GB/T 1928-2009General requirements for physical and mechanical tests of wood (English PDF)

Foreword

This standard and the international standard ISO 3129. 1975 "sampling methods physical and mechanical tests and general requirements," the degree of consistency Non-equivalent.

This standard replaces GB/T 1928-1991 "General physical and mechanical test methods." this standard compared with GB/T 1928-1991 The main changes are as follows.

--- 3.2 improves the accuracy of the production samples;

--- Chapters 4 and 5 are improved when the sample moisture adjusting the relative humidity control accuracy.

This standard was proposed by the State Forestry Administration.

This standard by the National Standardization Technical Committee timber.

1 Scope

This standard specifies the requirements for sample preparation to adjust the physical and mechanical tests and inspections, the moisture content of the sample, laboratory requirements, test set Calibration equipment, as well as the calculation of the test results and test preparation of the report.

This standard applies to the physical and mechanical properties of wood unblemished small sample test.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 8170 repair value expressed about the rules and limit values \u200b\u200band judgment

3 Sample preparation and testing accuracy

3.1 Each sample should be flat surface, wherein two opposite edges on the end should be roughly parallel to the growth ring of the sample end, and with the other two Vertical edges, does not allow the obvious visible defects on the sample, each sample should be clearly written on the numbers.

3.2 precision sample preparation, in addition to the specific requirements of the test method, the adjacent surface of the specimen shall be as precise right angles. Sample length , Width, and thickness tolerance of ± 0.5mm. In the relative deviation of dimensions on the entire sample, should be less than 0.1mm.

3.3 The accuracy of the sample perpendicular to the adjacent surface, steel rectangular device test.

4 Adjust the sample moisture content

After air-drying or drying chamber (lower than 60 °C temperature conditions) or sample blank sample strips made of treated, it should be placed in the equivalent Wood equilibrated water content was 12% of the environmental conditions, to adjust the moisture content of the sample equilibrium, the equilibrium moisture content of wood in order to meet the environmental conditions of 12% Requirements, when the room temperature (20 ± 2) °C, relative humidity should be maintained at (65 ± 3)%; when the temperature is lower or higher than (20 ± 2) °C, the corresponding need Decrease or increase the relative humidity to ensure that the equilibrium moisture content of wood to reach 12% of the environmental conditions.

5 Laboratory temperature and humidity conditions

The laboratory shall maintain the temperature (20 ± 2) °C and relative humidity (65 ± 3)%. Such as the laboratory can not maintain this condition, the adjusted aqueous Sample rate should be sent to the laboratory after the first into a closed container, when the test taken.

Test equipment calibration 6 Testing machine, and other precision measuring instruments measuring test, regular test verification procedures in accordance with national measurement sector, load testing machine Indication accuracy of ± 1.0%.

7 to prepare calculations and test results of the test report

7.1 The test results of the physical and mechanical properties, shall be calculated according to the formula specified in each standard method.

7.2 dealing with the test results, each shall be calculated by the following statistics.

a) according to formula (1) determine the arithmetic mean x0.