scholarly journals Quasi-static and fatigue performance of bonded acetylated rubberwood (Hevea brasiliensis, Müll. Arg.)

2020 ◽  
Author(s):  
Samuel Oluyinka Olaniran ◽  
Gaspard Clerc ◽  
Etienne Cabane ◽  
Andreas J. Brunner ◽  
Markus Rüggeberg
Keyword(s):  
Cyclic Loading ◽  
Urea Formaldehyde ◽  
Fatigue Behaviour ◽  
Quantitative Information ◽  
Resorcinol Formaldehyde ◽  
Bonding Performance ◽  
Wet Condition ◽  
Dry Conditions ◽  
Timber Products ◽  
Latex Production

Abstract Rubberwood is widely planted for latex production. At the cessation of latex yield it becomes a viable timber source in the wood industry. While good bonding performance of rubberwood has been reported, quantitative information to support this statement is missing. In this study, the tensile shear strength (TSS) and wood failure percentage (WFP) of unmodified and acetylated rubberwood in both wet and dry conditions were examined. Three frequently used adhesives were selected: one-component polyurethane (1C PUR), melamine-urea-formaldehyde (MUF), and phenol-resorcinol-formaldehyde (PRF). Furthermore, fatigue behaviour was analysed for PRF-bonded samples by cyclic loading. Results showed that in dry state, the TSS and WFP of acetylated rubberwood is comparable to the unmodified samples for all adhesives. In wet condition, the performance of bonded rubberwood was improved by acetylation. Cyclic loading revealed comparable fatigue behaviour of bonded unmodified and acetylated rubberwood. This investigation provides first quantitative information on the performance of bonded rubberwood, which can be a valuable input for the production of laminated timber products for structural purposes.

scholarly journals Influence of the adhesive formulation on the mechanical properties and bonding performance of polyurethane prepolymers

Holzforschung ◽  
2011 ◽  
Vol 65 (6) ◽  
pp. 835-844 ◽  
Author(s):  
Sebastian Clauß ◽  
Joseph Gabriel ◽  
Alexander Karbach ◽  
Mathias Matner ◽  
Peter Niemz
Keyword(s):  
Mechanical Properties ◽  
Urea Formaldehyde ◽  
Tensile Tests ◽  
The Other ◽  
Shear Tests ◽  
Resorcinol Formaldehyde ◽  
Bonding Performance ◽  
Atomic Force ◽  
The One ◽  
Adhesive Formulation

Abstract Only small amounts of additives are needed to formulate one-component polyurethane (1C PUR) adhesives for various applications. The current study illuminates the effects of the formulation on the mechanical properties of pure adhesives, on the one hand, and their performance in bonded wood joints on the other. Tensile shear tests on bonded wood joints, tensile tests on adhesive films, and nanoindentation measurements in the interphase region of the bond were performed. Analyses by means of infrared, atomic force, and electron microscopy provided the explanatory basis for the results obtained. Additionally to laboratory made 1C PUR, unmodified commercial 1C PUR, melamine-urea-formaldehyde (MUF), and phenol-resorcinol-formaldehyde (PRF) were tested for comparison. The results obtained confirm that the mechanical properties of 1C PUR adhesives are significantly affected by their prepolymer composition. The adhesive formulation by means of additives, on the other hand, does not affect the mechanical properties but is to a large extent responsible for the bonding performance.

scholarly journals Effects of moisture content on lap-shear, bending, and tensile strength of lap-jointed and finger-jointed southern pine using phenol resorcinol formaldehyde and melamine urea formaldehyde

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 3534-3544 ◽  
Author(s):  
Jian Liu ◽  
Kong Yue ◽  
Feng Wang ◽  
Jinhao Wu ◽  
Zhongqiu Tang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Bending Strength ◽  
Urea Formaldehyde ◽  
Southern Pine ◽  
Resorcinol Formaldehyde ◽  
Bonding Performance ◽  
Lap Shear ◽  
Bonding Shear Strength ◽  
Shear Bending

The bonding performance of the phenol-resorcinol-formaldehyde adhesive (PRF) and melamine-urea-formaldehyde adhesive (MUF) with southern pine as substrates at various moisture contents (MC) was evaluated. The results showed that bonding shear strength with MUF and PRF was negatively related to wood MC, and bonding shear strength with MUF was higher than that of the PRF. The bending and tensile strengths of finger-jointed lumber decreased with wood MC. The bending strength of finger-jointed lumber was affected more by wood than adhesive. However, both wood and adhesive exhibited the same important contribution to the tensile strength.

