scholarly journals Investigation of the fiber saturation point of tropical Brazilian wood species

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5379-5387
Author(s):  
Tiago H. Almeida ◽  
Diego H. Almeida ◽  
Vinicius B. M. Aquino ◽  
Eduardo Chahud ◽  
Roberto V. Pinheiro ◽  
...  
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
Wood Specimen ◽  
Basic Density ◽  
Fiber Saturation Point ◽  
Coefficient Of Determination ◽  
Saturation Point ◽  
Fiber Saturation ◽  
Standard Code ◽  
Brazilian Standard

The fiber saturation point (FSP) is an important parameter of wood material, related to dimensional stability and variations of mechanical performance. This paper investigated the FSP values of 15 tropical Brazilian wood species covering all strength classes of the Brazilian standard code. An additional goal was to estimate FSP value based on the wood’s apparent density. The FSP values were determined by measuring the wood specimen dimensions during moisture content reduction from the saturated state. Wood densities at 0% and 12% moisture contents and basic density were determined according to the Brazilian standard code. The average FSP for all wood species was 21.6% moisture content. Among density values, good correlations were observed, and a multivariate regression model for FSP estimation based on wood densities presented a coefficient of determination equal to 13.07%. There was no correlation between FSP and wood densities, suggesting that this parameter is almost constant regardless of the wood species.

Influence of Moisture Content in some Mechanical Properties of Two Brazilian Tropical Wood Species

2014 ◽  
Vol 1025-1026 ◽  
pp. 42-45 ◽  
Author(s):  
Luiz A. Melgaço N. Branco ◽  
Eduardo Chahud ◽  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr ◽  
Rosane A.G. Battistelle ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Moisture Content ◽  
Analysis Of Variance ◽  
Wood Species ◽  
Modulus Of Elasticity ◽  
Modulus Of Rupture ◽  
Tropical Wood ◽  
Fiber Saturation ◽  
Brazilian Standard

This study aimed, with the aid of analysis of variance (ANOVA), to investigate and quantify the influence of moisture ranging between 12% and over 30% (fiber saturation) on the mechanical properties: strength and modulus of elasticity in compression and in tension parallel to grain; modulus of rupture and modulus of elasticity in static bending; shear strength parallel to grain considering wood species Ipê (Tabebuia sp) and Angelim Araroba (Vataireopsis araroba). Tests were performed according to the assumptions and calculating methods Brazilian standard ABNT NBR 7190, Anexx B, totalizing 400 tests. Results of ANOVA revealed a significant reduction (16% on average) for mechanical properties wood due to the increase in moisture content from 12% to over 30% (fiber saturation). The same behavior also occurred when assembly containing the two species was considered.

Experimental Data Correction of the Dynamic Elastic Moduli, Velocity and Density of Solid Wood as a Function of Moisture Content above the Fiber Saturation Point

Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 309-314 ◽  
Author(s):  
Song-Yung Wang ◽  
Shih-Tzu Chuang
Keyword(s):  
Moisture Content ◽  
Wave Velocity ◽  
Stress Wave ◽  
Elastic Moduli ◽  
Free Water ◽  
Fiber Saturation Point ◽  
Saturation Point ◽  
Static Tests ◽  
Simulation Procedure ◽  
Fiber Saturation

Summary Experimentally it was observed that the dynamic modulus of elasticity calculated from the velocity of stress wave or ultrasonic wave and the density of wood in green condition increased with increasing moisture content. This statement disagrees with the physical meaning of data observed with static tests, namely the decreasing of all mechanical properties of wood with increasing moisture content. To elucidate this discrepancy a simulation procedure was developed to study the effect of free water, present in wood above the fiber saturation point on wave velocity. For this purpose the coefficient k, related to the mobility of free water was defined, as a ratio of free water vibrating simultaneously with water present in cellular wall (k = 0.6 for stress wave velocity and k = 0.7 for ultrasonic velocity). The simulation procedure using corrected values of velocity and density showed that the elastic moduli are relatively constant above the FSP, as all the mechanical parameters determined with static tests.

