Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)

Holzforschung ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Julia K. Denzler ◽  
Andreas Weidenhiller
Keyword(s):  
Nondestructive Testing ◽  
Moisture Content ◽  
Industrial Application ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
The State ◽  
Temperature Measurements ◽  
Unfrozen Water ◽  
State Of Matter

AbstractThe possibility for pre-grading of logs throughout the year has been evaluated based on dynamic modulus of elasticity (MOEdynor simplifiedEdyn) by means of frequency-based nondestructive testing (NDTfreq). The challenge is thatEdynis variable in the frozen, partly frozen, and unfrozen states of logs (state of matter). In the unfrozen state, NDTfreqis reliable if the moisture content does not fall below fiber saturation. The state of the matter was tested via temperature measurements of air and log by means of an infrared technique and sensors, and information was evaluated from NDTfreq. The temperature measurements proved to be inefficient for industrial application because of unreliable data and long measurement times, whereas the NDTfreqmeasurements allowed the determination of meaningful damping factors. A sufficient level of predictability for more than 60% of the measurements was found. The log measurements in the partly frozen state are inconclusive becauseEdyndata fluctuate in the presence of both liquid and frozen water. For the completely frozen logs, a correction is introduced as a precaution that avoids an overestimation ofEdynin the unfrozen state.

ANALYSIS OF SOUND SPEED IN LONGITUDINAL DIRECTION AT REFERENCE MOISTURE CONTENT (w = 12 %) IN SAWMILL ASSORTMENTS (FAGUS SYLVATICA, L.)

Akustika ◽  
2020 ◽  
pp. 45-50
Author(s):  
Alena Rohanová
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Sound Speed ◽  
Longitudinal Direction ◽  
Structural Timber ◽  
Sound Speeds ◽  
Dynamic Modulus Of Elasticity ◽  
Round Timber

This paper explores the analysis of sound speeds in the longitudinal direction and their reduction to the reference moisture content w = 12 %. The sound speed cw was determined with Sylvatest Duo device. Moisture content of beech sawmill assortments (round timber: N = 16, logs: N = 2 × 16, structural boards: N = 54) in the range of 12 – 72 % was measured. For the analysis purposes, the sound speed was converted to reference conditions (c12, uref = 12%). A second-degree polynomial (parabola) with a regression equation of the form: c// = 5649 - 27,371 × w + 0.0735 × w2 was used to convert cw to c12, and correction of measured and calculated values was used as well. The sound speeds c12 in sawmill assortments (c12,round, c12,log, c12,board) were evaluated by linear dependences. Dependence was not confirmed for c12,round and c12,board1 (r = 0.168), in contrast for c12,round and c12,log2 the dependence is statistically very significant (r = 0.634). The results of testing showed that the most suitable procedure for predicting quality of structural timber is the first step round timber – log2, the second step: log2 - board2. More exact results of the construction boards were obtained from log2 than from log1. The sound speed is used in the calculation of dynamic modulus of elasticity (Edyn). EN 408 mentions the possibility of using dynamic modulus of elasticity as an alternative method in predicting the quality of structural timber.

scholarly journals Determination of elastic parameters of grain with oedometric and acoustic methods

2012 ◽  
Vol 49 (No. 2) ◽  
pp. 56-60 ◽  
Author(s):  
M. Stasiak
Keyword(s):  
Hydrostatic Pressure ◽  
Moisture Content ◽  
Shear Wave ◽  
Equilibrium Moisture Content ◽  
Shear Wave Velocity ◽  
Modulus Of Elasticity ◽  
Uniaxial Compression Test ◽  
Elastic Parameters ◽  
Acoustic Methods

Values of modulus of elasticity E and Poisson’s ratio   were determined with two methods adopted from geotechnique. First approach used was a method proposed by Sawicki (1994). This type of examination was applied to estimate values of E and v for wheat and rapeseed beddings for five levels of moisture content ranging from 6% to 20%. Modulus of elasticity E of wheat was found to decrease with an increase in moisture content. With the second method values of E were determined based on measurement of shear wave velocity. Tests were performed for bedding of wheat and rapeseed under equilibrium moisture content. Values of modulus of elasticity were found to depend of hydrostatic pressure and were higher then those determined in uniaxial compression test.

Pulse Method Used for Non-Destructive Assessment of Glued Laminated Timber Beams

2016 ◽  
Vol 827 ◽  
pp. 231-234 ◽  
Author(s):  
Pavel Klapálek ◽  
Lenka Melzerová ◽  
Tomáš Plachy
Keyword(s):  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Pulse Method ◽  
Dynamic Modulus Of Elasticity ◽  
Glued Laminated Timber ◽  
Non Destructive ◽  
Timber Beams ◽  
The Way

This text is focused on GLULAM (glued laminated timber) beams and determination of their properties. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on pulse method, which is used to determine the dynamic modulus of elasticity of GLULAM beams. This text will describe how the pulse method works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.

Relativity Analysis between Dynamic and Static Modulus of Elasticity on Different Thickness Wood-Plastic Structural Plates

2011 ◽  
Vol 121-126 ◽  
pp. 4254-4258 ◽  
Author(s):  
Gui Wen Yu ◽  
Ying Cheng Hu ◽  
Ji You Gu
Keyword(s):  
Mechanical Properties ◽  
Nondestructive Testing ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Bending Test ◽  
Three Point Bending ◽  
Static Modulus ◽  
Dynamic Modulus Of Elasticity ◽  
Static Modulus Of Elasticity ◽  
Different Thickness

The relativity was evaluated between dynamic modulus of elasticity (MOE) and static MOE, in order to assess the potential of using nondestructive testing (NDT) method as a checking tool for mechanical properties of wood-plastic structural plates. The dynamic MOE was evaluated on a FFT system, and the static MOE was determined by three point bending test. All of specimens were made of polyethylene（PE）and poplar flour. A significant correlation between the dynamic MOE and the static MOE was obtained from relativity analysis. These results suggest that the NDT method could be appropriate to estimate the dynamic MOE of specimens with different thickness.

scholarly journals Influence of the moisture content on the dynamic modulus of elasticity of concrete made with recycled aggregate

2019 ◽  
Vol 19 (2) ◽  
pp. 79-89
Author(s):  
Claudio de Souza Kazmierczak ◽  
Joana Kirchner Benetti Boaro ◽  
Monique Palavro Lunardi ◽  
Marlova Piva Kulakowski ◽  
Mauricio Mancio
Keyword(s):  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Coarse Aggregates ◽  
Codes Of Practice ◽  
Dynamic Modulus Of Elasticity

Abstract The elastic behavior of the concrete is estimated from its strength or determined by static or dynamic tests. However, because the codes of practice do not standardize the internal moisture content of the concrete and disregard the use of recycled aggregates when proposing equations for the estimation of the modulus of elasticity, discrepancies between the values measured and estimated are frequent. The influence of the moisture content of concrete containing basaltic coarse aggregates and coarse recycled concrete aggregate in the dynamic modulus of elasticity is discussed in this paper. A basalt coarse aggregate and two recycled coarse aggregates where used. For each type of coarse aggregate, concrete with compression strength between 25 MPa and 55 MPa were produced. The dynamic modulus of elasticity of the saturated samples were determined and range from 26 GPa to 46 GPa. There is a significant difference in the value of the dynamic modulus of elasticity for dry concrete versus saturated concrete, also influenced by the type of aggregate. Estimations of the modulus of elasticity from the compressive strength equations proposed by the codes of practice must be improved considering its characteristics.

Estimation of Elastic Constants of Restoration Mortars, Used on Historic Masonries Restoration Interventions, VIA Ultrasonic Technique and Correlation to their Mechanical and Microstructure Parameters

2004 ◽  
Vol 852 ◽  
Author(s):  
Antonia Moropoulou ◽  
Asterios Bakolas ◽  
Eleni Aggelakopoulou ◽  
Anastasia Odatzidou ◽  
Christos Teas ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Pore Radius ◽  
Capillary Rise ◽  
Microstructural Characteristics ◽  
Average Pore ◽  
Average Pore Radius ◽  
Cumulative Volume

ABSTRACTEight syntheses of mortars used for restoration interventions in historic masonry were produced using the traditional materials of aerial lime and artificial pozzolanic additives. The mortars were aged over a 15-month period and then tested for properties related to chemical and mechanical stabilization using the following four analytical techniques: ultrasonic velocity propagation and the mortars' dynamic modulus of elasticity (Ed), mercury intrusion porosimetry for evaluation of microstructural characteristics (percentage open porosity, bulk density, average pore radius, total cumulative volume, and specific surface area), water capillary rise tests for the determination of total cumulative volume accessible to water and capillary rise coefficients of the mortars, and conventional mechanical tests for the determination of the mortars' flexural and compressive strength. Performance is correlated to the mortars' chemical composition, microstructural characteristics (as measure by average pore radius) and mechanical characteristics as measured by dynamic modulus of elasticity (Ed) and flexural and compressive strength (Fc).

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