Static Bending Modulus Of Elasticity Research Articles

Estimation of the static bending modulus of elasticity in glulam elements by ultrasound and modal-updating NDT techniques

Glulam timber is gaining popularity as a structural element due to its cost-effectiveness, strength, and environmental benefits. However, being an organic material, it is susceptible to degradation. Therefore, nondestructive testing (NDT) methods are essential for assessing its structural health. In this study, two NDT approaches, ultrasound-based and modal updating, were used to predict the static bending modulus of elasticity (MOE) in Pinus Sylvestris and Spruce species. The results demonstrated that the modal updating and linear regression models outperformed the ultrasound technique in accurately determining the static MOE. Additionally, considering the influence of knots improved the accuracy of ultrasound predictions.

Mechanical Properties Evaluation of Eucalyptus grandis Wood at Three Different Heights by Impulse Excitation Technique (IET)

Wood is a natural material with great variability in its mechanical properties. This study analyzed the effectiveness of the impulse excitation technique (IET) to characterize the stiffness of 10-year-old Eucalyptus grandis wood at three different heights of 3 m, 6 m, and 9 m from the bottom (height A, B, and C, respectively). A nondestructive testing method—excitation impulse, using Sonelastic® PC-based technology—and a destructive static bending test were used. The mean value for the modulus of elasticity (MOE) in bending was 16.4 GPa and in IET the value was 16.6 GPa. The average values for MOE in static bending were 14.8 GPa at height A, 17.9 GPa at height B, and 17.0 GPa at height C, demonstrating that the greater the height in the trunk of the tree the greater its modulus of elasticity. The correlation equation between static MOE and dynamic MOE was MOESTAT = 0.743.MOEDYN + 4.0983, with the coefficient of determination of R² = 0.85.

Relationships between Static Mechanical Properties and SilviScan Measured Wood Properties in Loblolly Pine

AbstractRelationships between static bending modulus of elasticity (MOE) and SilviScan (SS) properties (SilviScan MOE [MOESS], specific gravity, and microfibril angle) were explored. Seventy-three clearwood specimens (25 by 25 by 406 mm) were cut from thirty-two 33-year-old loblolly pine trees. Relationships were calculated between MOE and MOESS (R2 = 0.77); however, MOESS, calibrated using sonic resonance, averaged 25 percent higher than static MOE. Calibrating MOESS to static MOE instead of sonic resonance MOE resulted in similar prediction performance (R2 = 0.77), but more importantly approximately equal prediction values. The results demonstrate the importance of properly utilizing SilviScan information for predicting loblolly pine properties in static bending.

Modeling and experimental validation of elastic modulus of Pinus yunnanensis exposed to high relative humidity

Wood as a renewable engineering material has widely been used for structural purpose for decades, but its static bending modulus of elasticity (Eb) has not been seriously researched in large-scale relative humidity fluctuant environment. This paper presents an experimental and numerical study for the assessment of Eb of Pinus yunnanensis as a function of moisture content and its distribution in high relative humidity environment. For this, a moisture transfer model based on a multi-phase-type approach and a classical theory of laminated plate was used. The experimental results indicated that the predicted Eb had good agreement with measured data making it possible for researchers, designers, and industry in the field of wood mechanics and products to directly obtain the wood Eb by way of calculation. Furthermore, it was also found that there was a decrease in Eb in the short term when the environment relative humidity increased substantially. This phenomenon reminds designers and industry in the field of wood mechanics and products that using so-called Eb with equilibrium moisture content as the actual mechanical value of structural-use wood may bear a potential risk.

Evaluation of Maximum Strength and Modulus of Elasticity of Douglas-Fir Lumber in Axial to Grain Tension by Two Nondestructive Techniques

Modulus of elasticity (MOE) of Douglas-fir ( Pseudotsuga menziesii) lumber loaded in parallel to grain tension was evaluated by nondestructive techniques (transverse vibration and longitudinal stress wave) and the results were correlated to the actual properties. Nondestructive parameters of specific gravity, wave frequency and attenuation and wave speed were measured. Destructive tests were performed with the use of static tension and bending techniques. Regression analyses were performed to correlate all nondestructive and destructive techniques. Results showed the MOE in static bending can be predicted with good efficiency. The correlation coefficients (R) for this test ranged from 0.818 to 0.941. The maximum tensile strength presented a poor correlation to the nondestructive parameters with the highest R=0.582.

