European Journal of Wood and Wood Products最新文献

Wood scrimber is an innovative wood product that offers a viable solution to the shortage of large-sized wood required for structural applications. This study provides comprehensive methodologies for the numerical modelling of structural-scale beams made of scrimber. Initially, a constitutive law based on continuum damage mechanics was developed for this product, integrated into ABAQUS/Explicit as a user-defined subroutine (VUMAT). It was found that the explicit subroutine could accurately capture failure modes, avoid convergence problems, and eliminate the need for specifying mesh-size dependent fracture energy. Subsequently, a calibration approach was proposed for the non-standard specimens to transform material parameters from experimental data to simulation data, addressing the errors between macroscopic specimens and microscopic elements caused by buckling and uneven stress distribution. Furthermore, to model the bending behaviour of a structural-scale scrimber beam, a strategy was proposed to account for the size effect. The results demonstrate that the size effect resulted in a 12.5% reduction in load capacity. The numerical result accounting for the size effect significantly improved agreement with the test data, reducing the maximum error in the ultimate load from 9.8% to 2.5%.

The higher heating value (HHV) and the immediate, final as well as chemical analyses ofdebarked wood for thirty-eight species from the central-western region of Cuba were studied. A new model to compute the HHV based on the elemental composition for all species and for each of the thirty-eight species was proposed. The proposed model for HHV calculation was compared with other available correlations, finding a better fit for the proposal, with a mean deviation of (:pm:2%) and (:pm:4%) in 83.8% and 95.4% of the available experimental data. The best individual fit was obtained for Spondias mombin, L. with a mean error of (:pm:2%) and (:pm:4%) in 89.6% and 98.3% of the available data, respectively, while the weaker fit was computed for Cordia gerascanthoides, H. B. K. with a mean deviation of (:pm:2%) and (:pm:4%) in 80.7% and 90.2% of the available data, respectively. The results show that the model presented in this work is satisfactory, with statistical tests confirming an (:{:text{R}}^{2}>0.9). In all cases, the agreement of the proposed method is good enough to be considered satisfactory for practical design. Given the lack of equal precedents in the literature, this work is considered a contribution to the field of knowledge for the Caribbean region.

This study was to evaluate the feasibility of producing long strands of conventional sizes from post-consumer wood and to assess the impact on the properties of strand boards containing a fraction of such recycled strands. Randomly oriented strand boards were made using varying proportions of recycled wood (0%, 10%, 30%, 50% and 100%) mixed with virgin wood strands. To determine the influence of recycled wood on board properties, we analysed the fractional composition of strands, their wettability, sorption kinetics and cellulose crystallinity for both virgin and recycled wood, and tested various physical and mechanical properties of the resulting strand boards. We then compared the performance of these boards with the requirements of the European standard EN 300 and data from other studies. Boards containing recycled wood exhibited slightly lower but not statistically significant average values for modulus of rupture (MOR) and modulus of elasticity (MOE) compared with the control made from virgin wood. However, the results for internal bond (IB) strength indicated strong adhesion of the recycled strands, attributed to their favourable wetting behaviour. A key benefit of incorporating recycled wood was a significant improvement in the dimensional stability of the boards. In particular, boards made entirely of recycled strands demonstrated a 49.6% reduction in thickness swelling after 24 h of water immersion compared to those made exclusively from virgin wood. The findings indicate that substituting virgin strands with recycled counterparts enables the production of OSB/3 panels using shorter, narrower and thicker strands than standard virgin wood strands.

The sustainable utilization of wood waste is critical for reducing environmental impact and promoting more resource-efficient construction materials. This study investigates the effects of wood flour particle size, wood content, and extrusion parameters—specifically extrusion rate—on the fabrication of wood flour–epoxy composites designed for extrusion-based 3D printing. Through a factorial experimental design, the effects of these parameters on mechanical, physical, and fire-resistant properties were systematically evaluated. Characterization included flexural and compressive strength tests, water absorption, dimensional stability, and fire resistance assessments. Statistical analyses revealed that the epoxy-to-wood ratio is the most influential factor, with a 55:45 ratio yielding optimal results enhanced mechanical strength, improved dimensional stability, and superior fire resistance, while minimizing surface defects. These findings highlight the importance of precise extrusion parameter optimization to produce high-performance composites that incorporate renewable wood resources. The results provide valuable insights for developing partially bio-based materials capable of reducing reliance on petroleum-derived polymers, supporting improved sustainability and performance in construction applications.

