scholarly journals Application of Nondestructive Testing Technologies in Preserving Historic Trees and Ancient Timber Structures in China

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 318
Author(s):  
Pengfei Xu ◽  
Cheng Guan ◽  
Houjiang Zhang ◽  
Guanghui Li ◽  
Dong Zhao ◽  
...  
Keyword(s):  
Nondestructive Testing ◽  
Stress Wave ◽  
Digital Imaging ◽  
Visual Inspection ◽  
Wave Transmission ◽  
Theoretical Research ◽  
Timber Structures ◽  
Internal Defects ◽  
Wave Tomography ◽  
Transmission Velocity

In China, preserving historic trees and ancient timber structures has attracted more attention from researchers and institutions. Nondestructive testing (NDT) technology has gained momentum in the application and research in recent years. This paper presents some examples of the application of NDT techniques in the protection of historic trees and ancient timber structures in China. A total of nine NDT techniques were applied, including five techniques of visual inspection, sounding, Resistograph, stress wave transmission velocity, stress wave tomography for both historic trees and ancient timber structures, two techniques of the pulling-test and ground-penetrating radar (GPR) for historic trees alone, and two techniques of acoustic emission (AE) and digital imaging for ancient timber structures. Based on field testing, there is a very good detecting effect for visual inspection and Resistograph, but sounding works unsatisfactorily. The stress wave transmission velocity is found to be excellent in screening for the internal defects of historic tree trunks, but performs badly in screening for the internal defects within the wood members of ancient timber structures. AE is less successful but digital imaging performs well in long-term monitoring and damage warning of wood structures. The stress wave tomography successfully obtains images of internal defects inside tree trunks. The anchorage of some historic trees cannot be quantitatively evaluated with the pulling test if the tree is too large. GPR’s resolution and accuracy are very low, which limit its application. Theoretical research on NDT and promotion of NDT technology are still an essential part of the work in the future.

scholarly journals Minimally Invasive Detection Technologies for the Defects in Ancient Timber Structural Building

2018 ◽  
Vol 777 ◽  
pp. 476-482
Author(s):  
Pei Xuan Wang ◽  
Wei Zhang ◽  
Sheng Cai Li ◽  
Chang Yong Hu ◽  
Nicola Macchioni ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Stress Wave ◽  
Detection Method ◽  
Timber Structures ◽  
Wave Tomography ◽  
Detection Technologies

How to examine and describe the defects in timber is vital for assessing the performance of an ancient timber structural building. This paper mainly elaborates the methodology of detecting the defects in ancient timber structures. The detection method includes preliminary condition survey, stress-wave tomography test, and correction with resistographic drilling. By means of above detection, the defects inside a timber structural building could be described more accurately.

The Study of Stress Wave Tomography Algorithm for Internal Defects in RL Plane of Wood

2018 ◽  
Author(s):  
Hailin Feng ◽  
Zheng Qian ◽  
Mingyue Hu ◽  
Zeyu Zheng ◽  
Xiaochen Du
Keyword(s):  
Stress Wave ◽  
Internal Defects ◽  
Wave Tomography

scholarly journals Nondestructive Testing on Ancient Wooden Components Based on Shapley Value

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Li-hong Chang ◽  
Xiao-hong Chang ◽  
Hao Chang ◽  
Wei Qian ◽  
Li-ting Cheng ◽  
...  
Keyword(s):  
Nondestructive Testing ◽  
Stress Wave ◽  
Shapley Value ◽  
Testing Methods ◽  
Internal Defects ◽  
Forecasting Models ◽  
Defect Area ◽  
Nondestructive Testing Methods ◽  
Combined Forecasting ◽  
Impedance Meter

In this study, we propose nondestructive testing methods and combined forecasting models-based stress wave and impedance measurements to obtain accurate internal defects information for wooden building components. Internal defects data for major wooden components of an ancient building in China and reverse laboratory test data on matching tree species indicated various degrees of damage on the pavilion wood structure surface and internal defects in certain pillars. The stress wave method enabled rapid acquisition of two-dimensional plots of test sections; however, the results revealed that the area of stress wave detection was greater than the actual defect area. Moreover, the impedance meter was able to determine the defect position and type in a single path, and the actual defect area was proportional to the absolute error of the drilling resistance. By distributing the errors from the two nondestructive testing methods on the basis of a Shapley value algorithm, we determined the weights of stress wave and impedance meter data in the forecasting models and established combined forecasting models that showed greater accuracy with a mean relative error of less than 6%. This method can improve the prediction accuracy of internal defects in ancient buildings and provide effective data support for practical engineering repair and reinforcement schemes.

scholarly journals Stress Wave Tomography of Wood Internal Defects using Ellipse-Based Spatial Interpolation and Velocity Compensation

BioResources ◽  
2015 ◽  
Vol 10 (3) ◽  
Author(s):  
Xiaochen Du ◽  
Shaozhe Li ◽  
Guanghui Li ◽  
Hailin Feng ◽  
Shengyong Chen
Keyword(s):  
Stress Wave ◽  
Spatial Interpolation ◽  
Internal Defects ◽  
Wave Tomography

scholarly journals Development of Testing Platform and Comparison Studies for Wood Nondestructive Testing

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Jian Li ◽  
Yiming Fang ◽  
Jiyong Tang ◽  
Hailin Feng ◽  
Xiongwei Lou
Keyword(s):  
Nondestructive Testing ◽  
Stress Wave ◽  
Virtual Instrument ◽  
Wood Properties ◽  
Time Interval ◽  
Peak Time ◽  
Testing Platform ◽  
Time Interval Measurement ◽  
Nondestructive Testing Methods

Stress wave based techniques have been developed for evaluating the quality of the wooden materials nondestructively. However the existing techniques have some shortcomings due to the significant variation of the wood properties and are now in need of updating. There are also stress wave based instruments which have been widely used for nondestructive testing of wood. But most of them are inflexible and unsuitable for the tentative studies. This paper proposed and implemented a wood nondestructive testing platform based on NI virtual instrument. Three wood nondestructive testing methods, including peak time interval measurement, cross-correlation, and spectrum analysis, were also tested on this platform with serious decay sample, early decay sample, and defect-free sample. The results show that new methods can be verified easily and the researches of wood nondestructive testing will be accelerated with the designed platform.

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