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0000-0003-2873-9547
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Publisher: MDPI AG
Date: 21-02-2019
DOI: 10.3390/F10020194
Abstract: The use of fast-growing plantation eucalypt (i.e., pulpwood eucalypt) in the construction of high-value structural products has received special attention from the timber industry in Australia and worldwide. There is still, however, a significant lack of knowledge regarding the physical and mechanical properties of the lumber from such plantation resources as they are mainly being managed to produce woodchips. In this study, the physical and mechanical properties of lumber from a 16-year-old pulpwood Eucalyptus nitens H.Deane & Maiden resource from the northeast of Tasmania, Australia was evaluated. The tests were conducted on 318 small wood s les obtained from different logs harvested from the study site. The tested mechanical properties included bending modulus of elasticity (10,377.7 MPa) and modulus of rupture (53 MPa), shear strength parallel (5.5 MPa) and perpendicular to the grain (8.5 MPa), compressive strength parallel (42.8 MPa) and perpendicular to the grain (4.1 MPa), tensile strength perpendicular to the grain (3.4 MPa), impact bending (23.6 J/cm2), cleavage (1.6 kN) and Janka hardness (23.2 MPa). Simple linear regression models were developed using density and moisture content to predict the mechanical properties. The variations in the moisture content after conventional kiln drying within randomly selected s les in each test treatment were not high enough to significantly influence the mechanical properties. A relatively high variation in the density values was observed that showed significant correlations with the changes in the mechanical properties. The presence of knots increased the shear strength both parallel and perpendicular to the grain and significantly decreased the tensile strength of the lumber. The results of this study created a profile of material properties for the pulpwood E. nitens lumber that can be used for numerical modelling of any potential structural product from such a plantation resource.
Publisher: MDPI AG
Date: 28-11-2022
DOI: 10.3390/BUILDINGS12122078
Abstract: Fibre-managed E. nitens has the potential to be used as a feedstock for engineered wood products. This resource, however, has a number of strength-reducing features that need to be removed, and the board needs to be re-joint to be useful in greater lengths for timber construction. A common jointing practice is finger jointing. The suitability of the finger jointing technique for this species is crucial to the mechanical properties of the final product. This study was conducted to explore the influence of finger jointing on the stiffness of sawn boards. A strict manufacturing process of docking and re-joining timber boards in the same location without removing strength-reducing features was conducted to compare the stiffness parameters before and after finger jointing with bending tests. A statistical analysis was conducted. The results showed that the frequency of finger joints along the board did not significantly impact the edgewise stiffness however, the average flatwise stiffness of the s les with more finger joints was improved slightly. A 10% increase in the end pressure reduced the tip gap significantly but did not influence the stiffness. The finger joint efficiency was 0.824 for the edgewise stiffness of the s les and 1.034 for flatwise stiffness of the jointed sections.
Publisher: Springer Science and Business Media LLC
Date: 27-07-2013
Publisher: Springer Science and Business Media LLC
Date: 02-11-2015
Publisher: MDPI AG
Date: 26-06-2023
DOI: 10.3390/F14071309
Abstract: Abrasion resistance is an important property for the functional performance and serviceability of timber floors. Although hardness is the conventional criterion used in selecting species for flooring applications, it shows greater variations and restricts the use of low-density species, whereas abrasion resistance could generate a more reliable indication of a product’s surface performance. Eucalyptus nitens is a fast-grown global plantation species extensively available in Tasmania, Australia. Until recently, this material has been perceived as unsuitable for appearance applications such as flooring. This study assesses several engineered flooring prototypes comprised of E. nitens—sawlog managed and fibre-managed resources—compared to an existing market product (E. obliqua and a commercial engineered timber flooring product with UV-cured coating). Tests were performed in accordance with the EN 14354:2016, sandpaper method using Taber abraser and further modified to test flooring prototypes. The highest abrasion resistance was observed in the E. nitens veneer composite product. Fibre-managed E. nitens resulted in the greatest level of abrasion, while sawlog-managed E. nitens was comparable to native regrowth E. obliqua, a commonly used flooring species historically used in Australia. Therefore, the findings from this research suggest there are suitable flooring applications for plantation E. nitens as engineered wood products in some domestic and residential dwellings when compared to existing native products.
Publisher: Elsevier BV
Date: 04-2018
Publisher: Elsevier BV
Date: 06-2019
Publisher: MDPI AG
Date: 15-01-2023
DOI: 10.3390/BUILDINGS13010245
Abstract: In this study, the preliminary serviceability performance of cross-laminated timber (CLT) panels constructed from fibre-managed Eucalyptus nitens (E. nitens) was investigated via bending and vibration tests. Linear four-point bending tests were performed to determine the stiffness and deflection of all CLT panels under serviceability loads. The dynamic response of CLT panels was tested using a basketball and an accelerometer. The fundamental natural frequencies of all tested panels were above the minimum frequency limit (8 Hz) when extrapolated to spans of up to 4.4 m. The configurations of E. nitens CLT panels were based on different modulus of elasticity (MOE) values for each board. Using higher MOE timber boards as the top and bottom layers can significantly increase the serviceability performance of both bending and vibration tests. The same experiments were carried out on two CLT panels made of strength class C24 Spruce-Pine-Fir to compare the serviceability performance of E. nitens CLT. The results demonstrated that E. nitens is a reliable resource for CLT manufacturing, and exhibits better serviceability performance compared to Spruce CLT. This provides more sustainable options for a species traditionally destined for pulp.