Adjusting the wood flour content enables optimisation of wood–plastic composites (WPCs) for different applications. The effect of wood flour content on the machining performance of WPCs is considerable, yet its underlying mechanism remains unclear. In this study, orthogonal cutting experiments were conducted to evaluate the effects of wood flour content, cutting speed, and cutting depth on cutting force and surface characteristics. When the wood flour content increased from 30 to 50%, the higher composite strength resulted in greater cutting forces. However, at 70%, the weakened interfacial bonding led to a reduction in cutting force. Increasing wood content also decreased plasticity and increased brittleness, causing surface damage to shift from burr formation to more severe pit defects, thereby raising surface roughness. Increasing the cutting depth increased the cutting force (243–310%) and surface roughness (24–333%). Increasing the cutting speed also led to increases in cutting force (18–88%) and surface roughness (18–34%). Moreover, with higher wood content, cutting depth contributed more strongly to surface roughness variation, whereas cutting speed contributed more strongly to cutting force variation. These findings clarify the mechanisms of surface damage in WPCs with varying wood flour fractions and provide theoretical guidance for optimising their machining performance.

As an engineered bamboo product, bamboo scrimber has gained increasing attention. The high density and composite structure make it difficult in mechanical processing. In this study, a method of CO₂ laser-assisted sanding (LAS) was applied to investigate the machinability compared with conventional sanding, which was achieved through analyzing laser ablation, sanding power, sanding temperature, surface morphology and profile. V-shaped grooves were generated by the laser ablation, while numerous cavities and charred areas were observed, indicating significant influence on the anatomical structures of bamboo scrimber. Higher specific sanding power and temperature were measured during LAS. This could be attributed to more friction and fluctuation caused by the laser-ablated grooves with 0.5 mm spacing. The laser-induced carbonized layer can be removed by following mechanical sanding. The surface integrity after LAS was composed of ploughed ridges, fiber fractures and hierarchical debonding. It can be inferred that laser pretreatment promotes brittle fracture and interfacial failure, thereby affecting material removal efficiency. LAS produced less upheaval and burrs according to the results of ultimate surface roughness at deeper cutting depth, which showed promise for enhancing bamboo scrimber surface finish despite of the elevated power consumption. This study provided some useful insights into understanding the complex interactions between laser treatment and subsequent mechanical sanding of bamboo scrimber.

A lignin-based wood modification strategy was proposed by impregnating a composite aqueous modifier consisting of allylated lignin (AL), unsaturated phytic acid amine (TEPA-GMA-PA), and N-hydroxymethyl acrylamide (NMA). The system was designed to enhance the dimensional stability, mechanical properties and flame retardancy of fast-growing fir. AL was synthesized through etherification of industrial alkali lignin with allyl glycidyl ether, endowing the lignin with reactive unsaturated sites for crosslinking. Meanwhile, TEPA-GMA-PA was prepared via a ring-opening addition reaction between glycidyl methacrylate and tetraethylenepentamine, followed by neutralization with phytic acid. The successful synthesis of AL and TEPA-GMA-PA was demonstrated by Fourier Transform Infrared Spectroscopy and Nuclear magnetic resonance spectroscopy. The resulting compound modifier was blended with NMA to form an aqueous polymerizable system. Leaching test demonstrated that the modifier underwent in situ polymerization within the wood structure to form water-insoluble macromolecules, reducing the leaching rate to 34.9%. Modified wood exhibited significant mechanical enhancement with 30.8% and 19.6% increases in modulus of rupture and modulus of elasticity, respectively, while maintaining impact strength to natural wood. Flame retardancy improvements were confirmed by cone calorimetry showing 35.6% reduction in total heat release and 7.2% decrease in total smoke production. Furthermore, the limiting oxygen index increased from 22.6 to 34.7%. The proposed strategy provided a new approach for improving of high-value utilization of wood with lignin-based modifier.