The Adjusted Dynamic Modulus of Elasticity Above the Fiber Saturation Point in Taiwania Plantation Wood by Ultrasonic-Wave Measurement

Holzforschung ◽  
2003 ◽  
Vol 57 (5) ◽  
pp. 547-552 ◽  
Author(s):  
S.-Y. S.-Y.Wang ◽  
C.-J. Lin ◽  
C.-M. Chiu
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Ultrasonic Wave ◽  
Ultrasonic Velocity ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Fiber Saturation Point ◽  
Saturation Point ◽  
Fiber Saturation ◽  
Dynamic Modulus Of Elasticity

Summary In this study, the effects of moisture content and bulk density on the ultrasonic velocity of Taiwania (Taiwania cryptomerioides Hay.) plantation wood in the longitudinal and radial directions are investigated. The dynamic modulus of elasticity is adjusted above the fiber saturation point by a simple method. It was observed that ultrasonic velocity tended to increase with a decrease in moisture content, and the effect of moisture content on the ultrasonic speed below the fiber saturation point was stronger than that above. Moreover, for this species ultrasonic speed in the longitudinal direction decreased with increasing bulk density, while that in the radial direction increased. The correlations between ultrasonic velocity, moisture and bulk density could be represented by a polynomial regression model. The K value for ultrasonic wave was affected by density. The adjusted dynamic modulus of elasticity remained fairly constant above the fiber saturation point using this simple method. Therefore, the results obtained by the ultrasonic-wave technique should be adjusted before estimating some physical properties of standing trees.

scholarly journals Determination of fiber saturation point of rattan (Calamus simplicifolius) using the LF-NMR and two conventional methods

2020 ◽  
Vol 54 (3) ◽  
pp. 667-682
Author(s):  
Limei Yang ◽  
Genlin Tian ◽  
Shumin Yang ◽  
Lili Shang ◽  
Xing’e Liu ◽  
...  
Keyword(s):  
Fiber Saturation Point ◽  
Saturation Point ◽  
Fiber Saturation ◽  
Conventional Methods ◽  
Calamus Simplicifolius ◽  
Lf Nmr

Moisture in softwoods: fiber saturation point, hydroxyl site content, and the amount of micropores as determined from NMR relaxation time distributions

Holzforschung ◽  
2013 ◽  
Vol 67 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Ville-Veikko Telkki ◽  
Miikka Yliniemi ◽  
Jukka Jokisaari
Keyword(s):  
Melting Point ◽  
Relaxation Times ◽  
Bound Water ◽  
Nmr Relaxation ◽  
Free Water ◽  
Bulk Water ◽  
Fiber Saturation Point ◽  
Saturation Point ◽  
Fiber Saturation ◽  
Nmr Relaxation Times

Abstract Distributions of nuclear magnetic resonance (NMR) relaxation times provide detailed information about the moisture absorbed in wood. In this work, T2*, T2, and T1 distributions were recorded from fresh sapwood and heartwood samples of pine (Pinus sylvestris) and spruce (Picea abies) at various temperatures. Below the melting point of bulk water, free water is frozen and its signal disappears from the distributions. Then, the low-temperature distributions of the unfrozen bound water contain more information about its components, because the large free water peaks hiding some smaller bound water peaks are absent and the exchange between free and bound water is prevented. Comparison of the total moisture signal integrals above and below the bulk melting point enables the determination of fiber saturation point (FSP), which, in this context, denotes the total water capacity of cell wall. T2*, T2, and T1 distributions offer different kinds of information about moisture components. All the peaks in the distributions were assigned, and it was demonstrated that the accessible hydroxyl site content and the amount of micropores can be estimated based on the peak integrals.

Sign in / Sign up

Export Citation Format

Share Document