Publisher: MDPI AG
Date: 12-01-2023
DOI: 10.3390/BUILDINGS13010208
Abstract: Significant volumes of plantation hardwood are available in Australia to produce value-added engineered wood products such as cross-laminated timber (CLT). To validate the possibility of utilising this available resource, the bending structural properties of plantation Eucalyptus nitens solid board and finger-jointed feedstock were measured. The studied CLT panels produced from finger-jointed lamellas were subjected to bending strength, bending stiffness, rolling shear strength in bending, and pure rolling shear tests to obtain characteristic design values. Solid and finger-jointed timber test results suggested that boards used in longitudinal lamellas have a bending strength of 36.0 MPa and a modulus of elasticity (MOE) of 13,000 MPa. Finger-jointed timber in crossed lamellas presented a declared bending strength of 25.0 MPa. CLT panels showed a bending strength of 24.0 MPa and a rolling shear strength of 2.0 MPa. The experimental results for the CLT panels evidenced that the CLT bending stiffness matches up very well with the modelled results when an MOE of 13,000 MPa is used to describe the stiffness of longitudinal boards. The results presented in this study establish a basis for the commercial use of Australian plantation hardwood CLT in structural applications such as floors and roofs in commercial and residential buildings.
Publisher: MDPI AG
Date: 08-06-2023
DOI: 10.3390/F14061192
Abstract: The performance characteristics of finger-joints as a jointing technique for Eucalyptus nitens is crucial for their use in engineered wood products. This research evaluated the strength of the finger-jointed laminations made from fiber-managed E. nitens. A total of 237 specimens with (117 pieces) and without (120 pieces) finger-joints were sectioned from finger-jointed laminations and tested by bending, tensile, shear, and bearing tests. Bending and tensile tests were paired to identify any correlations. The mean value with finger-joints for bending and tensile were 92.1 MPa and 79.6 MPa, respectively. The presence of finger-joints reduced the strength values. Joint efficiencies in bending and tensile are 0.73 and 0.62, respectively. The distributions of bending and tensile strength were similar for the s les without finger-joints. For the s les with finger-joints, tensile strength was significantly lower than paired bending strength. Shear test results show that the short-span test is inefficient in obtaining the shear strength of fiber-managed E. nitens boards. Meanwhile, the finger-joint efficiency in the bearing is 0.86. The prediction models of lamination’s bending, tensile, and bearing strength were established by non-destructive properties as predictors. Bending strength was highly correlated to the modulus of elasticity value, while tensile and bearing strength were correlated to density. This study obtained promising results on finger-jointed boards from fiber-managed E. nitens suggesting they could be suitable for structural purposes.
Publisher: MDPI AG
Date: 10-11-2020
DOI: 10.3390/F11111189
Abstract: Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata s les and strength in Tasmanian oak s les. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated s les. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.
Publisher: MDPI AG
Date: 03-11-2022
DOI: 10.3390/BUILDINGS12111862
Abstract: Hardness is commonly used to determine the suitability of a timber species for flooring applications. In this study, Janka hardness test is conducted on sawlog managed Eucalyptus nitens and regrowth forest Eucalyptus obliqua sourced from Tasmania, Australia. Plantation E. nitens timber is currently entering the Australian market and the feasibility of using this fast grown species in value added applications such as timber flooring is advantageous. Further to testing Janka hardness on solid timber s les, a regime of engineered timber flooring prototypes consisting of plantation E. nitens top layers, veneers and solid densified E. nitens boards were developed and subjected to Janka hardness test. The results were compared against solid E. obliqua flooring and a commercially available engineered flooring product with Tasmanian Oak top layer. The results showed that Janka hardness of plantation grown E. nitens, and E. obliqua currently available in the market are lower than the values published in the literature. This indicates that the material properties of fast grown plantation timber and regrowth forest material are different to the native forest timber properties published decades earlier. Furthermore, some of the tested engineered flooring prototypes showed similar behaviour to timber flooring products currently in market, suggesting that E. nitens engineered flooring would be suitable for domestic/light commercial flooring applications despite the general conception of unsuitability due to lower densities.
Publisher: Intellect
Date: 10-2016
Abstract: In recent times the Papua New Guinea (PNG) balsa wood industry has increased in global volume and value, offering employment to a significant number of in iduals in East New Britain (ENB) Province. The PNG balsa industry previously relied on China’s renewable wind energy industry for rotor blade manufacturing, which was claimed to be the largest consumer of processed balsa from PNG. Since the Global Financial Crisis (GFC) the Chinese demand for PNG balsa has significantly reduced, resulting in a mass over-supply and under-demand for the PNG resource. A lack of design innovation has added to the current market conundrum and left many smallholders unable to sell their balsa, leading to widespread financial hardship. It has come to the attention of the Australian Centre for International Agricultural Research (ACIAR) and many stakeholders that if there are no new applications for balsa there is no point continuing to grow the resource for a market that is not consuming it. Design innovation generated through research-led industrial design practice is argued as a key element in value-adding to the PNG balsa industry and smallholder businesses. The use of research to inform the design process and generate design innovation is demonstrated through a case study as an attempt to rectify the current over-supply and under-demand.
No related grants have been discovered for Nathan Kotlarewski.