Mechanical properties of oriented bamboo scrimber boards made of Phyllostachys pubescens (moso bamboo) from Taiwan and China as a function of density

Holzforschung ◽  
2018 ◽  
Vol 72 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Min-Jay Chung ◽  
Sheng-Yang Wang

AbstractThe properties of oriented bamboo scrimber boards (OBSB) have been investigated at three density levels (0.8, 0.9, and 1.0 g cm3), while the boards were made from moso bamboo (Phyllostachys pubescens) grown in Taiwan (T-OBSB) and China (C-OBSB). A non-destructive technique (NDT), ultrasonic-wave velocity (Vu) measurements were applied and the dynamic modulus of elasticity (MOEdyn) was calculated. Moreover, static modulus of elasticity (MOE), modulus of rupture (MOR), profile density distribution, internal bond strength (IB), springback (SB), and dimensional stability were determined based on traditional methods. Positive linear relationships between density andVu, MOEdyn, MOE and MOR were observed, no matter if the measurements were done parallel (//) or perpendicular (⊥) to the fiber direction of the OBSBs. Moreover,Vu(//), MOEdyn,u(//), MOE(//), and MOR(//)were higher thanVu(⊥), MOEdyn,u(⊥), MOE(⊥)and MOR(⊥). C-OBSB had slightly lowerVu(//),Vu(⊥), MOEdyn,u(//)and DMOEu(⊥)values than T-OBSB. T-OBSB had higher MOE(//), MOE(⊥)and MOR(//)than C-OBSB, but less MOR(⊥). The profile density distribution of high-density T-OBSB showed singnificant data scattering. The profile density distribution of C-OBSB was homogeneous at all density levels. IB and SB data are directly proportional to density, but water absorption, thickness swelling and volumetric swelling are inversely proportional to density. T-OBSB has better bonding and strength properties, and dimensional stability than C-OBSB.

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 5342-5354
Author(s):  
Chia-Ju Lee ◽  
Min-Jay Chung

Effects of bamboo species, adhesives, and steam-heating treatment (SHT) were examined relative to mechanical properties and dimensional stability of oriented bamboo scrimber board (OBSB) made from makino bamboo (Phyllostachys makinoi Hayata) and moso bamboo (P. pubescens (Mazel)) strips. Results indicated that OBSB produced using makino bamboo culms bonded with water-soluble phenol formaldehyde resin (PF) had significantly higher ultrasonic wave velocity (Vu (//)), tap tone sound velocity (Vt (//)), dynamic modulus of elasticity (DMOEu (//)), and DMOEt (//) than that produced using moso bamboo bonded with water-soluble urea formaldehyde resin (UF) (p < 0.05). The two types of OBSB showed the same trend of DMOEu > DMOEt > modulus of elasticity (MOE). In addition, OBSB made using steam-heated makino bamboo and PF had the largest modulus of rupture (MOR) (210.5 MPa), exceeding that of OBSB made using laminated bamboo timber and wood-plastic composite (WPC). However, OBSB made using steam-heated moso bamboo and UF exhibited the highest screw holding strength (SHS). Improvement in dimensional stability was observed in OBSB manufactured using steam-heated culms. Finally, OBSB glued with UF had lower water absorption, thickness swelling, and volumetric swelling than that glued with PF.


2020 ◽  
Vol 70 (3) ◽  
pp. 370-377
Author(s):  
Cristian Grecca Turkot ◽  
Roy Daniel Seale ◽  
Edward D. Entsminger ◽  
Frederico José Nistal França ◽  
Rubin Shmulsky

Abstract The objective of this article is to evaluate the relationship between the dynamic modulus of elasticity (MOEd), which was obtained with acoustic-based nondestructive testing (NDT) methods, and static bending properties of two domestic hardwood oak species. The mechanical properties were conducted using static modulus of elasticity (MOE) and modulus of rupture (MOR) in radial and tangential directions. Mechanical tests were performed according to ASTM D143 on small clear, defect-free specimens from the two tree species: red oak (Quercus rubra) and white oak (Quercus alba). The MOEd was determined by two NDT methods and three longitudinal vibration methods based on the fast Fourier transform. The destructive strength values obtained in this study were within the expected range for these species. The MOE was best predicted by NDT methods for both species but also had a strong capability to predict MOR.


