CN115256563B - High-strength fir glued wood beam, preparation method and bending rigidity index determination method - Google Patents
High-strength fir glued wood beam, preparation method and bending rigidity index determination method Download PDFInfo
- Publication number
- CN115256563B CN115256563B CN202210895626.8A CN202210895626A CN115256563B CN 115256563 B CN115256563 B CN 115256563B CN 202210895626 A CN202210895626 A CN 202210895626A CN 115256563 B CN115256563 B CN 115256563B
- Authority
- CN
- China
- Prior art keywords
- fir
- target
- plywood
- units
- wood beam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27D—WORKING VENEER OR PLYWOOD
- B27D1/00—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring
- B27D1/04—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring to produce plywood or articles made therefrom; Plywood sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27D—WORKING VENEER OR PLYWOOD
- B27D1/00—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring
- B27D1/04—Joining wood veneer with any material; Forming articles thereby; Preparatory processing of surfaces to be joined, e.g. scoring to produce plywood or articles made therefrom; Plywood sheets
- B27D1/08—Manufacture of shaped articles; Presses specially designed therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/46—Wood
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/30—Computing systems specially adapted for manufacturing
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Forests & Forestry (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Rod-Shaped Construction Members (AREA)
Abstract
The invention relates to the technical field of green building materials, in particular to a high-strength fir glued wood beam, a preparation method and a bending rigidity index determination method. The preparation of the high-strength fir glued wood beam comprises the steps of acquiring basic data of a fir plywood unit, dividing quality grades, laterally splicing, finger-jointing, laminating, gluing and the like, can solve the problems of low strength, poor stability, high material cost and the like of the fir glued wood beam in the traditional manufacturing method, and can accelerate the popularization and application of artificial forest fir as a green building material in a building structure. The determination of the bending rigidity index of the high-strength fir glued wood beam comprises the steps of determining the mechanical properties of the fir plywood unit, the fir target plywood, the whole fir glued wood beam and the like, and the bending rigidity index of the fir glued wood beam can be rapidly and accurately determined through the fir plywood unit.
Description
Technical Field
The invention relates to the technical field of green building materials, in particular to a fir glued wood beam, a preparation method thereof and a method for determining bending rigidity indexes.
Background
According to the ninth national forest resource clearing result, the total area of the artificial fir forest is 7950 ten thousand hectares, and the accumulated quantity is 82064 ten thousand meters 3 They are all at the first place of artificial forest. China fir has been the main structural material of ancient architecture in China since ancient times, but the traditional material is solid wood made of large-diameter natural forest, and the material size redundancy is high. The fir wood artificial forest has smaller diameter grade and large mechanical discreteness. Therefore, the high-strength fir glued wood beam needs to be manufactured by a modern scientific and technical method so as to meet the requirements of reasonable materials and safe design of modern wood structures.
At present, due to the lack of a modern scientific manufacturing method, when the laminated wood beam is manufactured by the artificial fir according to a traditional method, the laminated board unit is not subjected to the process flows of material grade grading, assembly optimization and the like, so that when the mechanical property index of the laminated wood beam is valued according to the regulation of GB 50005-2017 wood structure design Standard, the strength grade is the lowest grade TC 11, and the design indexes of bending strength and elastic modulus can only be 11MPa and 9GPa respectively, and the problems that the material cost of the laminated wood beam manufactured by the artificial fir is high and the competitiveness is low compared with that of the laminated wood beam manufactured by other tree species are determined. At present, the abundant artificial forest fir resources in China are basically and completely used in non-structural application fields with lower added values, such as doors, windows, floors, furniture and the like.
Through relevant documents and data retrieval, the standards such as Chinese standards GB 50005, GB/T26899, GB/T50708 and the like only stipulate the requirements of a universal design method of laminated wood, and do not relate to specific fir laminated wood beam products; the disclosed patents include "a manufacturing technology of high-strength laminated wood" (application number: 202111473721.0), "a method for manufacturing laminated wood from small-diameter logs" (application number: 201010534522.1), "a structural laminated wood and a manufacturing method thereof" (application number: 200910085638.9), "a process for manufacturing structural integrated wood from fast-growing poplar" (application number: 201310182966.7), "an integrated wood beam and a manufacturing method thereof" (application number: 10066042.4), "a pressurized preparation process of a laminated wood member based on wood air-dry density parameters" (application number: 2013107272724445.x), and "preliminary research on fir laminated wood of 18 th volume of 2012 th volume of 1998" fir laminated wood ", a preliminary research on 97 th to 99 th volume of 2 th volume of 2012 of 1998," a classification and research on artificial fir performance of 2 th volume of 2012 th volume of 2017 th volume of 2012 th volume of 2017 th volume of, "a mechanical strength of laminated wood in a low-specification of laminated wood, and how to solve the problems of mechanical strength of laminated wood boards of a low-rated laminated wood in a low-visual observation of laminated wood board, and a visual observation research on a mechanical strength of laminated wood board of a laminated wood in the manual research of a low-7 th volume of a high-7 th volume of a laminated wood in the market, and a low-3-7 th volume of a low-year, which are included in the research of a manual research of a mechanical strength of a manual research of a laminated wood board.
From the disclosures of the above documents, the current methods for preparing the high-strength fir laminated wood beam and determining the flexural rigidity index thereof are not provided with corresponding technologies, and cannot meet the requirements of manufacturing and safe use in the field.
Therefore, the method for preparing the high-strength fir laminated wood beam and the method for determining the integral bending rigidity index of the high-strength fir laminated wood beam are provided, so that the high-strength fir laminated wood beam product prepared from the artificial forest fir is realized, the bending rigidity index of the high-strength fir laminated wood beam is accurately evaluated, the product quality of the high-strength fir laminated wood beam is qualified and the product safety application is guaranteed, and the method has very important significance for promoting the high added value application of most of the artificial forest fir in the wood structure and promoting the establishment of a wood structure system with independent intellectual property rights in China.
Disclosure of Invention
The invention aims to provide a high-strength fir glued wood beam, a preparation method and a bending rigidity index determining method, and solves the problems of low strength, poor stability, high material cost and the like of the fir glued wood beam in the traditional manufacturing method through accurate division and optimized assembly of material grades of fir plywood units, and provides an evaluation method suitable for the bending rigidity index of the high-strength fir glued wood beam, and promotes the application of artificial forest fir as a green building material in building structures. .
In order to solve the technical problem, the application provides the following technical scheme:
a preparation method of a high-strength fir glued wood beam comprises the following steps:
(1) Acquiring basic data of a fir plywood unit;
(2) Based on the basic data of the fir veneer units, performing quality grade division on the fir veneer units;
(3) Splicing the fir laminate units along the width direction and performing finger joint along the length direction to form a fir target laminate;
(4) And laminating and gluing the fir target laminate along the thickness direction to synthesize a glued beam with a corresponding target size.
