Structural specification sawn timber grading method

Abstract

The invention discloses a structural specification sawn timber grading method which comprises the following steps: S1, performing random representative sampling on specification sawn timber; S2, sequentially labeling, weighing and measuring the moisture content of the sawn timber sample, and performing calculating to obtain the density distribution of the standard sawn timber sample; S3, measuringrelated mechanical property indexes of the sawn timber sample; S4, obtaining a linear fitting equation between the specification sawn timber mechanical property index and the density through regression calculation, namely a specification sawn timber grading model; and S5, according to the model, testing the density of the standard sawn timber offline or online by setting a density grading threshold value or a grading interval, so that grading of the standard sawn timber is completed. According to the grading method, the structural specification sawn timber grading speed is high, the cost is low, and the precision is high.

Description

technical field [0001] The invention relates to the field of manufacturing engineering wood products and green prefabricated building materials, and more specifically relates to a method for grading sawn timber with specifications for structures. Background technique [0002] With the promotion and development of modern wood structures in my country, the consumption of structural sawn timber and new engineering wood products is increasing. These new engineered wood products, such as glued laminated timber (GLT) and cross-laminated timber (CLT), are produced by grading dry sawn timber and then rationally forming billets. Sawn timber grading is generally divided into two types: appearance grading and stress grading. Appearance grading is mainly based on defects on the surface of sawn timber, such as missing edges, knots, cracks, bending and decay, etc., while stress grading is generally based on the measurement of the elastic modulus of sawn timber. Improving the quality of ...

AI Technical Summary

Problems solved by technology

However, the above-mentioned methods all need special equipment, and the required equipment is expensive and the operation is also complicated.

Due to space and capital constraints, general enterprises have insufficient industrialization, so there are few manufacturers with standard sawn timber grading equipment

In addition, methods such as the stress wave (ultrasonic) method and the transverse vibration method have certain requirements for the size of the sawn timber. However, the sizes of the sawn timber produced in my country are various, and it is difficult to meet the requirements for use.

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