GB/T 1927-2009Test methods for physical and mechanical properties of small clear wood specimens - Part 1: Collection of sample tree (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted:

This document is part 1 of GB/T 1927 "Test Methods for Physical and Mechanical Properties of Small Specimens of Wood without Defects": GB/T 1927 has been released the following parts:

--- Part 1: Collection of test materials;

--- Part 2: Sampling methods and general requirements;

--- Part 3: Determination of growth ring width and latewood rate;

--- Part 4: Determination of moisture content;

--- Part 5: Density determination;

--- Part 6: Determination of dry shrinkage;

--- Part 7: Determination of water absorption;

--- Part 8: Determination of swelling properties;

--- Part 9: Determination of flexural strength;

--- Part 10: Determination of flexural modulus of elasticity;

--- Part 12: Determination of transverse grain compressive strength;

--- Part 17: Determination of impact toughness;

--- Part 18: Determination of impact indentation;

--- Part 19: Determination of hardness;

--- Part 20: Determination of splitting resistance:

This document replaces GB/T 1927-2009 "Wood Physical Mechanics Test Material Collection Method", compared with GB/T 1927-2009, except for the structure in addition to adjustments and editorial changes, the main technical changes are as follows:

a) Changed the requirements for defects in the selection of samples (see 4.3:2, 3:3:2 of the:2009 edition);

b) Added log length requirements (see 5.3);

c) Added requirements for log defects (see 5.4);

d) Changed the requirements for sawing logs into center board test materials (see 5.5, 4:3 of the:2009 edition);

e) Deleted the requirements for the number position after the test material was intercepted (see 5.1 of the:2009 edition);

f) Added the column "shape rate" in Table B:1 of Appendix B (see Table B:1):

This document is modified by ISO 4471:1982 "Sampling of wood samples and logs for the determination of physical and mechanical properties of wood in the same type of stand method":

Compared with ISO 4471:1982, this document has the following structural adjustments:

--- Chapter 4 corresponds to Chapter 4 and Chapter 5 in ISO 4471:1982, of which 4:3:1 and 4:3:2 correspond to ISO 4471:1982 5:1, added 4:3:3 and 4:3:4;

--- Chapter 5 and Chapter 6 correspond to Chapter 6 in ISO 4471:1982, of which 5:3 and 5:4 correspond to ISO 4471:1982 6:1 and 6:2, 5:1, 5:2, 5:5 and 5:6 have been added; 6:1 corresponds to 6:4 in ISO 4471:1982, and 6:2 corresponds to ISO 4471:

6:3 in 1982;

---Appendix B corresponds to Appendix D in ISO 4471:1982:

The technical differences between this document and ISO 4471:1982 and their reasons are as follows:

--- Regarding normative reference documents, this document has made adjustments with technical differences to adapt to the technical conditions of our country and the circumstances of the adjustment:

The situation is reflected in Chapter 2 "Normative References", and the specific adjustments are as follows:

- Replace ISO 3129 with GB/T 1927.2 which is modified to adopt international standard;

- Replace ISO 13061-1 with GB/T 1927.4 which is modified to adopt international standard;

--- Added the citation standards GB/T 26423-2010 and LY/T 1788 (see Chapter 3) for terms and definitions introduction;

--- Changed the choice of collecting stands (see 4.1, 4:1 of ISO 4471:1982), with stronger operability;

--- Added the requirement for sample wood sampling of the same species (see 4.3:3) to ensure the representativeness of sample wood selection;

---Added the sampling requirements for tree species that cannot meet the requirements for setting the collection site (see 4.3:4) to ensure that when some tree species cannot meet the requirements for sampling Sampling can still be carried out in accordance with this document when the site setting requirements are met;

--- Added the measurement requirements before and after felling the sample wood and the precautions when felling (see 5.1):

--- Changed the method of intercepting logs from the sample (see 5.3, 6:1 of ISO 4471:1982), which not only ensures the location of the second segment of logs from the root neck to the middle of the height under the branch, it reflects the wood properties of the sample more scientifically, and it better covers the possibility of forestry production practice:

The different situations that occur are in line with the practice of collecting test materials for the study of wood properties in my country;

--- Added the description of the collection of wax leaf specimens (see 5.2);

--- Increase the provisions for sawing the center plate test material when the transportation conditions are limited (see 5.5);

--- Increased the provisions for determining the moisture content of raw wood (see 5.6);

--- Changed the collection record table (see Appendix A, Appendix A of ISO 4471:1982);

--- Changed the sample log table (see Appendix B, Appendix D of ISO 4471:1982):

The following editorial changes have been made to this document:

--- In order to harmonize with the existing standards, the name of the standard is changed to "Test methods for physical and mechanical properties of wood with small samples without defects - Part 1: Test material collection";

--- Delete Appendix B and Appendix C to be consistent with the content of 4:1;

--- Deleted Appendix E to be consistent with the contents of 5:1 and 6:1:

Please note that some content of this document may be patented: The issuing agency of this document assumes no responsibility for identifying patents:

Introduction

The standard of test methods for physical and mechanical properties of wood is used in wood scientific research, teaching, wood inspection, wood structure design, wood processing and production, etc:

It is widely used and is an important basic standard in the wood industry: In 1980, my country issued the first edition of the test methods for physical and mechanical properties of wood:

The domestic standard (GB/T 1927~GB/T 1943) was revised twice in:1991 and:2009 respectively: In recent years, with the development of wood science and technology the development of technology, ISO 3129:2012 "Sampling methods for wood physical and mechanical tests of small samples of wood without defects and "General Requirements" has been revised, and ISO 3130:1975 "Determination of moisture content by physical and mechanical tests of wood", ISO 3131:1975 "Wood material 15 international standards for test methods such as "Determination of Density in Physical and Mechanical Tests" have been integrated and revised: Based on this, in order to be in line with international standards, this time the third revision of the national standard for test methods for physical and mechanical properties of wood in my country has been carried out, and the 22 scattered test methods have been integrated and adjusted to the sub-part document of GB/T 1927 adopts the latest version of the international standard in the revision:

GB/T 1927 aims to establish a test method for the physical and mechanical properties of small sample wood without flaws, and is intended to be composed of 21 parts:

--- Part 1: Collection of test materials: The purpose is to describe the sample collection method for testing the physical and mechanical properties of wood with small samples without defects:

--- Part 2: Sampling methods and general requirements: The purpose is to establish a suitable test for the physical and mechanical properties of small wood samples without defects:

Specimen sawing, interception methods and general requirements to be observed when testing methods:

--- Part 3: Determination of growth ring width and latewood rate: The purpose is to characterize the growth ring width and latewood rate of small samples of clear wood method of measurement:

--- Part 4: Determination of moisture content: The purpose is to describe a method for the determination of the moisture content of small wood samples without defects:

--- Part 5: Density determination: The purpose is to describe the density, air-dry density, absolute dry Methods for the determination of density and basic density:

--- Part 6: Determination of dry shrinkage: The purpose is to describe the measurement of radial, chordwise and volume drying shrinkage of unblemished small sample wood:

determined method:

--- Part 7: Determination of water absorption: The purpose is to describe the determination method of 6h, 24h and the maximum water absorption rate of small sample wood without defect:

--- Part 8: Determination of swelling: The purpose is to describe the measurement of radial, chordwise and volumetric swell of unblemished small wood samples:

determined method:

--- Part 9: Determination of flexural strength: The purpose is to describe a method for the determination of the flexural strength of small wood samples without defects:

--- Part 10: Determination of flexural modulus of elasticity: The purpose is to describe a method for the determination of the flexural modulus of elasticity of small wood samples without defects:

--- Part 11: Determination of compressive strength along grain: The purpose is to describe a method for the determination of the compressive strength along the grain of small wood samples without defects:

--- Part 12: Determination of transverse grain compressive strength: The purpose is to describe the transverse grain compressive proportional ultimate strength of small unblemished wood samples, including Methods for the determination of the total compressive proportional ultimate strength of the horizontal grain and the partial compressive proportional ultimate strength of the horizontal grain:

--- Part 13: Determination of compressive elastic modulus of transverse grains: The purpose is to describe the measurement of the transverse-grain compressive elastic modulus of unblemished small samples of wood:

determined method:

--- Part 14: Determination of tensile strength along grain: The purpose is to describe a method for the determination of the along-grain tensile strength of unblemished small samples of wood:

--- Part 15: Determination of transverse grain tensile strength: The purpose is to describe a method for the determination of the transverse grain tensile strength of small wood samples without defects:

--- Part 16: Determination of shear strength along grain: The purpose is to describe a method for the determination of the shear strength along the grain of small wood samples without defects:

--- Part 17: Determination of impact toughness: The purpose is to describe a method for the determination of the chordwise impact toughness of small unblemished wood samples:

--- Part 18: Determination of impact indentation: The purpose is to describe a method for the determination of the impact indentation resistance of unblemished small samples of wood:

--- Part 19: Determination of hardness: The purpose is to describe a method for the determination of radial, chord, and longitudinal hardness of small, unblemished wood samples:

--- Part 20: Determination of splitting resistance: The purpose is to describe the method for the determination of the splitting resistance on the radial and chord surfaces of small wood samples without defects:

--- Part 21: Determination of nail holding force: The purpose is to describe a method for the determination of the nail-holding force of small samples of wood without defects:

Test method for physical and mechanical properties of wood with small sample without defect Part 1: Collection of test materials

1 Scope

This document describes the test method for the physical and mechanical properties of wood with small samples without defects:

material interception and recording, as well as test material numbering and transportation:

This document is applicable to the collection of test materials for the study of wood physical and mechanical properties of standing trees of the same type:

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text: Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document:

GB/T 1927.2 Test methods for physical and mechanical properties of wood with small unblemished samples - Part 2: Sampling methods and general requirements (GB/T 1927.2-2021, ISO 3129:2019, MOD) GB/T 1927.4 Test methods for physical and mechanical properties of wood with small flawless specimens - Part 4: Determination of moisture content (GB/T 1927.4-2021, ISO 13061-1:2014, MOD) GB/T 26423-2010 Forest Resource Terminology LY/T 1788 Terms for wood properties

3 Terms and Definitions

The terms and definitions defined in GB/T 26423-2010 and LY/T 1788 and the following terms and definitions apply to this document:

homogeneousstand

A forest area that has the same internal forestry characteristics and is significantly different from the surrounding areas:

canopy density crowndensity; shadedensity the ratio of the vertical projected area of the canopy to the woodland area:

Note: expressed in tenths:

[Source: GB/T 26423-2010, 6:42, with modifications] 3.3 root neck rootcolar the part of a standing tree that is transformed from a root to a stem:

diameter at breast height; DBH the diameter of the trunk above the ground surface at breast height:

Note: Generally, the height of the chest is set as the height of 1:3m above the root neck: