A method for micro-destructive testing of flexural strength of fragile wooden cultural relics

A technology for flexural strength and wood, which is applied in the field of micro-damage testing of the flexural strength of fragile wooden cultural relics, which can solve the problems that it is difficult to apply decayed archaeological wood, the load of the test instrument is large, and the sample volume is large, so as to achieve high sensitivity and accuracy , Simple sample preparation, high precision effect

Active Publication Date: 2022-07-22
UNIV OF SCI & TECH BEIJING +1
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  • Abstract
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  • Claims
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Problems solved by technology

[0005] In order to solve the problems that the existing testing methods for mechanical properties of wood require large sample size and sample volume, large test instrument load, low precision, and difficulty in applying to decayed archaeological wood, the present invention provides a micro-damage testing method for bending resistance of fragile wooden cultural relics. The strength method, that is, using a static thermomechanical analyzer, only a small amount of thin slice samples can effectively test the flexural strength of most archaeological wooden cultural relics in different preservation conditions. It has a wide range of applications, high precision and good repeatability of test results

Method used

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  • A method for micro-destructive testing of flexural strength of fragile wooden cultural relics
  • A method for micro-destructive testing of flexural strength of fragile wooden cultural relics
  • A method for micro-destructive testing of flexural strength of fragile wooden cultural relics

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Effect test

Embodiment 1

[0052] The bending strength of the "Nanhai No. 1" shipwreck scattered wood samples was tested by bending experiments. The wood species is Chinese fir, which is mild to moderate degradation, and the maximum moisture content is 331%. The samples were cut into standard strips (8 mm x 2 mm x 0.3 mm) and dried naturally. Measure the span L of the fixture is 5mm, the width b of the sample is 2.299mm, and the thickness d is 0.244mm; place the wooden strip on the three-point bending fixture, the position is as follows figure 2 shown. Start the test at room temperature, lower the probe, set the initial load to 5mN, and increase it uniformly at 5mN / min. After 30min, the sample breaks, record the change curve of displacement and load with time; L, sample width b, thickness d, real-time displacement D, real-time load P into the formula The stress σ of the specimen is obtained f , sample strain ε f , make a stress-strain curve; the instantaneous stress of the sample fracture is the...

Embodiment 2

[0054] The bending strength of the "Nanhai No. 1" shipwreck's bulkhead was tested by bending experiments. The wood species is hardwood pine, which is moderately degraded and has a water content of 452%. The samples were cut into standard strips (8 mm x 2 mm x 0.3 mm) and dried slowly. The span L of the fixture is measured to be 5mm, the width b of the sample is 1.885mm, and the thickness d is 0.172mm; the wooden strip is placed on the three-point bending fixture, the test is started at room temperature, the probe is lowered, the initial load is set to 2mN, and the 5mN / min increased uniformly, the sample broke after 10min, and the change curve of displacement and load with time was recorded, such as Figure 5 The data obtained from the experiment are processed, and the fixture span L, sample width b, thickness d, real-time displacement D, real-time load P are substituted into the formula The stress σ of the specimen is obtained f , sample strain ε f , make the stress-strain...

Embodiment 3

[0056] The bending strength of the wooden components of the "Nanhai No. 1" shipwreck was tested through the bending test. The wood species is sweetgum, which is moderately to severely degraded, and the maximum moisture content is 472%. The sample was cut into standard splines (8mm×2mm×0.3mm) and dried slowly. The span of the fixture was measured to be 5mm, the width of the sample to be b, and the thickness of the sample to be d. Start the test at room temperature, lower the probe, set the initial load to 1mN, and increase it uniformly at 2mN / min. After 12min, the sample breaks, and record the change curve of displacement and load with time; process the data obtained from the experiment, set the clamp span L , sample width b, thickness d, real-time displacement D, real-time load P into the formula The stress σ of the specimen is obtained f , sample strain ε f , make a stress-strain curve; the instantaneous stress of the sample fracture is the bending strength of the sample σ...

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Abstract

The invention relates to the field of detection of wooden cultural relics, and discloses a method for micro-loss testing the bending strength of fragile wooden cultural relics. The method includes: cutting the sample into standard splines; measuring the span between the fixtures, the width and thickness of the standard splines, reading and recording the values; placing the standard splines on the fixtures to start the test, and applying uniform pressure to the standard splines. Increase the load until the standard spline is pressed to break, measure the relationship between the displacement and pressure of the standard spline, and record the curve of displacement and load with time; , Real-time load to obtain the stress and strain of the standard spline, and draw the stress-strain curve; the instantaneous stress of the standard spline fracture is the flexural strength of the standard spline. The invention can effectively test the flexural strength of most archaeological wooden cultural relics in different preservation conditions only with a small amount of thin slice samples, has a wide range of applications, and has high test result accuracy and good repeatability.

Description

technical field [0001] The invention relates to the technical field of cultural relics testing, in particular to a method for micro-loss testing the flexural strength of fragile wooden cultural relics. Background technique [0002] Wooden cultural relics are an important part of my country's splendid cultural heritage, and are precious physical materials for the study of ancient technology, art and culture. In the protection research of large-scale water-saturated wooden cultural relics such as shipwrecks, coffins, and wood carvings, it is of great significance to accurately characterize their mechanical properties, and it is an important basis for evaluating the preservation status of cultural relics, grading the degree of disease and formulating protection plans. However, after prolonged underground / underwater burial and microbial degradation, cellulose and hemicellulose in wood cell walls are partially degraded, resulting in loose and porous cell walls and greatly increas...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/20
CPCG01N3/20G01N2203/0023G01N2203/0012G01N2203/0067G01N2203/0676G01N2203/0682
Inventor 韩向娜韩刘杨秦振芳吴梦若席光兰张治国
Owner UNIV OF SCI & TECH BEIJING
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