Wherein the step (1) comprises the steps of:
(1-1) sawing, drying and finely planing the Chinese fir logs to manufacture Chinese fir laminate units with the length of 2000-4000 mm, the width of 50-200 mm and the thickness of 15-50 mm, wherein the dried target average water content of the Chinese fir laminate units is 12%;
(1-2) testing the China fir plywood units by adopting a nondestructive dynamic tester to obtain the dynamic elastic modulus of each China fir plywood unit, and recording the dynamic elastic modulus as E D,i (ii) a Measuring the dynamic density of each fir plywood unit and recording as rho D,i 。
Wherein the step (2) comprises the steps of:
(2-1) dividing the Chinese fir plywood units into 5 material grades which are respectively marked as MS H 、MS I 、MS II 、MS III 、MS R The dynamic elastic modulus and dynamic density limit ranges corresponding to different material grades are as follows:
material quality grade MS H ：E D,i Not less than 11.2GPa and rho D,i ≥0.48g/cm 3 ；
Material quality grade MS I ：9.4GPa≤E D,i And 0.43g/cm 3 ≤ρ D,i ；
Material quality grade MS II ：7.6GPa≤E D,i And 0.38g/cm 3 ≤ρ D,i ；
Material quality grade MS III ：5.8GPa≤E D,i And 0.33g/cm 3 ≤ρ D,i ；
Material quality grade MS R ：E D,i < 5.8GPa or rho D,i ＜0.33g/cm 3 ；
(2-2) obtaining the dynamic elastic modulus E of the fir plywood unit prepared in the step (1) through testing by a nondestructive dynamic tester D,i And dynamic density ρ D,i According to the material grade division method in the step (2-1), MS belonging to the material grade is judged I 、MS II Or MS III Chinese fir (Japanese cedar)The ratio of the number of the wood laminate units to the number of the whole fir laminate units is not less than 90%; MS for judging material quality H Or MS R The ratio of the number of the fir plywood units to the number of the whole fir plywood units is not more than 10%.
And (3) recording the width b, the height h and the length L of the finally prefabricated target glued wood beam, splicing the fir laminate units made of the same grade material laterally to enable the width of the fir laminate units to be equal to the width b of the target glued wood beam, and then extending the fir laminate units by finger joint to enable the length of the fir laminate units to be equal to the length L of the target glued wood beam to obtain the fir target laminate.
Wherein the step (4) comprises the steps of:
(4-1) gluing the target Chinese fir plywood on a single surface, wherein the gluing amount is 280-330 g/m 2 ；
(4-2) assembling the glued fir target laminate by adopting fir target laminates with different material grades along the height h direction of the target glued wood beam;
arranging the materials with the grade of MS within the range of the height h/7 of the upper side and the lower side of the glued wood beam I The arrangement layer number of the fir target laminate is i layers; in close proximity to MS I The height h/7 range of the China fir target laminate arrangement interval to the center direction of the target glued wood beam is MS II Arranging j layers of fir target laminates; arranging the material grade to be MS within the range of 3h/7 of the height of the middle of the target laminated wood beam III Arranging k layers of fir target laminates;
(4-3) laminating and gluing the assembled target Chinese fir plywood to obtain a target glued wood beam, wherein the pressure is 0.5-0.8 MPa, the cold pressing time is more than 8 hours, and the pressure compensation is performed once after the initial cold pressing time is 15 min;
(4-4) placing the laminated and glued target glued wood beam in an environment with the temperature of 20-40 ℃ and the humidity of 40% -70% for curing for at least 1 week.
The average value of the bending elastic modulus of the high-strength fir laminated wood beam prepared by the preparation method is not less than 13GPa, the variation coefficient is less than 10 percent, the average value of the bending strength is not less than 34MPa, and the variation coefficient is less than 15 percent.
A method for determining flexural rigidity indexes of a high-strength fir laminated wood beam comprises the following steps:
(1) Obtaining the static elastic modulus of the fir veneer units;
(2) Determining static elastic modulus indexes of target laminates of the fir with different material grades;
(3) And determining the bending rigidity index of the fir laminated wood beam.
Wherein the step (1) comprises the steps of:
(1-1) selecting fir plywood units with different material grades, which are prepared by the preparation method of the high-strength fir glued wood beam according to the claims 1-5, and selecting the material grade as MS I 、MS II 、MS III The number of the fir plywood units selected by each material grade is not less than 53;
and (1-2) carrying out static bending resistance mechanical property test on the selected fir laminate units, and measuring the static elastic modulus of each fir laminate unit in each material grade.
Wherein the step (2) comprises the steps of:
(2-1) aiming at the static elastic modulus of each fir laminate unit in each material grade obtained in the step (1), taking the average value of the confidence degrees of 75% of the static elastic modulus of all fir laminate units in each material grade as the static elastic modulus index of the fir laminate unit in the material grade, and taking the material grade MS I 、MS II 、MS III The static elastic modulus index of the fir plywood unit is respectively marked as E S,I 、E S,II 、E S,III ；
(2-2) the fir target laminate prepared in the method for preparing the high-strength fir glued wood beam according to the claims 1 to 5 is the same as the fir laminate unit with the same material grade in static elastic modulus index.