Effects of grading of veneers on properties of LVL made from Schizolobium amazonicum Huber ex. Ducke

The work aimed at evaluating the influence of pre-classification of veneer made from parica (Schizolobium amazonicum Huber ex. Ducke) plantation trees on Laminated Veneer Lumber (LVL) properties. This species is native to the Amazonian and is fast growing with low density. For LVL production, veneers were separated into four classes according to the density or dynamic modulus of elasticity. LVL was produced considering three different strategies of assembly—random veneers assembly; assembly using veneers with greater EMd placed at the surface layer with gradual reduction up to the center of the panels; assembly using veneers with greater density placed at the surface layer and gradual reduction into the center of the panels. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (EM), modulus of rupture (fM), compression strength parallel to grain (fc0), shear strength parallel to glue-line (fv0), shear strength perpendicular to glue-line (fv90), water absorption and thickness swelling for 2 and 24 h of water immersion. Physical properties of LVL were not found to be influenced by different pre-classification strategies, while for mechanical properties only bending strength at flatwise position was influenced by pre-classifying veneers.

Influence of Adhesive Type on the Properties of LVL Made from Paricá (Schizolobium amazonicum Huber ex. Ducke) Plantation Trees

The work aimed at evaluating the infl uence of the adhesives on physical and mechanical properties of laminated veneer lumber (LVL) boards made from Schizolobium amazonicum plantation trees. This species is native from Amazonia and it is showing fast growing and low density. LVL was produced in three different treatment groups considering the type of adhesive used (Polyvinyl Acetate Crosslinking – PVAc, phenol-formaldehyde – PF and polyurethane – PU). For each treatment, pieces with dimensions of 25 cm x 2.2 cm x 50 cm were produced. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (EM), modulus of rupture (fM), compression strength parallel to grain (fc,0), shear strength parallel to glue-line (fv,0), shear strength perpendicular to glue-line (fv,90), water absorption and thickness swelling for 2 and 24 h of water immersion. The adhesives used in this study signifi cantly infl uenced the performance of LVL. Polyurethane adhesive presented better results with respect to physical properties. Phenol-formaldehyde provided greater resistance among the adhesives tested.

탄화온도별로 제조된 거대억새 세라믹의 비파괴 휨강도 평가

공진주파수 모드를 이용하는 비파괴 평가기술법을 거대억새 파티클 보드를 페놀수지로 함침한 후 탄화온도별(600, 800, 1000, <TEX>$1200^{\circ}C$</TEX>)로 제조한 세라믹에 적용하였다. 동적 탄성계수와 정적 휨 탄성계수는 탄화온도가 증가할수록 증가하였다. 휨 강도에 대한 동적 탄성계수 및 정적 휨 탄성계수는 밀접한 상관관계를 나타내었다. 그러나 휨 강도에 대한 상관관계에서 정적 탄성계수 보다 동적 탄성계수가 더 밀접한 상관관계를 나타내었다. 따라서 공진 주파수 모드를 사용하는 동적 탄성계수측정법으로 소성온도에 따라 제조된 거대억대 파티클보드의 휨 강도를 예측하는 비파괴 평가 방법으로 유용할 것으로 판단된다. Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for ceramics made by different carbonizing temperatures (600, 800, 1000, <TEX>$1200^{\circ}C$</TEX>) after impregnating the phenol resin with Miscanthus sinensis var. purpurascen particle boards. Dynamic modulus of elasticity increased with increasing carbonizing temperature. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to modulus of rupture (MOR). However, the result indicated that correlation coefficient was higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of ceramics made by different carbonizing temperature for Miscanthus sinensis var. purpurascens particle boards.

Effects of Steaming, Drying Temperature, and Adhesive Type on Static Bending Properties of LVL made of Picea orientalis and Abies nordmanniana veneers

The modulus of elasticity (MOE) and modulus of rupture (MOR) were evaluated for laminated veneer lumber (LVL) in static bending. The studied species were spruce (Picea orientalis) and fir (Abies nordmanniana) originated from the Eastern Black sea region and prepared with phenol-formaldehyde and melamine-urea-formaldehyde. The effect of wood species, steaming, drying temperature, and type of adhesive on static bending MOE and MOR were determined. According to the experimental results, the bending strength of spruce wood (Maçka) treated with phenol formadehyde adhesives is the highest for the specimens steamed for 6 h at a drying temperature of 110 ºC. Furthermore, the modulus of elasticity for spruce wood (Maçka) treated with phenol formadehyde adhesive is the highest for the specimens steamed for 12 h and subjected to a drying temperature of 150 ºC.

Nondestructive Bending Strength Evaluation of Ceramics Made from Miscanthus sinensis var. purpurascens Particle Boards - Effect of Resin Impregnation Ratio -

Nondestructive evaluation (NDE) method by using a resonance frequency mode was carried out for ceramics made from particle boards with different phenol resin impregnation ratios (30, 40, 50, 60%) at carbonizing temperature of <TEX>$800^{\circ}C$</TEX>. The material for ceramics was Miscanthus sinensis var. purpurascens board. Dynamic modulus of elasticity increased with increasing impregnation ratio. There was a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to modulus of rupture (MOR). However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of ceramics made from Miscanthus sinensis var. purpurascens particle boards by different phenol resin impregnation ratios.

