Bending properties of particleboard and MDF layers

Holzforschung ◽  
2007 ◽  
Vol 61 (6) ◽  
pp. 717-722 ◽  
Author(s):  
Arnold Wilczyński ◽  
Marek Kociszewski

Abstract The modulus of elasticity in bending and the bending strength of the face and core layer of particleboard and medium density fiberboard (MDF) were determined. Three directions of longitudinal axis of test specimens were considered: the direction of the mat forming, the direction perpendicular to it, and the direction perpendicular to the panel plane. The experiments were carried out on specimens that were prepared with strips of layers separated from the panels and glued into laminated assemblies. The bending properties of the core and face layer of the tested panels differed considerably. The core layer properties were on average more than 4 times smaller for particleboard and almost 3 times smaller for MDF. The relative differences between the bending properties were greater than the differences between the densities of the layers. The bending properties of the layers were almost isotropic in the planes of layers and very strongly anisotropic in the planes perpendicular to layers. The modulus of elasticity of the tested panels was calculated for the axis corresponding to the mat forming direction. The calculations were performed on the basis of the moduli of panel layers and based on the layered system theory. The results were compared with the modulus determined directly for entire panels. The relative difference between the compared moduli was found to be very small for both tested panels.

2019 ◽  
Vol 70 (3) ◽  
pp. 221-228
Author(s):  
Abdullah Istek ◽  
Ismail Ozlusoylu

In this study, the effect of mat moisture content on the physical and mechanical properties of particleboard was investigated. The experimental boards were produced by using 40 % softwood, 45 % hardwood chips, and 15 % sawdust. The formaldehyde resin/adhesive was used in three-layers (bottom-top layer 12 %, core layer 8 %). Multi-opening press was used during manufacturing the experimental particleboards. The physical and mechanical properties of boards obtained were identified according to the TS-EN standards. The optimum core layer moisture content was determined as 6 % and 7 % according to the results, whereas the moisture content of bottom and top layers was 14 %. Under these moisture content conditions, the bending strength was found to be 13.3 N/mm², the modulus of elasticity in bending 2466 N/mm², and internal bonding strength 0.44 N/mm². The optimum bottom-top layer moisture content was determined to be between 13 % and 15 % and 6.5 % for the core layer.


2021 ◽  
Vol 114 ◽  
pp. 70-75
Author(s):  
Radosław Auriga ◽  
Piotr Borysiuk ◽  
Alicja Auriga

An attempt to use „Tetra Pak” waste material in particleboard technology. The study investigates the effect of addition Tetra Pak waste material in the core layer on physical and mechanical properties of chipboard. Three-layer chipboards with a thickness of 16 mm and a density of 650 kg / m3 were manufactured. The share of Tetra Pak waste material in the boards was varied: 0%, 5%, 10% and 25%. The density profile was measured to determine the impact of Tetra Pak share on the density distribution. In addition, the manufactured boards were tested for strength (MOR, MOE, IB), thickness swelling and water absorption after immersion in water for 2 and 24 hours. The tests revealed that Tetra Pak share does not affect significantly the value of static bending strength and modulus of elasticity of the chipboard, but it significantly decreases IB. Also, it has been found that Tetra Pak insignificantly decreases the value of swelling and water absorption of the chipboards.


Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1750 ◽  
Author(s):  
Radosław Mirski ◽  
Pavlo Bekhta ◽  
Dorota Dziurka

This study examined the effects of selected types of thermoplastics on the physical and mechanical properties of polymer-triticale boards. The investigated thermoplastics differed in their type (polypropylene (PP), polyethylene (PE), polystyrene (PS)), form (granulate, agglomerate) and origin (native, recycled). The resulting five-ply boards contained layers made from different materials (straw or pine wood) and featured different moisture contents (2%, 25%, and 7% for the face, middle, and core layers, respectively). Thermoplastics were added only to two external layers, where they substituted 30% of straw particles. This study demonstrated that, irrespective of their type, thermoplastics added to the face layers most favorably reduced the hydrophobic properties of the boards, i.e., thickness, swelling, and V100, by nearly 20%. The bending strength and modulus of elasticity were about 10% lower in the experimental boards than in the reference ones, but still within the limits set out in standard for P7 boards (20 N/mm2 according to EN 312).