Wherein the step (3) comprises the steps of:
(3-1) pairsThe fir glued wood beam prepared by the method for preparing the high-strength fir glued wood beam as claimed in claim 1 to 5, wherein the neutral axis position of the fir glued wood beam is positioned at the height center of the cross section of the beam, and the vertical height from the center of each layer of fir target laminate to the neutral axis is recorded as y n And the cross section inertia moment of each layer of the target Chinese fir plywood is recorded as I n The cross-sectional area is denoted A n ；
(3-2) calculating the bending rigidity index, marked as EI, of the fir laminated wood beam according to the following formula:
compared with the prior art, the high-strength fir laminated wood beam, the preparation method and the bending rigidity index determining method have the following beneficial effects:
according to the manufacturing method, the material grades of the fir plywood units are accurately divided, the assembly is optimized, the average value of the bending elasticity modulus of the manufactured fir glued wood beam is not less than 13GPa, the variation coefficient is less than 10%, the average value of the bending strength is not less than 34MPa, the variation coefficient is less than 15%, and the percentage of the assembled fir plywood units used for manufacturing the fir glued wood beam is more than 90%. The method can solve the problems of low strength, poor stability, high material cost and the like of the fir laminated wood beam in the traditional manufacturing method, can accurately predict the bending rigidity of the fir laminated wood beam, and accelerates the popularization and application of artificial forest fir as a green building material in a building structure.
The high-strength fir laminated wood beam, the preparation method thereof and the method for determining the flexural rigidity index of the high-strength fir laminated wood beam are further described below with reference to the accompanying drawings.
Drawings
FIG. 1 shows the corresponding limit ranges of the fir plywood units with different material grades in the preparation process of the high-strength fir laminated wood beam.
FIG. 2 is a schematic diagram of the distribution of the fir plywood units of different material grades in the preparation process of the high-strength fir laminated wood beam. Wherein r is a material grade MS I 、MS II 、MS III The proportion of the fir plywood units.
FIG. 3 is a schematic structural diagram of a target laminate of fir wood during the preparation of the high strength fir laminated wood beam of the present invention.
FIG. 4 is a schematic assembly view of a fir target plywood in the process of manufacturing the high-strength fir laminated wood beam of the invention.
FIG. 5 is a schematic diagram of the flexural rigidity calculation of each layer of fir target laminate in the determination process of the flexural rigidity index of the high-strength fir laminated wood beam.
Detailed Description
Example 1
Referring to fig. 1 to 4, a method for manufacturing a high-strength fir laminated wood beam includes the following steps:
(1) Obtaining basic data of fir plywood unit
(1) The cedar logs are manufactured into cedar laminate units with the length of 4000mm, the width of 140mm and the thickness of 35mm through sawing, drying, fine planing and other process flows, and the target average water content of the dried cedar laminate units is 12%;
(2) testing the above fir plywood units by using a nondestructive dynamic tester to obtain the dynamic elastic modulus of each fir plywood unit, and recording as E D,i Measuring the dynamic density of each fir plywood unit and recording as rho D,i 。
(2) Based on the basic data of the fir plywood units, performing quality grade division on the fir plywood units, as shown in figure 1;
(1) dividing the fir plywood units into 5 material grades, and respectively recording the grades as MS H 、MS I 、MS II 、MS III 、MS R As shown in fig. 1, the dynamic elastic modulus and dynamic density limit ranges corresponding to different material grades are as follows:
material quality grade MS H ：E D,i Not less than 11.2GPa and rho D,i ≥0.48g/cm 3 ；
Material quality grade MS I ：9.4GPa≤E D,i And 0.43g/cm 3 ≤ρ D,i ；
Material quality grade MS II ：7.6GPa≤E D,i And 0.38g/cm 3 ≤ρ D,i ；
Material quality grade MS III ：5.8GPa≤E D,i And 0.33g/cm 3 ≤ρ D,i ；
Material quality grade MS R ：E D,i < 5.8GPa or rho D,i ＜0.33g/cm 3 ；
(2) The fir plywood unit prepared according to the step (1) is tested by a nondestructive dynamic tester to obtain the dynamic elastic modulus E D,i And dynamic density ρ D,i MS in 2300 China fir plywood units according to the material grading method I 、MS II Or MS III The number of the fir plywood units is 2116, and the ratio of the number of the fir plywood units to the number of the whole fir plywood units is 92 percent; MS (Mass Spectrometry) H Or MS R The ratio of the number of fir wood laminate units to the total number of fir wood laminate units is 8%, as shown in table 1 and fig. 2.
TABLE 1 number of fir plywood units
| Numbering | Grade of | Number/root | Ratio (%) |
| 1 | MS H | 46 | 2 |
| 2 | MS I | 460 | 20 |
| 3 | MS II | 782 | 34 |
| 4 | MS III | 874 | 38 |
| 5 | MS R | 138 | 6 |
(3) Splicing the fir plywood units along the width direction and finger-jointing the fir plywood units along the length direction to form a fir target plywood:
the width of the finally prefabricated target glued wood beam is b =140mm, the height is h =245mm, and the length is L =6000mm, the fir-wood laminate units made of the same grade material are firstly spliced through the side, so that the width of the fir-wood laminate units is equal to the width of the target glued wood beam, and then the fir-wood laminate units are lengthened through finger joint, so that the length of the fir-wood laminate units is equal to the length of the target glued wood beam, as shown in figure 3.
(4) Laminating and gluing the fir target laminate along the thickness direction to form a glued beam with a corresponding target size, as shown in figure 4.
(1) The target Chinese fir plywood is coated with glue on one side, and the coating amount is 300g/m 2 ；
(2) Assembling the glued fir target laminate by adopting fir target laminates with different material grades along the height h direction of the target glued wood beam, wherein the number of assembled layers is 7;
in glued wood beamUpper and lower side height h/7 range, i.e., upper and lower 1 st fir target laminate material grade arrangement as MS I In close proximity to MS I The inward height h/7 range of the China fir target laminate arrangement interval is that 1 layer of MS material is arranged II The China fir target laminate is arranged with 3 layers of materials with the grade of MS within the range of 3h/7 of the height of the middle of the glued wood beam III The fir target plies of (1), as shown in fig. 4;
(3) laminating and gluing the assembled target Chinese fir plywood to obtain a target glued wood beam, wherein the pressure is 0.8MPa, the cold pressing time is more than 8 hours, and the pressure compensation is carried out once after the initial cold pressing time is 15 min;
(4) the laminated and glued target glued wood beam should be placed in an environment with the temperature of 32 ℃ and the humidity of 56% for curing for 1 week.
The fir laminated wood beam manufactured by the method is randomly selected from 10 fir laminated wood beams, and the bending strength and the bending elastic modulus are tested according to GB/T50329-2012, wood Structure test method, and the results are shown in Table 2. The results showed that the mean value of the bending strength of the fir laminated wood beam was 36.5MPa and the coefficient of variation was 7.6%, and the mean value of the bending modulus of elasticity was 13.8GPa and the coefficient of variation was 4.9%.
TABLE 2 bending resistance test results of fir laminated wood beam
Example 2
The method for determining the flexural rigidity index of the high-strength fir laminated wood beam manufactured in example 1, as shown in fig. 5, includes the following steps:
(1) Obtaining static elastic modulus of fir plywood unit
(1) For the fir plywood units with different material grades prepared in the example 1, the material grade is selectedIs MS I 、MS II 、MS III The number of the fir veneer units selected by each material grade is 60;
(2) and (3) carrying out a static bending resistance mechanical property test on the selected fir laminate units according to GB/T26899-2011 structural laminated wood, and measuring the static elastic modulus of each fir laminate unit in each material grade.
