CN110940728B - Nondestructive detection method for tree defects - Google Patents
Nondestructive detection method for tree defects Download PDFInfo
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- CN110940728B CN110940728B CN201911300377.8A CN201911300377A CN110940728B CN 110940728 B CN110940728 B CN 110940728B CN 201911300377 A CN201911300377 A CN 201911300377A CN 110940728 B CN110940728 B CN 110940728B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
- G01N29/07—Analysing solids by measuring propagation velocity or propagation time of acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/4445—Classification of defects
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/01—Indexing codes associated with the measuring variable
- G01N2291/011—Velocity or travel time
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0238—Wood
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/028—Material parameters
- G01N2291/0289—Internal structure, e.g. defects, grain size, texture
Abstract
The invention provides a nondestructive detection method and a nondestructive detection device for tree defects. Selecting a tree to be detected, and selecting a section of the tree to be tested; selecting at least two groups of ultrasonic transmission paths with different ultrasonic transmission directions on the section, wherein each group of paths consists of a plurality of paths, and each path is provided with an ultrasonic probe; acquiring the ultrasonic transmission speed on each path by the nonmetal ultrasonic flaw detector; correcting the ultrasonic transmission speed on each path; judging an abnormal path; drawing a transmission speed grid map of the whole tree section according to the ultrasonic transmission speed on each path, determining the defect position through computer data processing and the grid map of the transmission speed, and making a defect schematic diagram. The method can be used for rapidly, accurately and nondestructively detecting whether the interior of the tree has the defects or not, and can be used for rapidly positioning the positions of the defects to obtain a defect schematic diagram.
Description
Technical Field
The invention relates to the field of detection, in particular to a nondestructive detection method and a nondestructive detection device for tree defects.
Background
Since ancient famous trees, valuable woods and the like are expensive, the evaluation of the value of the ancient famous trees, the valuable woods and the like is very important, and the important point for evaluating the value of the ancient famous trees, the valuable woods and the like is whether the interior of the trees or the woods is damaged or not. At present, a plurality of tree nondestructive flaw detectors in the market mainly install a plurality of sensors on the section of wood to be detected, and detect flaws by combining stress parameters, but the accuracy of flaw detection effect is still to be improved.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a nondestructive detection method and a nondestructive detection device for tree defects.
In order to achieve the above object, the present invention provides a nondestructive testing method for tree defects, comprising the following steps:
s1, selecting a tree to be detected, and selecting a section of the tree to be tested;
s2, selecting at least two groups of ultrasonic transmission paths with different ultrasonic transmission directions on the cross section, wherein each group of paths consists of a plurality of paths, and each path is provided with an ultrasonic probe;
s3, acquiring the ultrasonic transmission speed on each path by the nonmetal ultrasonic flaw detector;
s4, correcting the ultrasonic transmission speed on each path, the correction formula is:
V＝VN/(-0.2θ2+1)；
where V is the corrected ultrasonic transmission speed, VNThe ultrasonic transmission speed on the Nth path measured by the ultrasonic flaw detector is N which is a positive integer not greater than the total number of the paths, and theta is an included angle between the direction of the ultrasonic transmission path and the ultrasonic emission direction of the ultrasonic probe;
and S5, processing the ultrasonic transmission speed after each path is corrected, and defining the transmission path as an abnormal path when the following formula is satisfied:
s6, drawing a transmission speed grid chart of the whole tree section according to the ultrasonic transmission speed on each path, marking the abnormal path and the normal path with different marks in the grid chart, determining the defect position through the grid chart of the computer data processing and the transmission speed, and making a defect schematic diagram.
The method can be used for rapidly, accurately and nondestructively detecting whether the interior of the tree has the defects or not, and can be used for rapidly positioning the positions of the defects to obtain a defect schematic diagram.
When the number of the ultrasonic wave groups is two, the two groups of ultrasonic wave transmission paths are mutually vertical, the cross section to be measured is divided into (m +1) (n +1) squares, m is the number of paths contained by one group of ultrasonic waves, and n is the number of paths contained by the other group of ultrasonic waves.
