scholarly journals Adhesive Through-Reinforcement Improves the Fracture Toughness of a Laminated Birch Wood Composite

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Wenchang He ◽  
Philip D. Evans

In this paper we test the hypothesis that adhesive through-reinforcement in combination with glass-fibre reinforcement of adhesive bond lines will significantly improve the fracture toughness of a laminated birch wood composite. We test this hypothesis using a model composite consisting of perforated veneer that allowed a polyurethane adhesive to penetrate and reinforce veneers within the composite. Model composite specimens were tested for mode I fracture properties, and scanning electron microscopy was used to examine the microstructure of fracture surfaces. Our results clearly show that through-reinforcement, and also reinforcing adhesive bond lines with glass-fibre, significantly improved fracture toughness of the birch wood composite. Our results also indicate that improvements in fracture toughness depended on the level of reinforcement. Improvements in fracture toughness were related to the ability of the reinforcement to arrest crack development during fracture testing and the fibre bridging effect of glass-fibre in adhesive bond lines. We conclude that through-reinforcement is an effective way of improving the fracture toughness of laminated wood composites, but further research is needed to develop practical ways of creating such reinforcement in composites that more closely resemble commercial products.

2018 ◽  
Vol 53 (12) ◽  
pp. 1705-1715 ◽  
Author(s):  
Yousof M Ghazzawi ◽  
Andres F Osorio ◽  
Michael T Heitzmann

The fire performance of polycarbonate resin and the role of glass fibre reinforcement in altering the fire performance was investigated. Three different fibre weaves with comparable surface density, plain, twill, and unidirectional glass fabrics, were used as reinforcements. E-glass fabrics were solution-impregnated with polycarbonate/dichloromethyl, laid up, and compression-moulded to consolidate the glass fibre reinforced polycarbonate composite. Cone calorimetry tests with an incident radiant flux of 35 kW/m2 were used to investigate the fire properties of polycarbonate resin and its composites. Results showed that glass fibre reinforcement improves polycarbonate performance by delaying its ignition, decreasing its heat release rate, and lowering the mass loss rate. The three fibre weave types exhibited similar time to ignition. However, unidirectional fibre had a 35% lower peak heat release rate followed when compared to plain and twill weave fibres.


Author(s):  
Kaushal Arrawatia ◽  
Kedar Narayan Bairwa ◽  
Raj Kumar

Polymer composites have outstanding qualities such as high strength, flexibility, stiffness, and lightweight. Currently, research is being performed to develop innovative polymer composites that may be used in many operational situations and contain a variety of fibre and filler combinations. Banana fibre has low density compared to glass fibre and it is a lingo-cellulosic fibre having relatively good mechanical properties compared to glass fibre. Because of their outstanding qualities, banana fibre reinforced polymer composites are now widely used in various industries. The primary goal of this study is to determine the effect of the wt.% of banana fibre, the wt.% of SiC, and the wt.% of Al2O3 in banana fibre reinforcement composites on the mechanical and physical properties of banana fibre reinforcement composites. Tensile strength and flexural strength of unfilled banana fibre epoxy composite increased with the increase in wt. of banana fibre from 0 wt.% to 12 wt.%. Further, an increase in wt.% banana fibre drop in mechanical property was observed. It has been concluded from the study that the variation in percentage weight of filler material with fixed amount (12 wt.%) of banana fibre affects the mechanical properties of filled banana reinforcement composites. Optimum mechanical properties were obtained for BHEC5 (72 wt.% Epoxy + Hardener, 12 wt.% banana fibre and 16 wt.% Al2O3).


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 7288-7308
Author(s):  
Fatima Z. Brahmia ◽  
Péter György Horváth ◽  
Tibor L. Alpár

Cement wood composites (CWC) are a popular construction material. Lightweight or panel-wise wood-based buildings have a growing market in central Europe. Requirements and regulations on both the global and national level are forcing continuous developments. This paper summarizes the research achievements in improving the hygroscopic and mechanical properties and shortening the manufacturing time of CWC via pre-treatments and additives. In addition, new perspectives on enhancing its fire resistance properties by using fire retardant pre-treatments are discussed. CWC without any pre-treatment is a material within the B-s1, d0 category of fire resistance. Using fire retardants could upgrade it to the category A1 but the fire retardants should not affect the primary properties of CWC. There are a number of potential fire retardants of wood that may be used, such as phosphorus, boron, and magnesium compounds.


2020 ◽  
Vol 55 (11) ◽  
pp. 4717-4733 ◽  
Author(s):  
Nadiim Domun ◽  
Keith R. Paton ◽  
Bamber R. K. Blackman ◽  
Cihan Kaboglu ◽  
Samireh Vahid ◽  
...  

AbstractIn this study, the effects of adding nanofillers to an epoxy resin (EP) used as a matrix in glass fibre-reinforced plastic (GFRP) composites have been investigated. Both 1D and 2D nanofillers were used, specifically (1) carbon nanotubes (CNTs), (2) few-layer graphene nanoplatelets (GNPs), as well as hybrid combinations of (3) CNTs and boron nitride nanosheets, and (4) GNPs and boron nitride nanotubes (BNNTs). Tensile tests have shown improvements in the transverse stiffness normal to the fibre direction of up to about 25% for the GFRPs using the ‘EP + CNT’ and the ‘EP + BNNT + GNP’ matrices, compared to the composites with the unmodified epoxy (‘EP’). Mode I and mode II fracture toughness tests were conducted using double cantilever beam (DCB) and end-notched flexure (ENF) tests, respectively. In the quasi-static mode I tests, the values of the initiation interlaminar fracture toughness, $$ G_{\text{IC}}^{\text{C}} $$GICC, of the GFRP composites showed that the transfer of matrix toughness to the corresponding GFRP composite is greatest for the GFRP composite with the GNPs in the matrix. Here, a coefficient of toughness transfer (CTT), defined as the ratio of mode I initiation interlaminar toughness for the composite to the bulk polymer matrix toughness, of 0.68 was recorded. The highest absolute values of the mode I interlaminar fracture toughness at crack initiation were achieved for the GFRP composites with the epoxy matrix modified with the hybrid combinations of nanofillers. The highest value of the CTT during steady-state crack propagation was ~ 2 for all the different types of GFRPs. Fractographic analysis of the composite surfaces from the DCB and ENF specimens showed that failure was by a combination of cohesive (through the matrix) and interfacial (along the fibre/matrix interface) modes, depending on the type of nanofillers used.


2002 ◽  
Vol 10 (3) ◽  
pp. 211-218
Author(s):  
Jeng-Shyong Lin ◽  
Sheng-Kuen Wu

In this work, the effect of heat treatment on the fracture toughness of glass fibre reinforced polypropylene was studied. Polypropylene blended with short glass fibres was injection-moulded. The moulded parts were heat treated at 150°C for 30 min. The crack growth resistance curve (R-curve) was measured to evaluate the effect of heat treatment on the fracture toughness, and to determine the stress intensity factor at the point of instability, KR(ins). The fracture surface was examined using scanning electron microscope to analyze the fracture mechanism. The results show that the stress intensity factor at the unstable fracture point KR(ins) increases with the initial crack length.


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