&lt;b&gt;Evaluation of modulus of elasticity in static bending of particleboards manufactured with &lt;i&gt;Eucalyptus grandis&lt;/i&gt; wood and oat hulls

The aim of this study was to determine the modulus of elasticity (MOE) in static bending using two different calculation methods, a simple one based on Brazilian standard ABNT NBR 14810 (ABNT, 2006), and an alternative one, based on the Least Squares Method, and evaluate whether there is statistical equivalence between these MOE calculation methods. The alternative method employed results obtained from static bending tests at three-points, with three dial gauges, non-destructively, by imposing limits on two displacements (L 300 -1 and L 200 -1 ), where L is the specimen length. Results of confidence intervals indicated statistical equivalence between MOE values obtained by means of both methods, thus corroborating the simple mathematical model proposed by ABNT NBR14810 (ABNT, 2006). Panels produced with up to 15% oat hulls (Treatments 1 to 6) showed the highest average MOE values. The methods employed to obtain MOE in static bending were statistically equivalent. However, in addition to being non-destructive, the alternative method proposed here in provided more reliable results, just by taking into account more measures along the specimens.

Nondestructive Evaluation of Strength Property for Damaged Black Pine Wood(Pinus thunbergii) by Matsucoccus thunbergianae Using Free Vibration Mode

Nondestructive evaluation (NDE) technique method using a resonance frequency by free vibration mode was carried out for damaged and sound black pine woods( Pinus thunbergii ) by Matstucoccus thunbergianae in order to utilize damaged trees. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR in all conditions. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by free vibration mode is more useful as a nondestructive evaluation method for predicting the MOR of sound and damaged woods by Matstucoccus thunbergianae.

Influence of veneer thickness on the properties of LVL from Paricá (Schizolobium amazonicum) plantation trees

The work aimed at evaluating the influence of the veneer thickness on physical and mechanical properties of laminated veneer lumber (LVL) boards made from Schizolobium amazonicum plantation trees. It is a fast growing species (20 m3/ha/year), having a straight trunk almost without any branch and producing a white-yellowish low density hardwood: usually <0.40 g/cm3. The boards were manufactured with the following thicknesses: 1.54, 2.32 and 2.71 mm. Seven LVL boards were produced for each thickness, totaling 21, all according to the following characteristics: PVAc adhesive (200 g/m2), pressed (1.0 N/mm2) at room temperature for 12 h. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (EM), modulus of rupture (fM), compression strength parallel to grain (fc,0), shear strength parallel to glue-line (fv,0), shear strength perpendicular to glue-line (fv,90), water absorption and thickness swelling for 2 and 24 h of water immersion. The results pointed out that the utilization of thinner veneers implied improving mechanical properties, while thicker veneer reduced the water absorption. Nevertheless, in contrast, the efficiency was lower than that observed when thicker veneer was used.

Nondestructive Evaluation of Strength Performance for Heat-Treated Wood Using Impact Hammer &amp; Transducer

Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for heat-treated wood under different conditions. The effect of heat treatment on the bending strength and NDE technique using the resonance frequency by impact hammer and force transducer mode for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at <TEX>$175^{\circ}C$</TEX> and <TEX>$200^{\circ}C$</TEX>, respectively. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. In all conditions, It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by impact hammer mode is more useful as a nondestructive evaluation method for predicting the MOR of heat-treated wood under different temperature and species conditions.

Graphical Analysis of Static and Dynamic Elastic Modulus of Shaving Sheet

The traditional measurement method of thin wood-based panel’s elastic modulus is carried out on the test piece for three-point or four-point bending static deformation test, the determination process is complex, time consuming, and makes damage to specimen. Use materials mechanics quick measuring instrument of sheet board wood, which is self-developed and based on the principle of cantilever’s free vibration and cantilever bending to test three standards of thin wood-based panels’ and medium density fiberboard’s dynamic modulus of elasticity and static bending elastic modulus, use SPSS (Statisti-cal Program for Social Sciences) software to establish the relationship graphics of sheet’s dynamic and static bending modulus of elasticity, relationship graphics of dynamic bending and three-point bending elastic modulus, and use linear regression to do correlation analysis on measurement results, while taking advantage of three-point bending to measure same test pieces’ three-point bending modulus of elasticity to compare and authenticate. The results show that: the average of cantilever vibration dynamic elastic modulus is higher than cantilever bending static elastic modulus, and there is a very significant linear correlation between them; cantilever vibration dynamic modulus of elasticity and three-point bending modulus of elasticity have significant linear correlation, which shows that taking advantage of materials mechanics fast measuring instrument of sheet wood to measure the modulus of elasticity of thin wood-based panel and medium density fiberboard quickly.