The step S6 includes the following steps:
s61, marking the abnormal path and the normal path determined in the step S5 by different marks;
s62, in the transmission speed grid diagram, each grid is composed of four line segments:
when all the line segments in the grid are marks of the normal path, the grid area is considered to be in a non-defective position;
when one or two parallel line segments in the grid are the marks of the abnormal path, the defect position is on the straight line where the corresponding line segment is located, but the grid is not located at the defect position;
when two mutually perpendicular line segments or three line segments in the grid are marks of abnormal paths, the grid part is positioned at a defect;
when four line segments in the grid are the labels of the abnormal path, the grid is completely at the defect.
Filling and rounding the defective grid obtained in the step S62, and marking according to the severity of the defect to obtain a cross-section defect schematic diagram;
wherein the severity of the defect level is determined by the ratio of the transmission speed to the average speed
It is determined that,
severity of the defect and
in direct proportion. The method can detect whether the tree has defects more quickly and accurately, and can quickly and intuitively position the defects.
The invention also provides a tree nondestructive testing device based on the tree defect nondestructive testing method, which comprises an ultrasonic probe, a nonmetal ultrasonic flaw detector connected with the ultrasonic probe and a computer connected with the nonmetal ultrasonic flaw detector; the ultrasonic probe is arranged according to the tree defect nondestructive testing method, and the computer is used for detecting the tree defects according to the tree defect nondestructive testing method.
The invention has the beneficial effects that: the invention adopts the nonmetal ultrasonic flaw detector to detect the tree defects, has little damage to the trees, basically achieves nondestructive detection, and has the advantages of high detection speed, simple detection method, accurate detection result and high defect positioning accuracy.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a simulated perspective view of the present invention;
FIG. 3 is a schematic diagram of the present invention;
FIG. 4 is a view of a transmission speed correction;
fig. 5 is a diagram showing an ultrasonic transmission path distribution of a surface to be tested.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
In the description of the present invention, unless otherwise specified and limited, it is to be noted that the terms "mounted," "connected," and "connected" are to be interpreted broadly, and may be, for example, a mechanical connection or an electrical connection, a communication between two elements, a direct connection, or an indirect connection via an intermediate medium, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.
As shown in FIG. 1, the present invention provides a nondestructive testing method for tree defects, comprising the following steps:
s1, selecting a tree to be detected, and selecting a section of the tree to be tested, wherein the section can be a cross section or a longitudinal section.
And S2, selecting at least two groups of ultrasonic transmission paths with different ultrasonic transmission directions on the cross section, wherein each group of paths consists of a plurality of paths, and each path is provided with an ultrasonic probe. As shown in fig. 2, when the number of the ultrasonic wave sets is two, two sets of ultrasonic wave transmission paths are perpendicular to each other, and the cross section to be measured is divided into (m +1) (n +1) squares, where m is the number of paths included in one set of ultrasonic waves, n is the number of paths included in the other set of ultrasonic waves, both are positive integers, and each transmission path in the same set is uniformly distributed at intervals. The more transmission paths are selected, the more accurate the data obtained and the defect map.
And S3, acquiring the ultrasonic transmission speed on each path by the nonmetal ultrasonic flaw detector. Specifically, as shown in fig. 3, the transmitting end and the receiving end of the ultrasonic probe are placed at both ends of the transmission path, and the ultrasonic flaw detector tests the speed of the ultrasonic wave on the specified transmission path. Fig. 5 is a diagram showing ultrasonic transmission path distribution of a tested section, which is a transverse path and a longitudinal path when two groups of ultrasonic transmission paths are provided, and the path speed of each group is tested by using a nonmetal ultrasonic flaw detector, and then the data is sent to a computer for further processing through the data storage and sending functions of the nonmetal ultrasonic flaw detector.