(2) Determining static elastic modulus indexes of target laminates of fir with different material grades
(1) For the static elastic modulus of each fir laminate unit in each material grade obtained above, taking the average value of the confidence degrees of 75% of the static elastic modulus of all fir laminate units in each material grade as the static elastic modulus index of the fir laminate unit in the material grade, and the material grade MS I 、MS II 、MS III The static elastic modulus indexes of the fir plywood units are respectively E S,I ＝14.5GPa、E S,II ＝13.3GPa、E S,III ＝12.1GPa；
(2) The static elastic modulus index of the fir target laminate prepared in the embodiment 1 is the same as that of the fir laminate unit with the same material grade.
(3) Determining bending rigidity index of fir laminated wood beam
(1) For the fir glued wood beam prepared in the example 1, the neutral axis position of the fir glued wood beam is positioned at the height center of the beam section, and the vertical height from the center of each layer of fir target laminate to the neutral axis is recorded as y n And the cross section inertia moment of each layer of the target Chinese fir plywood is recorded as I n And the cross-sectional area is marked A n As shown in fig. 5 and table 3, the bending stiffness index of the fir laminated wood beam, denoted as EI, can be calculated as follows:
TABLE 3 calculation of fir laminated wood beam flexural rigidity index
The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (3)
1. A preparation method of a high-strength fir glued wood beam is characterized by comprising the following steps: the method comprises the following steps:
(1) Acquiring basic data of a fir plywood unit; the method specifically comprises the following steps:
(1-1) sawing, drying and finely planing a fir log to manufacture a fir laminate unit with the length of 2000-4000 mm, the width of 50mm-200mm and the thickness of 15mm-50mm, wherein the target average water content of the dried fir laminate unit is 12%;
(1-2) testing the China fir plywood units by adopting a nondestructive dynamic tester to obtain the dynamic elastic modulus of each China fir plywood unit, and recording the dynamic elastic modulus as
(ii) a The dynamic density of each fir plywood unit is measured and recorded as
；
(2) Based on the basic data of the fir plywood units, performing quality grade division on the fir plywood units; the method specifically comprises the following steps:
(2-1) dividing the Chinese fir plywood units into 5 material grades which are respectively marked asMS H 、MS I 、MS II 、MS III 、MS R The dynamic elastic modulus and dynamic density limit ranges corresponding to different material grades are as follows:
material gradeMS H ：
And is
；
Material gradeMS I ：
And is
；
Grade of materialMS II ：
And is
；
Material gradeMS III ：
And is
；
Material gradeMS R ：
Or
；
(2-2) obtaining the dynamic elastic modulus of the fir plywood unit prepared in the step (1) through testing by a nondestructive dynamic tester
And dynamic density
According to the step (2-1)Quality grade classification method for judging material quality gradeMS I 、MS II OrMS III The ratio of the number of the fir plywood units to the number of the whole fir plywood units is not less than 90 percent; discriminating the material belonging to the material classMS H OrMS R The ratio of the number of the Chinese fir plywood units to the number of the whole Chinese fir plywood units is not more than 10 percent;
(3) Splicing the fir plywood units along the width direction and finger-jointing the fir plywood units along the length direction to form a fir target plywood; recording the width b, the height h and the length L of a target glued wood beam to be finally prefabricated, firstly splicing the fir plywood units made of the same grade material laterally to enable the width of the fir plywood units to be equal to the width b of the target glued wood beam, and then extending the fir plywood units in a finger joint mode to enable the length of the fir plywood units to be equal to the length L of the target glued wood beam to obtain a fir target plywood;
(4) Laminating and gluing the target Chinese fir plywood along the thickness direction to form a gluing beam with a corresponding target size,
(4-1) gluing the target Chinese fir laminate on one side, wherein the gluing amount is 280-330g/m 2 ；
(4-2) assembling the glued fir target laminate by adopting fir target laminates with different material grades along the height h direction of the target glued wood beam;
the upper side and the lower side of the glued wood beam have the height h/7 range, and the arrangement material grade isMS I The arrangement layer number of the fir target laminate is i layers; in the immediate vicinity ofMS I The height h/7 range of the China fir target laminate arrangement interval to the center direction of the target glued wood beam is that the arrangement material grade isMS II Arranging j layers of fir target laminates; in the range of 3h/7 of the height of the middle of the target laminated wood beam, the arrangement material grade isMS III Arranging k layers of fir target laminates;
(4-3) laminating and gluing the assembled fir target laminate to obtain a target glued wood beam, wherein the pressure is 0.5 to 0.8MPa, the cold pressing time is more than 8 hours, and the pressure compensation is performed once after the initial cold pressing time is 15 min;
(4-4) placing the laminated and glued target glued wood beam in an environment with the temperature of 20 to 40 ℃ and the humidity of 40 to 70 percent for curing for at least 1 week.