Bonding performance of melamine-urea-formaldehyde and phenol-resorcinol-formaldehyde adhesives in interior grade glulam

2017 ◽  
Vol 31 (23) ◽  
pp. 2630-2639 ◽  
Author(s):  
Jun Zhou ◽  
Kong Yue ◽  
Weidong Lu ◽  
Zhangjing Chen ◽  
Xiucai Cheng ◽  
...  
Keyword(s):  
Urea Formaldehyde ◽  
Resorcinol Formaldehyde ◽  
Bonding Performance

scholarly journals Potential of Brewer’s Spent Grain as a Potential Replacement of Wood in pMDI, UF or MUF Bonded Particleboard

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 319
Author(s):  
Marius Cătălin Barbu ◽  
Zeno Montecuccoli ◽  
Jakob Förg ◽  
Ulrike Barbeck ◽  
Petr Klímek ◽  
...  
Keyword(s):  
Internal Bond ◽  
Mechanical Performance ◽  
Animal Feed ◽  
Urea Formaldehyde ◽  
Modulus Of Rupture ◽  
Brewer’S Spent Grain ◽  
Beer Brewing ◽  
Removal Of Heavy Metals ◽  
Dry Conditions ◽  
Spent Grain

Brewer’s spent grain (BSG) is the richest by-product (85%) of the beer-brewing industry, that can be upcycled in a plentiful of applications, from animal feed, bioethanol production or for removal of heavy metals from wastewater. The aim of this research is to investigate the mechanical, physical and structural properties of particleboard manufactured with a mixture of wood particles and BSG gradually added/replacement in 10%, 30% and 50%, glued with polymeric diisocyanate (pMDI), urea-formaldehyde (UF) and melamine urea-formaldehyde (MUF) adhesives. The density, internal bond, modulus of rupture, modulus of elasticity, screw withdrawal resistance, thickness swelling and water absorption were tested. Furthermore, scanning electron microscopy anaylsis was carried out to analyze the structure of the panels after the internal bond test. Overall, it was shown that the adding of BSG decreases the mechanical performance of particleboard, due to reduction of the bonding between wood and BSG particles. This decrease has been associated with the structural differences proven by SEM inspection. Interaction of particles with the adhesive is different for boards containing BSG compared to those made from wood. Nevertheless, decrease in the mechanical properties was not critical for particleboards produced with 10% BSG which could be potentially classified as a P2 type, this means application in non-load-bearing panel for interior use in dry conditions, with high dimensional stability and stiffness.

Fatigue Behaviour of Triaxial Braided Composites under Tension-Tension and Compression-Compression Loading

2019 ◽  
Vol 809 ◽  
pp. 23-28
Author(s):  
Florian Herrla ◽  
Helmut Rapp
Keyword(s):  
Cyclic Loading ◽  
Kink Band ◽  
Fatigue Behaviour ◽  
Stiffness Degradation ◽  
Braided Composites ◽  
Material Degradation ◽  
Band Formation ◽  
Compression Loading ◽  
Tension And Compression ◽  
Tension Loading

The fatigue behaviour of [0°/±45°] triaxial braided composites is investigated. Tension-tension and compression-compression loading is chosen to study main damage mechanisms and their effect on the stiffness degradation. In both cyclic loading cases a high stiffness degradation can be observed shortly after the start of cyclic loading. Inter-fibre fractures in the braid yarns with subsequent delaminations are responsible for this behaviour during tension-tension loading. Compression-compression loading leads to kink band formation in the axial yarns favoured by yarn undulations. In consequence of the observed material degradation, S-N curves based on a defined level of stiffness degradation are proposed for fatigue dimensioning instead of load cycles to fracture.

scholarly journals Synthesis of Bio-Oilphenol-Formaldehyde Resins under Alkali Conditions

2020 ◽  
Vol 71 (1) ◽  
pp. 19-27
Author(s):  
Günay Özbay ◽  
Caglar Cekic ◽  
Muhammad Syarhabil Ahmad ◽  
Erkan Sami Kokten
Keyword(s):  
Shear Strength ◽  
Phenol Formaldehyde ◽  
Bonding Performance ◽  
Performance Requirements ◽  
Vacuum Pyrolysis ◽  
Treatment Conditions ◽  
Bio Oil ◽  
Dry Conditions ◽  
Ft Ir ◽  
Pre Treatment