Because the nonmetal ultrasonic flaw detector belongs to nondestructive testing, the transmitting end and the receiving end of the ultrasonic probe cannot damage the surface of the tree, the end faces of the transmitting end and the receiving end can only be attached to the surface of the tree, a certain included angle can be formed between the end faces of the transmitting end and the receiving end, and the step S4 needs to be carried out for correction according to the transmission characteristic of ultrasonic waves.
As shown in fig. 4, in step S4, the computer performs a correction process on the ultrasonic transmission speed on each path, where the correction formula is:
V＝VN/(-0.2θ2+1)；
where V is the corrected ultrasonic transmission speed, VNIs the ultrasonic transmission speed on the Nth path measured by the ultrasonic flaw detector, N is a positive integer not greater than the total number of the paths, theta is the clamp between the ultrasonic transmission path direction and the ultrasonic emission direction of the ultrasonic probeAnd (4) an angle.
When two sets of ultrasonic transmission paths, a transverse path and a longitudinal path, are provided, the angle θ can be calculated as follows: if each set (transverse path or longitudinal path) of test distributions is symmetrical and uniform, and includes p transport paths, the angle θ of the k-th speed transport path counted from the edge is as follows:
s5, the ultrasonic transmission speed corrected for each path is processed as follows: defining the transmission path as an abnormal path when the following formula is satisfied:
S6, drawing a transmission speed grid map of the whole tree section according to the ultrasonic transmission speed on each path, marking the abnormal path and the normal path with different marks in the grid map, determining the defect position in the grid map through computer data processing and the grid map of the transmission speed, and making a defect schematic diagram.
Taking the number of ultrasonic wave sets as two sets as an example, step S6 includes the following steps:
s61, marking the abnormal path and the normal path determined in step S5 with different marks, where the marks may be in colors, lines, etc., for example, the abnormal path is marked with red, and the normal path is marked with green.
S62, in the transmission speed grid diagram, each grid is composed of four line segments:
when all the line segments in the grid are the marks of the normal path, i.e. all the line segments are green, the grid area is considered to be in a non-defective position.
When one or two parallel line segments in the grid are the marks of the abnormal path, namely red, the defect position is on the straight line where the corresponding line segment is located, but the grid is not located at the defect position.
When two mutually perpendicular line segments or three line segments in the grid are marks of abnormal paths, namely red, the grid part is positioned at a defect.
When four line segments in the grid are the marks of the abnormal paths, namely the abnormal paths are red, the grid is completely positioned at the defect.
When there are only two or three line segments at the edge, the same method can be used to determine, and when there are only two line segments at the edge, the two line segments are necessarily perpendicular, which can be determined according to the third line segment of S62, and when there are only three line segments, it can also be determined according to the third line segment of S62.
Filling and rounding the obtained defective grid, and marking according to the severity of the defect to obtain a cross-section defect schematic diagram; wherein the severity of the defect level is determined by the ratio of the transmission speed to the average speed
It is determined that,
severity of the defect and
in a proportional relationship, i.e.
The larger the defect level.
In order to carry out omnibearing defect detection on trees, Q sections are selected from the trees to be detected along the radial direction or the axial direction of the trees, Q is a positive integer, defect detection is carried out on each section, and when Q is larger, the detection is thinner and more comprehensive.