2. The high-strength fir laminated wood beam manufactured by the method for manufacturing a high-strength fir laminated wood beam as claimed in claim 1, wherein: the average value of the bending elastic modulus is not less than 13GPa, the variation coefficient is less than 10 percent, the average value of the bending strength is not less than 34MPa, and the variation coefficient is less than 15 percent.
3. A method for determining flexural rigidity indexes of a high-strength fir laminated wood beam is characterized by comprising the following steps:
(1) Acquiring the static elastic modulus of the fir plywood unit; specifically, the method comprises the following steps of,
(1-1) selecting the fir plywood units with different material grades, which are prepared by the preparation method of the high-strength fir glued wood beam in the claim 1, as the material gradesMS I 、MS II 、MS III The number of the fir plywood units selected by each material grade is not less than 53;
(1-2) carrying out static bending resistance mechanical property test on the selected fir laminate units, and measuring the static elastic modulus of each fir laminate unit in each material grade;
(2) Determining static elastic modulus indexes of target laminates of the fir with different material grades; specifically, the method comprises the following steps of,
(2-1) aiming at the static elastic modulus of each fir laminate unit in each material grade obtained in the step (1), taking the average value of the confidence degrees of 75% of the static elastic modulus of all fir laminate units in each material grade as the static elastic modulus index of the fir laminate unit in the material grade, and obtaining the static elastic modulus index of the fir laminate unit in each material gradeMS I 、MS II 、MS III The static elastic modulus indexes of the fir plywood units are respectively recorded as
、
、
；
(2-2) the fir target laminate prepared in the preparation method of the high-strength fir glued wood beam according to claim 1 is the same as the fir laminate unit with the same material grade in static elastic modulus index value;
(3) Determining the bending rigidity index of the fir glued wood beam; specifically, the method comprises the following steps of,
(3-1) the fir plywood beam obtained by the method for preparing the high-strength fir plywood beam according to claim 1, wherein the neutral axis position of the fir plywood beam is positioned at the height center of the cross section of the beam, and the vertical height from the center of each layer of fir target laminate to the neutral axis is recorded as
The cross-sectional moment of inertia of each target layer of fir is recorded as
And cross-sectional area is noted
；
(3-2) for the fir glued wood beam, the bending rigidity index is recorded
Calculated according to the following formula:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210895626.8A CN115256563B (en) | 2022-07-27 | 2022-07-27 | High-strength fir glued wood beam, preparation method and bending rigidity index determination method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210895626.8A CN115256563B (en) | 2022-07-27 | 2022-07-27 | High-strength fir glued wood beam, preparation method and bending rigidity index determination method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115256563A CN115256563A (en) | 2022-11-01 |
| CN115256563B true CN115256563B (en) | 2023-03-21 |
Family
ID=83771276
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210895626.8A Active CN115256563B (en) | 2022-07-27 | 2022-07-27 | High-strength fir glued wood beam, preparation method and bending rigidity index determination method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115256563B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116029106B (en) * | 2022-12-22 | 2023-08-18 | 中国林业科学研究院木材工业研究所 | Quality control system and method for laminated wood plate unit |