In the present study, bio-oil produced from vacuum pyrolysis of woody biomass has been investigated as a source of chemical feedstock. Bio-based resins were produced using the bio- oil with phenol substitutions ranging from 10 to 30 wt%. The conventional GC/MS analysis was carried out for the evaluation of the chemical composition of bio-oil. TGA, DSC and FT-IR analyses were used in order to characterize the bio-oil-phenol-formaldehyde (BPF) resins. The bonding quality of wood samples bonded with the BPF resins was investigated under different pre-treatment conditions. The highest shear strength was observed for the control samples bonded with the laboratory PF resin. As the amount of bio-oil was increased up to 30 wt%, the shear strength of the samples decreased from 12.08 to 11.76 N/mm2. The bonding performance was not negatively affected by the combination of bio-oil under dry conditions. According to TS EN 12765 standard, the relevant performance requirements for bonded samples under dry conditions must be at least 10 N/mm2. Relating to the standard, all samples bonded with BPF resins obtained the requirements for durability class C1. Under wet conditions, the bonding performance was negatively affected by the addition of bio-oil. However, the BPF resins fulfilled the durability requirements for C1, C2, and C3 specified in EN 12765 (2002).

Fatigue accumulated damage in notched quasi-isotropic composites under high-temperature conditions: A discussion on the influence of matrix nature on the stress energy release rate

2017 ◽  
Vol 52 (17) ◽  
pp. 2397-2412 ◽  
Author(s):  
B Vieille
Keyword(s):  
Cyclic Loading ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Fatigue Behaviour ◽  
Polyphenylene Sulfide ◽  
Plastic Deformations

In order to investigate the contribution of matrix nature to the fatigue behaviour, the purpose of the present work is to establish the correlation between material toughness and macroscopic damage accumulation during tensile cyclic loading in the brittle (C/epoxy) and ductile (C/Polyphenylene sulfide) matrix systems. More specifically, this article presents a fracture mechanics-based approach to compute the strain energy release rate during fracture along with the macroscopic transverse crack growth in fatigue. The knowledge of energy-absorbing processes is important as they are responsible for the toughness of the composite. Woven-ply laminates are characterised by matrix-rich regions which may stop or slow down the growth of fatigue cracks by absorbing the mechanical energy through local plastic deformations at the cracks tip depending on matrix nature. With respect to C/epoxy laminates, the local plastic deformations at the cracks tip are prominent in highly ductile composite systems (e.g. C/Polyphenylene sulfide), and ultimately results in fatigue behaviour virtually independent of the applied stress level under high temperatures T > Tg. To evaluate the influence of matrix ductility and toughness on fatigue damage, a damage variable d based on the measurement of longitudinal stiffness at each cycle was used. A model derived from a Paris law and a fracture mechanics criterion were combined to: (i) evaluate the fatigue crack growth – (ii) compare the changes in the strain energy release rate G and the macroscopic damage d during cyclic loading. Macroscopic damage appears to be well correlated with the strain energy released during fracture.

EFFECT OF WATER ON DUCTILITY AND FATIGUE STRENGTH OF AUSTEMPERED DUCTILE CAST IRON (ADI)

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4571-4576
Author(s):  
TERUTOSHI YAKUSHIJI ◽  
W. GEORGE FERGUSON ◽  
MASAHIRO GOTO
Keyword(s):  
Cast Iron ◽  
Fatigue Strength ◽  
Carbon Steel ◽  
Water Environment ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Ductile Cast Iron ◽  
Tension Test ◽  
Wet Condition ◽  
Austempered Ductile Cast Iron

In order to study the mechanism of decreasing tensile strength and elongation of Austempered Ductile Cast Iron (ADI) in the wet condition, various tension tests and impact tests were carried out. Three point bending fatigue tests were carried out on ADI and annealed 0.55% carbon steel to clarify the influence of water on fatigue strength. The main conclusions are as follow. Embrittlement by water begins when plastic deformation starts in a tension test. The fatigue limit of ADI in water showed a lower value than that in air. The influence of a water environment on fatigue behaviour was similar to that of annealed 0.55% carbon steel. Embrittlement such as that in a tension test was not observed in a fatigue test.

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