The invention also provides a tree nondestructive testing device based on the tree defect nondestructive testing method, which comprises an ultrasonic probe, a nonmetal ultrasonic flaw detector connected with the ultrasonic probe and a computer connected with the nonmetal ultrasonic flaw detector; the number of the ultrasonic probes is consistent with the total number of the transmission paths, the ultrasonic probes are set according to the tree defect nondestructive testing method, and the computer is used for detecting tree defects according to the tree defect nondestructive testing method.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (6)
1. A nondestructive detection method for tree defects is characterized by comprising the following steps:
s1, selecting a tree to be detected, and selecting a cross section of the tree to be tested;
s2, selecting two groups of ultrasonic transmission paths with mutually vertical ultrasonic transmission directions on the cross section, wherein each group of paths consists of a plurality of paths, all the ultrasonic transmission paths in each group are distributed in parallel at equal intervals, and each path is provided with an ultrasonic probe;
s3, acquiring the ultrasonic transmission speed on each path by the nonmetal ultrasonic flaw detector;
s4, correcting the ultrasonic transmission speed on each path, the correction formula is:
V＝VN/(-0.2θ2+1)；
wherein V is the corrected ultrasonic transmission speed, VNIs the ultrasonic transmission speed on the Nth path measured by the ultrasonic flaw detector, N is a positive integer not more than the total number of the paths, theta is the included angle between the direction of the ultrasonic transmission path and the ultrasonic emission direction of the ultrasonic probe,
p is the total transmission path number of the ultrasonic wave group where the current transmission path is located, and k refers to the k-th transmission path counted from the edge;
and S5, processing the ultrasonic transmission speed after each path is corrected, and defining the transmission path as an abnormal path when the following formula is satisfied:
s6, drawing a transmission speed grid chart of the whole tree section according to the ultrasonic transmission speed on each path, marking the abnormal path and the normal path with different marks in the grid chart, determining the defect position through the grid chart of the computer data processing and the transmission speed, and making a defect schematic diagram.
2. The tree defect nondestructive testing method of claim 1, wherein step S3 specifically comprises:
the transmitting end and the receiving end of the ultrasonic probe are arranged at two ends of a transmission path, and the nonmetal ultrasonic flaw detector is used for testing the speed of ultrasonic waves on the appointed transmission path.
3. The method for nondestructive detection of tree defects as claimed in claim 2, wherein said step S6 includes the following steps:
s61, marking the abnormal path and the normal path determined in the step S5 by different marks;
s62, in the transmission speed grid diagram, each grid is composed of four line segments:
when all the line segments in the grid are marks of the normal path, the grid area is considered to be in a non-defective position;
when one or two parallel line segments in the grid are the marks of the abnormal path, the defect position is on the straight line where the corresponding line segment is located, but the grid is not located at the defect position;
when two mutually perpendicular line segments or three line segments in the grid are marks of abnormal paths, the grid part is positioned at a defect;
when four line segments in the grid are the labels of the abnormal path, the grid is completely at the defect.
4. The nondestructive testing method for tree defects according to claim 3, wherein the defective grid obtained in step S62 is filled and processed with smoothness, and marked according to the severity of the defects to obtain a cross-sectional defect schematic diagram;
wherein the severity of the defect level is determined by the ratio of the transmission speed to the average speed
It is determined that,
severity of the defect and
in direct proportion.
5. The method of claim 3, wherein the marking symbol is a color.
6. The method of claim 1, wherein the tree to be tested is divided into Q sections along the radial direction, and each section is tested for defects.
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| CN106645178B (en) * | 2017-01-11 | 2023-05-12 | 广西师范大学 | Bamboo splint edge defect detection device |
| CN115047075A (en) * | 2022-06-14 | 2022-09-13 | 苏州大学 | Tree detection method and device and tree detection equipment |
| CN115452948A (en) * | 2022-10-12 | 2022-12-09 | 福州大学 | Intelligent detection method and system for internal defects of rectangular-section wood component |
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| CN107402257A (en) * | 2017-08-14 | 2017-11-28 | 浙江农林大学 | Timber radial longitudinal section defect imaging method based on path packet interpolation method |
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| US7266461B2 (en) * | 2005-12-19 | 2007-09-04 | Weyerhaeuser Co. | Methods for adjusting stress wave velocity-based predictions of lumber stiffness and warp propensity of a timber-based raw material group |
| CN105467012B (en) * | 2015-11-23 | 2018-06-26 | 江南大学 | A kind of method for detecting defective locations on trees radial longitudinal section |
| CN107300587B (en) * | 2017-01-20 | 2020-08-07 | 浙江农林大学 | Tree defect detection method |
| CN106885846B (en) * | 2017-01-20 | 2019-04-23 | 浙江农林大学 | Trees defect detecting device and detection method |
| CN109900789B (en) * | 2019-03-22 | 2020-05-08 | 江南大学 | Imaging method for internal defects of longitudinal section of tree |
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