This study aimed to determine the levels of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) in two types of creosote-treated railroad ties. The pine ties were at the end of their service life and new beech ties were impregnated with a newer type of creosote. Samples were collected from the outer (within 50 mm of one of the tie edges) and inner (the remainder) portions of railroad ties. PAHs were analyzed by Fourier Transform Infrared (FTIR), High Performance Liquid Chromatography (HPLC), and Gas Chromatography-Mass Spectrometry (GC-MS). Twelve compounds out of sixteen priority PAHs were identified in pine ties, including the carcinogenic benzo-[a]-pyrene and another five that are possibly carcinogenic to humans. In contrast, only six priority PAHs were identified and determined in beech ties impregnated with less toxic creosote, none of which are classified as carcinogenic or possibly carcinogenic to humans. The composition of VOC emissions depends not only on the type of impregnating agent, but also on the type of wood. The emissions from pine wood were dominated by terpenes, while those from beech wood were dominated by PAHs. For both species, PAHs are emitted more from the surface than from the interior of the railroad ties. Although the levels of PAHs are significantly lower in the interior of the ties, their concentration exceeds the limits for waste wood with potential for recycling. For safe recycling of railroad ties, it would be necessary to reduce the level of PAHs by extraction with a suitable solvent.

Balsa wood (Ochroma pyramidale), known for its low density, renewability, and inherently anisotropic cellular structure, is a promising natural candidate for vacuum insulation panel (VIP) core materials. This study systematically investigates the effects of density variation (70-190 kg·m^-3) on the microstructural characteristics, mechanical properties, and thermal behavior of balsa wood, aiming to establish comprehensive structure-property-performance relationships. SEM and optical microscopy analyses reveal that increasing wood density significantly reduces porosity and thickens cell walls, resulting in pronounced enhancements in compressive strength (longitudinally from 3.04 to 11.40 MPa) and thermal stability (with peak decomposition temperature rising from 311.03°C to 345.24°C). Mercury intrusion porosimetry confirms these structural changes, showing a reduction in total porosity from 89.6% to 61.1% and a corresponding narrowing of pore size distribution. Thermal conductivity tests indicate marked directional dependence, where longitudinal conductivity consistently surpasses radial and tangential values, highlighting the crucial role of fiber orientation in heat transfer mechanisms. Upon vacuum encapsulation, thermal conductivity decreases by over 70%, achieving a minimum of 9.88 mW·(m·K)^-1 in the tangential direction at the lowest density tested (70 kg·m^-3), effectively demonstrating the suppression of gaseous conduction. These findings underscore that strategically density-controlled and directionally optimized balsa wood can serve as a high-performance, eco-friendly core material for VIPs, offering significant potential in advancing energy-efficient and sustainable building technologies.

Wood-destroying fungi induce different types of decay, which cause significant reductions in elastomechanical properties of wood when the mass loss is not yet gravimetrically detectable. Particularly difficult to define is incipient decay since the reduction of elastomechanical properties is highly dependent on the heterogeneity of wood species. Early-stage effects of incipient decay on impact behavior remain insufficiently understood. The aim of this study was to clarify how different rot types affect structural integrity in relation to mass loss. Therefore European beech (Fagus sylvatica) and Scots pine (Pinus sylvestris) sapwood specimens were incubated with white-rot (Trametes versicolor), brown-rot (Coniophora puteana) or soft-rot fungi. After incubation, moisture content and relative mass loss were measured. Mass loss (ML) increased linearly over time across all fungi-wood combinations, reaching a maximal reduction of 67% in European beech wood and 39% in Scots pine sapwood with Trametes versicolor. For Coniophora puteana, ML in European beech peaked at 26%, while Scots pine sapwood reached 24%. Soft-rot fungi caused the least degradation reaching 9% ML for European beech wood and 4% for Scots pine sapwood after 99 days. High-Energy Multiple Impact (HEMI) – tests were performed to evaluate the effect of mass loss by fungal decay on the structural integrity of wood, expressed as the Resistance to Impact Milling (RIM). The RIM decreased with increasing ML at early-stages proving the high sensitivity of the test to detect incipient decay, especially with brown rot. The reduction of structural integrity was compared with the reduction of different strength properties of wood depending on the mass loss, where RIM values exhibited less variability compared to other strength properties, suggesting higher measurement stability in case of white and brown-rot decay.