Evaluation of Stiffness and Strength of Scots Pine Wood Using Resonance Frequency and Ultrasonic Techniques

The aim of this paper was to predict the static bending modulus of elasticity (MOES) and modulus of rupture (MOR) of Scots pine (Pinus sylvestris L.) wood using three nondestructive techniques. The mean values of the dynamic modulus of elasticity based on flexural vibration (MOEF), longitudinal vibration (MOELV), and indirect ultrasonic (MOEUS) were 13.8, 22.3, and 30.9 % higher than the static modulus of elasticity (MOES), respectively. The reduction of this difference, taking into account the shear deflection effect in the output values for static bending modulus of elasticity, was also discussed in this study. The three dynamic moduli of elasticity correlated well with the static MOES and MOR; correlation coefficients ranged between 0.68 and 0.96. The correlation coefficients between the dynamic moduli and MOES were higher than those between the dynamic moduli and MOR. The highest correlation between the dynamic moduli and static bending properties was obtained by the flexural vibration technique in comparison with longitudinal vibration and indirect ultrasonic techniques. Results showed that there was no obvious relationship between the density and the acoustic wave velocity that was obtained from the longitudinal vibration and ultrasonic techniques.

Nondestructive Bending Strength Evaluation of Woodceramics Made from Woody Part of Broussonetia Kazinoki Sieb. - Effect of Resin Impregnation Ratio -

Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for woodceramics made by different phenol resin impregnation ratios (40, 50, 60, 70%) for Broussonetia Kazinoki Sieb. Dynamic modulus of elasticity increased with increasing resin impregnation ratios. There was a close relationship between dynamic modulus of elasticity and static bending modulus of elasticity and between dynamic modulus of elasticity and MOR and between static bending modulus of elasticity and MOR. Therefore, the dynamic modulus of elasticity using resonance frequency mode is useful as a nondestructive evaluation method for predicting the MOR of woodceramics made by different impregnation ratios.

Dynamic Properties of Wood-Plastic Composites

Wood-plastic composites (WPC) , which were made of virgin high-density polyethylene (HDPE) with poplar fibers as filler, were measured by three vibration nondestructive testing (NDT) methods. The values of dynamic Young’s modulus of specimens were measured by different vibration NDT methods, and the values of static bending modulus of elasticity (MOE) were also determined by three point bending test according to ASTM D790-03. The paper analyzed the variability of the dynamic young’s modulus of WPC based on virgin HDPE obtained with different NDT methods, and the correlativity was also estimated between the dynamic Young’s modulus and the static MOE of WPC based on virgin HDPE. These results suggest that WPC can be made of virgin HDPE, and the NDT methods are appropriate to estimate the dynamic Young’s modulus of WPC based on virgin HDPE.

Nondestructive Testing of Wood-Plastics Structural Plates with Stiffener

In order to set up a new effective method for measuring mechanical properties of the wood-plastics structural plates with stiffener, three different nondestructive testing (NDT) methods were used on the specimens with stiffener, which were made of virgin high-density polyethylene (HDPE) with poplar fibers as filler. The values of dynamic Young’s modulus of the specimens were measured by a FFT system. And the values of static bending modulus of elasticity (MOE) were also determined by three point bending test according to ASTM D790-03. The paper analyzed the variability of the dynamic Young’s modulus of specimens with stiffener obtained with different NDT methods, and the correlativity was also estimated between the dynamic Young’s modulus and the static MOE of all specimens. The results suggested that the intensity of the wood-plastics structural plates could be enhanced by stiffener, and the NDT methods could be appropriate to estimate the dynamic Young’s modulus of the wood-plastics structural plates with stiffener.

Stiffness of Douglas-fir lumber: effects of wood properties and genetics

Because stiffness (modulus of elasticity (MOE)) is important for structural wood products, breeders and silviculturists seek to efficiently measure and improve this trait. We studied MOE in a 25-year-old progeny test of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) using field-based tools (ST300 and HM200) to measure stress wave MOE of standing trees and logs. We measured density, static bending MOE, and transverse vibration MOE on 2 × 4s, and density, SilviScan MOE, and SilviScan microfibril angle on small clearwood samples. Bending MOE had moderate to strong phenotypic and genetic correlations with stress wave MOE of trees and logs, transverse vibration MOE of 2 × 4s, and the densities of 2 × 4s and basal wood discs but was weakly correlated with the numbers and sizes of knots. The best lumber grade had the highest bending stiffness and smallest edge knots. Bending stiffness had a strong positive correlation with the density of small clearwood samples and a moderate negative correlation with microfibril angle. Compared with microfibril angle and edge knots, path analyses indicated that density had the strongest direct effect on bending MOE. We recommend that breeders measure and select for stress wave velocity to improve bending stiffness in Douglas-fir. Genetic gains can be increased by including wood density, but genetic selection for fewer or smaller knots will be ineffective.