2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Marta Cristina de Jesus Albuquerque Nogueira ◽  
Victor Almeida de Araujo ◽  
Juliano Souza Vasconcelos ◽  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr

Forest Red Gum eucalypt provides a versatile wood and is converted into different purposes. However, such wood is somewhat limited in structural ends, which highlights the need to exploit this gap through diffusion of mechanical properties of such timber. Obtained results should assist engineers and architects in decision-making for its best building application. This paper studied two physical and fourteen mechanical properties evaluation of Eucalyptus tereticornis at two different moisture contents, following the prescriptions of Brazilian (ABNT NBR 7190: 1997) and North American (ASTM D-143-14: 2014) standard documents. Thus, 1091 repeats were carried out for all properties. By a moisture reduction from 30% to 12%, the bulk density and eleven strength properties statistically showed changes such as modulus of rupture (static bending, parallel and perpendicular compressions), modulus of elasticity (perpendicular compression and static bending), shear stress, tangential cleavage, and parallel and perpendicular hardnesses. Then, the Eucalyptus tereticornis timber could be better usable if is further applied for structural construction uses.


Holzforschung ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jun Li Shi ◽  
Shu Yin Zhang ◽  
Bernard Riedl

Abstract Strength properties and dimensional stability of medium-density fiberboard (MDF) panels made from black spruce (Picea mariana [Mill.] BSP.) 0–20, 21–40, and over 40 year old fiber were studied. An analysis of covariance (ANCOVA) was performed to examine the differences in modulus of rupture (MOR), modulus of elasticity (MOE), and thickness swell (TS) of the three types of panels, while panel density was treated as a covariate in order to adjust the mean values that were partly attributed to panel density. The results indicate that MOR, internal bond (IB), and water absorption of MDF panels made from 0–20 year old fiber, which contained 100% juvenile wood, were significantly superior to those of panels made from 21–40 and over 40 year old fiber; but linear expansion (LE) of MDF panels made from 0–20 year old fiber was significantly larger than that of panels from the other two age classes. The differences in MOR, IB, water absorption, and LE between panels made from 21–40 and over 40 year old fiber were not significant. The comparisons of panel MOE and TS were relatively dependent on panel density due to existence of interactions among the three age groups.


2021 ◽  
Vol 71 (4) ◽  
pp. 391-400
Author(s):  
Kayode Olaoye ◽  
Lawrence Aguda ◽  
Bolade Ogunleye

Abstract Acoustic test methods such as longitudinal vibration have been developed to predict the elastic properties of wood. However, attention has not been shifted to using this method to predict other mechanical properties, especially on Nigeria's preferred, and lesser-used wood species. Thus, we further investigate relationships among mechanical and acoustic properties of selected hardwood species with a view of predicting the mechanical properties of wood from acoustic parameters. Clear wood samples (324) of 20 by 20 by 20 mm3 were collected axially from Albizia adianthifolia, Gmelina arborea, Delonix regia, and Boscia anguistifolia trees, and conditioned before testing. The longitudinal vibration method was adopted to test for the dynamic (acoustic) parameters and properties (fundamental frequency, damping factor, dynamic modulus of elasticity, sound velocity, specific elastic modulus, radiation coefficient, acoustic conversion efficiency, acoustic impedance) while the universal testing machine was used to test for the mechanical properties (static modulus of elasticity, modulus of rupture, maximum compression strength parallel to grain). The damping factor, dynamic modulus of elasticity, and acoustic impedance were the best acoustic parameters that significantly correlated with the static modulus of elasticity (−0.57, 0.81, 0.76), modulus of rupture −0.64, 0.82, 0.85) and maximum compression strength parallel to grain (−0.52, 0.78, 0.84), respectively. There was a significant difference in the mechanical properties with respect to species, thus A. adianthifolia and G. arborea were mechanically better than D. regia and B. anguistifolia for construction or structural purposes. This study revealed that additional new acoustic measures are suitable for inferring mechanical wood properties.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9228-9242
Author(s):  
Ihak Sumardi ◽  
Rudi Dungani ◽  
Ignasia Maria Sulastiningsih ◽  
Deaul Aulia

