Prediction of modulus of elasticity in static bending and density of wood at different moisture contents and feed rates by drilling resistance measurements

Sharapov, Evgenii; Brischke, Christian; Militz, Holger; Смирнова, Е. В.

doi:10.1007/s00107-019-01439-2

Cited by 23 publications

(12 citation statements)

References 24 publications

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“…Profiles in turn may be affected by moisture content (Isik & Li 2003;Lin et al 2003) which increases drilling resistance (Kahl et al 2009). However, in the case of small conditioned wood specimens, the effect of moisture content above fibre saturation (~32% MC) was not evident (Sharapov et al 2019b). Air temperature (Ukrainetz & O'Neill 2010) and wood properties such as reaction wood, resin pockets, and branches/knots, can also affect the profiles (Eckard et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Wood density estimates of standing trees by micro-drilling and other non-destructive measures

Todoroki

Lowell

Filipescu

2021

NZJFS

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Background: Accurate estimates of wood density are needed by the forest sector to increase value along the tree-to-product value-chain. Amongst tools supporting in-situ assessments, micro-drills and acoustic hammers have become increasingly popular. Our objective was to use these tools, and other easily-obtained measures, to develop predictive wood density models for in-situ assessments of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees in western North America. Methods: Wood density estimates of 133 trees, 60–75 years-old, were benchmarked against X-ray densitometry data using linear mixed-effects models. Mean resistograph amplitude (unadjusted, adjusted, and standardised variants), and combinations of acoustic velocity, tree diameter, stand age, and site index were considered as fixed effects. Plots, comprising differing treatments, and sites were considered as random effects. Candidate models were selected based on fit statistics, and further evaluated with an independent external dataset comprising 37 Douglas-fir trees. Results: The optimal model comprised amplitude (adjusted), site index (transformed), and the quotient of velocity and age. It had a mean absolute percentage error, MAPE, of 4.1%, mean absolute error, MAE, of 19.4 kg.m-3, a root-mean-squared-error, RMSE of 25.0 kg.m-3, and marginal R2 for fixed effects, R2marg of 0.60. With external data, MAPE was 8.7%, MAE 52.4 kg.m-3 and RMSE 59.5 kg.m-3. Fit statistics for a simpler two-variable model (standardised amplitude and transformed site index) were: MAPE 4.9%, MAE 23.2 kg.m-3, RMSE 28.0 kg.m-3, and R2marg, 0.48, and with external data MAPE was 8.5%, MAE 51.6 kg.m-3 and RMSE 59.3 kg.m-3. Thus, with external data, the simpler model produced greater accuracy than the optimal model. Amplitude, and all other single-variable models, recorded poorer levels of accuracy. Conclusions: Micro-drilling alone, though highly significant as a predictor, is insufficient for providing accurate wood density estimates of individual trees. Site effects need to be considered too. Standardisation of mean amplitudes to z-scores makes models highly portable across a range of resistance tools and operating speeds, and therefore more practical. As noted in the literature, optimal models are not necessarily best for predicting outcomes with other datasets, therefore model evaluation with external data is critical to determining how well a model will perform in practice.

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Section: Discussionmentioning

confidence: 99%

Wood density estimates of standing trees by micro-drilling and other non-destructive measures

Todoroki

Lowell

Filipescu

2021

NZJFS

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“…Owing to its higher amplitude, FR is most often used to preselect the feed rate for drill bit Type 2. However, DR is a more accurate parameter for the prediction of the density and mechanical properties of wood [24]. The expected advantages of using a drill bit with one major cutting edge were not evident.…”

Section: Mean Drilling Resistance and Feeding Resistancementioning

confidence: 99%

Assessment of Preservative-Treated Wooden Poles Using Drilling-Resistance Measurements

Sharapov

Brischke

Militz

2019

Forests

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An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles that were industrially vacuum-pressure-impregnated with a copper-based preservative (Korasit KS-M) and untreated reference poles. Both types of poles were subject to 10.5 years of in-ground exposure. Wood moisture content (MC) was measured using a resistance-type moisture meter. MC varied between 15% and 60% in the radial and axial directions in both treated and untreated poles. A higher MC was detected in the underground, top, and outer (sapwood) parts of the poles. Typical drilling-resistance (DR) profiles of poles with internal defects were analyzed. Preservative treatment had a significant influence on wood durability in the underground part of the poles. Based on DR measurements, we found that untreated wood that was in contact with soil was severely degraded by insects and wood-destroying fungi. Conversely, treated wood generally showed no reduction in DR or feeding resistance (FR). DR profiling is a potential method for the in-situ or in vitro assessment and quality monitoring of preservative treatments and wood durability. The technological benefits of using drill bits with one major cutting edge, instead of standard drill bits with center-spiked tips and two major cutting edges, were not evident. A new graphical method was applied to present DR data and their spatial distribution in the poles. Future studies should focus on the impact of preservative treatments, thermal modification, and chemical modification on the DR and FR of wood. This may further elucidate the predictive value of DR and FR for wood properties.

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“…Therefore, the micro-drilling resistance technology can be regarded as a method of tree ring micro-destructive detection. With the application of electrical recording in micro-drilling resistance equipment, research on tree rings, internal structure, density, elastic modulus, etc., has been gradually carried out by analyzing resistance signal waveforms [33][34][35][36]. The device, capable of acquiring resistance waveforms, was named Resistograph by Rinntech.…”

Section: Introductionmentioning

confidence: 99%

Research on Tree Ring Micro-Destructive Detection Technology Based on Digital Micro-Drilling Resistance Method

Zheng²,

Xing³

et al. 2022

Forests

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Micro-drilling resistance method is a widely used tree ring micro-destructive detection technology. To solve the problem that the detection signal of the analog micro-drilling resistance method has excessive noise interference and cannot intuitively identify tree ring information, this research proposes a digital micro-drilling resistance method and provides a recommended hardware implementation. The digital micro-drilling resistance method adopts the photoelectric encoder instead of ADC as the signal sampling module. Through the theoretical analysis of the DC motor characteristic, the PWM closed-loop speed control, the detection principle of the digital method is given. Additionally, the experimental equipment that can complete the detection of the digital method and the analog method simultaneously is designed to carry out comparative experiments. The experimental results show that: (1) The detection results of the digital method have a better-quality signal which can intuitively identify the tree rings. (2) The average correlation coefficient reaches 0.9365 between the detection results of the digital method and the analog method. (3) The average Signal-to-Noise Ratio (SNR) of the digital method is 39.0145 dB, which is 19.2590 dB higher than that of the analog method. The average noise interference energy in the detection result of the digital method is only 1.27% of the analog method. In summary, hardware implementation of the digital micro-drilling resistance method can correctly reflect the tree ring information and significantly improve the signal quality of the micro-drilling resistance technology. This research is helping to improve the identification accuracy of micro-drilling resistance technology, and to develop the application of tree ring micro-destructive detection technology in the high-precision field.

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Prediction of modulus of elasticity in static bending and density of wood at different moisture contents and feed rates by drilling resistance measurements

Cited by 23 publications

References 24 publications

Wood density estimates of standing trees by micro-drilling and other non-destructive measures

Wood density estimates of standing trees by micro-drilling and other non-destructive measures

Assessment of Preservative-Treated Wooden Poles Using Drilling-Resistance Measurements

Research on Tree Ring Micro-Destructive Detection Technology Based on Digital Micro-Drilling Resistance Method

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