| CN115931596B (en) * | 2022-12-22 | 2023-08-04 | 中国林业科学研究院木材工业研究所 | Quality control system and method for sawn timber for structure |
| CN116330410A (en) * | 2023-03-30 | 2023-06-27 | 中国林业科学研究院木材工业研究所 | Paulownia wood for nuclear waste transportation buffer and preparation and compression resistance index determination method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001289760A (en) * | 2000-04-06 | 2001-10-19 | Ibiden Co Ltd | Device and method for determining lumber grade |
| CN103072159B (en) * | 2013-01-28 | 2014-12-24 | 南京工业大学 | Prestressed laminated wood with creep deformation resistance and preparation method and application thereof |
| CN104777289A (en) * | 2015-04-08 | 2015-07-15 | 北京林业大学 | Method for efficiently and accurately determining flexural rigidity of structural laminated wood beam |
| CN106272764B (en) * | 2016-08-25 | 2018-05-25 | 国际竹藤中心 | The stage division of specification bamboo cane modulus and density |
-
2022
- 2022-07-27 CN CN202210895626.8A patent/CN115256563B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN115256563A (en) | 2022-11-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115256563B (en) | High-strength fir glued wood beam, preparation method and bending rigidity index determination method | |
| Porteous et al. | Structural timber design to Eurocode 5 | |
| Kalaycioglu et al. | Some of the properties of particleboard made from paulownia | |
| Komariah et al. | Physical-mechanical properties of glued laminated timber made from tropical small-diameter logs grown in Indonesia | |
| Kılıç | The effects of the force loading direction on bending strength and modulus of elasticity in laminated veneer lumber (LVL) | |
| Gong et al. | Block shear strength and delamination of cross-laminated timber fabricated with Japanese larch | |
| Rahman et al. | Some physical and mechanical properties of bamboo mat-wood veneer plywood | |
| Wang et al. | Evaluation of mechanical properties of reinforced poplar laminated veneer lumber | |
| Wang et al. | Effect of macro characteristics on rolling shear properties of fast-growing poplar wood laminations | |
| Srivaro et al. | Properties of mixed species/density cross laminated timber made of rubberwood and coconut wood | |
| Srivaro et al. | Performance of cross laminated timber made of oil palm trunk waste for building construction: a pilot study | |
| Ogunsanwo et al. | Effect of adhesive quantity on selected physico-mechanical properties of Bamboo glulam | |
| Baskara et al. | Physical and mechanical properties of oriented strand board from three species of plantation forests at various resin contents | |
| Wronka et al. | Selected properties of particleboard made of raspberry Rubus idaeus L. lignocellulosic particles | |
| Chui et al. | Effects of resin impregnation and process parameters on some properties of poplar LVL | |
| Kurt et al. | Manufacturing of parallel strand lumber (PSL) from rotary peeled hybrid poplar I-214 veneers with phenol formaldehyde and urea formaldehyde adhesives | |
| Park et al. | Static bending strength performances of cross-laminated wood panels made with six species | |
| Moya et al. | Ultrasound velocity mapping to evaluate gluing quality in CLT panels from plantation wood species | |
| Hrázský et al. | A contribution to the properties of combined plywood materials | |
| Serrano et al. | Green-glued laminated beams: High performance and added value | |
| Kūliņš et al. | Influence of veneer density on plywood thickness and some mechanical properties | |
| Newton et al. | Utilization of ground peanut husk as an alternative fiber material for particleboard | |
| Yang et al. | Effect of laminate configuration on the modulus of elasticity of glulam evaluated using a strain gauge method | |
| Barboutis et al. | Properties of two different thicknesses 3-ply plywood of tree-of-heaven veneers. | |
| Chai et al. | Production of oil palm trunk core board with wood veneer lamination |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |