system of claim 1 to 4, it is characterized in that, also comprise conducting-heat elements, be used for the temperature at the described timber to be detected of record process control, described conducting-heat elements is regulated temperature by a temperature-controlled box.
6. system as claimed in claim 5 is characterized in that, also comprises the water percentage control assembly, is used for the water percentage at the described timber to be detected of loading procedure control, and described water percentage control assembly is regulated water percentage with a casing.
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| CN 200910089771 CN101603820B (en) | 2009-07-23 | 2009-07-23 | Real-time detection system for wood microstructure characteristic changes |
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| CN 200910089771 CN101603820B (en) | 2009-07-23 | 2009-07-23 | Real-time detection system for wood microstructure characteristic changes |
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| CN101603820B true CN101603820B (en) | 2010-12-01 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103592182B (en) * | 2013-11-11 | 2015-09-30 | 华南农业大学 | With carrying lower microstructure realtime graphic observation acquisition platform and method |
| CN106568648B (en) * | 2016-11-01 | 2019-06-25 | 中国石油大学(北京) | A kind of characteristic of material mechanics meso-scale experimental method |
| CN108871203B (en) * | 2018-07-10 | 2020-04-07 | 广东中科奥辉科技有限公司 | High-efficient AOI check out test set with automatic identification and fixed function |
| CN109870367B (en) * | 2019-03-04 | 2020-04-03 | 燕山大学 | Determination method and test device for bending springback parameter of high-strength aluminum alloy plate |
| CN110082209A (en) * | 2019-05-14 | 2019-08-02 | 南京林业大学 | A kind of controllable timber micro mechanics measuring device of moisture content and its measurement method |
| CN110702513B (en) * | 2019-10-15 | 2021-06-18 | 吉林大学 | Test measurement method for large-strain-range hardening curve of metal bar |
| CN111272568B (en) * | 2020-01-22 | 2022-08-19 | 中国人民解放军国防科技大学 | Device and method for measuring stretching-shearing and stretching-twisting coupling effects |
| CN112485254A (en) * | 2020-11-23 | 2021-03-12 | 北京林业大学 | Water content detection system for effluent wooden cultural relics based on digital image correlation |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2347167Y (en) * | 1998-11-04 | 1999-11-03 | 中国科学院广州能源研究所 | Wood water content rate measurer |
| CN1645130A (en) * | 2005-01-11 | 2005-07-27 | 胡英成 | Woods and wooden composite material shearing modulus non destructive checkers |
| CN1800838A (en) * | 2004-12-30 | 2006-07-12 | 戚大伟 | Non-destructive test device for wood |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2347167Y (en) * | 1998-11-04 | 1999-11-03 | 中国科学院广州能源研究所 | Wood water content rate measurer |
| CN1800838A (en) * | 2004-12-30 | 2006-07-12 | 戚大伟 | Non-destructive test device for wood |
| CN1645130A (en) * | 2005-01-11 | 2005-07-27 | 胡英成 | Woods and wooden composite material shearing modulus non destructive checkers |
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