This study investigated the physical and mechanical properties of bamboo hybrid laminate boards (BHLB) in various fiber directions as a potential wood-replacement structural material. This study used dry bamboo (Gigantochloa apus) processed into thin strips with a thickness of 4 mm and falcata veneer (Paraserianthes falcataria). The BHLB were arranged based on different fiber directions (i.e., perpendicular and parallel) in cold pressing (30 min; 22.2 kgf/cm2) and hot pressing (6 min; 15 kg/cm2). The adhesive used was urea-formaldehyde (UF) resin (glue spread rate of 250 g/m2 and inter veneer 170 g/m2). Physical and mechanical properties were observed to validate the feasibility of preparing BHLB from bamboo strips and falcata veneers. The results showed that the arrangement of the fiber direction affects dimensional stability, MOE (modulus of elasticity), MOR (modulus of rupture), shear strength, and screw withdrawal strength. Falcata veneer as the board core material resulted in lower density, low dimensional stability, and higher water absorption. However, the mechanical properties were not much different and fulfilled the standard for structural use. This study concludes that bamboo can be used for making composite BHLB as an alternative to wood-based composites for structural use.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6550-6560
Author(s):  
Lawrence Aguda ◽  
Babatunde Ajayi ◽  
Sylvester Areghan ◽  
Yetunde Olayiwola ◽  
Aina Kehinde ◽  
...  

Declining availability of the prime economic species in the Nigerian timber market has led to the introduction of Lesser-Used Species (LUS) as alternatives. Their acceptability demands information on the technical properties of their wood. The aim of this study was to investigate the mechanical properties of Ficus vallis-choudae to determine its potential for timber. Three mature Ficus vallis-choudae trees were selected and harvested from a free forest area in Ibadan, Oyo State, Nigeria. Samples were collected from the base (10%), middle (50%), and top (90%) along the sampling heights of each tree, which was further partitioned into innerwood, centrewood, and outerwood across the sampling radial position. Investigations were carried out to determine the age, density, moisture content, impact strength, modulus of elasticity, modulus of rupture, compressive strength parallel-to-grain, and shear strength parallel-to-grain. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel-to-grain, and maximum compression strength parallel-to-grain for Ficus vallis-choudae at 12% moisture content were 20.4 N/mm2, 85.8 N/mm2, 709 N/mm2, 10.7 N/mm2, and 33.6 N/mm2, respectively. The study found the species to be dense with high strength properties in comparison with well-known timbers used for constructional purposes.


Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2632 ◽  
Author(s):  
Marius Cătălin Barbu ◽  
Yasmin Lohninger ◽  
Simon Hofmann ◽  
Günther Kain ◽  
Alexander Petutschnigg ◽  
...  

The aim of this study is to investigate the formaldehyde content and emissions of bark-based insulation panels bonded with three types of adhesives: urea formaldehyde, melamine urea-formaldehyde, and tannin-based adhesives. These panels were produced at two levels of density—300 and 500 kg/m3—and a thickness of 20 mm, and the influence of the adhesive amount and type on the formaldehyde emissions and content was measured. Other mechanical and physical properties such as modulus of rupture, modulus of elasticity, internal bond, and dimensional stability were also scrutinized. With one exception, all the panels belonged to the super E0 classification for free formaldehyde content (perforator value ≤1.5 mg/100 g oven dry mass of panels). The measurements using the desiccator method for formaldehyde emissions assigned all the testing specimens in the F **** category for low-emission panels according to the Japanese International Standards.


2013 ◽  
Vol 744 ◽  
pp. 362-365 ◽  
Author(s):  
Xin Man Chang ◽  
Juan Wei ◽  
Ming Jie Guan

This paper described the influence of different ageing treatments on bending performance of carbonized bamboo scrimber according to three ageing standards (ASTM D1037, BS EN1087-1 and WCAMA). The modulus of elasticity (MOE) and modulus of rupture (MOR) were tested and the fracture morphology of the samples after mechanical test was also analyzed by SEM before and after ageing. The results showed that the average reduction rates of MOE and MOR were respectively 47.48% and 34.98%. In addition, SEM micrographs revealed that the fracture morphology of ASTM and BS EN presented smoother surfaces than WCAMA. The fracture surface of WCAMA was similar to Control but smoother in some parts. This was mainly due to the brittle rupture playing a dominating role in different degrees based on three ageing treatments. In conclusion, the brittleness of material after ageing was intensified leading to the decline of the bending performance.


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