2013 ◽  
Vol 744 ◽  
pp. 366-369
Author(s):  
Juan Wei ◽  
Dan Zeng ◽  
Ming Jie Guan

In this paper, the bending properties of bamboo-wood container flooring and bamboo curtain-OSB container flooring were tested and the six-cycle artificial accelerated aging method of ASTM D1037 was conducted to evaluate the aging performance of two kinds of bamboo-wood container floorings. The modulus of rupture (MOR) and modulus of elasticity (MOE) were tested in the longitudinal and transverse directions before and after aging. The results showed that both the bending strength and MOE decreased after aging. The retention ratios of MOR of the bamboo-wood container flooring and bamboo curtain-OSB container flooring were respectively 43.5%, 72.0%, and the retention ratios of MOE were 54.6%, 76.3%. In general, the effect of aging on the bamboo-wood container flooring was larger than that on the bamboo curtain-OSB container flooring.


2000 ◽  
Author(s):  
Liviu Librescu

Abstract This paper deals with a comprehensive geometrically nonlinear theory of shallow sandwich shells that includes also the effect of the initial geometric imperfections. It is assumed that the face-sheets of the sandwich structure are built-up from anisotropic materials layers, whereas the core layer from an orthotropic material. As a result of its features the structural model can provide important information related to the load carrying capacity of sandwich structures in the pre- and postbuckling ranges. Moreover, by using the directionality properties of face-sheets materials, possibilities of enhancing the load carrying capacity of sandwich shells/plates are reached. Selected numerical illustrations emphasizing these features are presented and pertinent conclusions on the beneficial implications of anisotropy of face-sheets and core layer materials upon the load-carrying capacity of sandwich panels are emphasized. Under the present study, the sandwich structure consists of a thick core-layer bonded by the face-sheets that consist of composite anisotropic materials, symmetrically laminated with respect to the mid-surface of the core-layer. The initial geometric imperfection consisting of a stress free initial transversal deflection, will be also incorporated in the study. The loads under which the nonlinear response will be analyzed consist basically of uniaxial/biaxial compressive edge and lateral loads.


2020 ◽  
Vol 110 ◽  
pp. 54-60
Author(s):  
Anita Wronka ◽  
Grzegorz Kowaluk

Selected bending properties of mineral-acrylic solid surface material for furniture construction purposes. The aim of this work was to characterize the bending properties of selected, commercially available panels made with the use of mineral acrylic fillers and thermoplastic matrix (trade names Corian and Staron), with regard to thermal forming. The research showed that when the temperature of the tested materials rises from 20 to 160°C, there is a significant reduction in the value of bending strength (by over 90% for Corian and about 80% for Staron) and the modulus of elasticity (by almost 99% for Corian and by 97% for Staron), which should definitely improve the thermoformability of these materials. Among the two tested materials, Staron is a material that is more susceptible to shape modification at elevated temperatures.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1709
Author(s):  
Jozef Fekiač ◽  
Jozef Gáborík ◽  
Marek Vojtkuliak

The paper is focused on the bending properties of beech plywood made from veneers with perforations. The modification of the plywood was done by the targeted perforations in veneers used. The perforations were rectangular in shape 5 × 30 mm. There was a gap of 10 mm between the perforations (in each direction) and the perforations in the individual rows were shifted by 10 mm relative to each other. Two structures of lightweight plywood were investigated: sheathed (lightweight type 1) with perforated inner layers sheathed with solid veneer and perforated (lightweight type 2) with perforations in each layer. Bending properties were evaluated by three-point bend testing. The results showed decreased bending strength (MOR) as well as decreased modulus of elasticity in bending (MOE) with reduction of weight. Bending strength (MOR) was reduced by 33 to 57% and modulus of elasticity (MOE) by 13 to 43% compared to standard (non-lightweight) plywood. Bendability of lightweight plywood expressed by the minimum bending radius (Rmin) and the coefficient of bendability (koh) point to a slight decrease in bendability by 1 to 35% compared to standard (non-lightweight) plywood. The benefit of the proposed plywood lightweight constructions is weight reduction by 16.5 to 24.4%.


Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1200
Author(s):  
Izabela Burawska-Kupniewska ◽  
Sławomir Krzosek ◽  
Piotr Mańkowski ◽  
Marek Grześkiewicz

The paper presents the partial research results of a mechanical properties study conducted on Scots pine from the Silesian Forestry Area in Poland. The scope of research included the visual strength grading of the timber according to the PN-D-94021:2013 standard, mechanical testing (according to EN 408:2012) and an attempt to assign visuals to the C strength classes. The EN 1912: 2012 standard assigns the visual sorting classes of individual wood species (according to national sorting standards) to the C strength classes introduced by the EN 338: 2018 standard. At the moment, this standard does not assign Polish visual sorting classes (KW, KS, and KG) to C strength classes. The obtained MOE (modulus of elasticity) and MOR (static bending strength) values were corrected according to the EN 384:2018 standard, and their characteristic values were later calculated. On this basis, we proposed a classification of the grading classes determined on the basis of PN-D-94021 into C classes described in EN 338:2018, which is necessary in the process of the transposition of Polish strength grades (KW, KS, KG, and Reject) and the qualification of them in line with EN 1912:2012. The calculated characteristic values of density, MOR and E0 (the modulus of elasticity parallel to the grain) allowed us to assign Polish visual grades KW, KS, and KG to C35, C30, and C20, respectively. The pine timber under research had high physical and mechanical parameters, which translated into high C classes to which the KW, KS, and KG timber categories were assigned.


PERENNIAL ◽  
2006 ◽  
Vol 2 (2) ◽  
pp. 5 ◽  
Author(s):  
Dina Setyawati ◽  
Yusuf Sudo Hadi ◽  
Muh. Yusram Massijaya ◽  
Naresworo Nugroho

Agricultural fibers are currently used as a substituted resource to wood-based products. One of agricultural fibers that has been developed and become a resource for panel products is coir (coconut fiber). The purpose of this study is to evaluate the quality of veneered composite board made of coir and recycled polyethylene (RPE). The target density of board samples was 0.7 g/cm3. The board construction type is core type composite board (three layers). Veneers from Meranti (Shorea sp.) were used as face and back layers and coir was in the core layer. RPE composition was 50% based on coir particle and veneers oven dry weights. Recycled plastics were placed in three layers, 30% on the face and back layers, and 70% in the core layer. The coir sizes were under 1 cm, 1 cm, 5 cm, 10 cm, and 10 cm up (along coir size). The composite board samples were tested by JIS A 5908 – 1994. Each parameter was measured in three replications. The research results obtained are as follows : (1) Veneered composite boards made of coir and RPE fulfill the JIS A 5908 standard in term of density, thickness swelling after 2 and 24 hours of water immersions, modulus of elasticity, modulus of rupture and internal bond, and (2) The coir size did not significantly affect the properties of composite board. Keywords: veneered composite board, coir size, recycled polyethylene


BioResources ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. 3104-3112 ◽  
Author(s):  
Bekir Cihad Bal ◽  
İbrahim Bektaş

In this study, the bending strength and stiffness of laminated veneer lumber (LVL) produced from beech (Fagus orientalis L.), poplar (Populus x euramericana I-214), and eucalyptus (Eucalyptus grandis W. Hill ex Maiden) wood using urea formaldehyde (UF), melamine urea formaldehyde (MUF), and phenol formaldehyde (PF) adhesives were determined. The tests were conducted in the flatwise and edgewise directions. The modulus of rupture (MOR), modulus of elasticity (MOE), specific modulus of rupture (SMOR), and specific modulus of elasticity (SMOE) were calculated. Variance analysis of the bending properties indicated that the effects of the species of tree, the direction of the load, and the type of adhesive were statistically significant. However, according to variance analysis of the SMOR, the effects of the type of adhesive were not significant. The results showed that the type of adhesive did not influence the bending properties of laminated veneer lumber. It can be stated that the differences among groups were due to differences in their densities. The direction of the load and the species of the tree had significant effects on the bending properties.


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