Research Articles

Current numerical models for timber components are often limited to single constitutive theories, making it difficult to accurately simulate their complex multi-stage mechanical behavior under diverse service conditions. To overcome this limitation, this study proposes an innovative “multi-model collaborative finite element analysis method.” Guided by the principle of “service-condition matching,” this method dynamically selects and integrates appropriate mechanical models to achieve high-fidelity simulation throughout the entire service life of the component: an orthotropic elastic model is used to reveal the “strong longitudinal but weak transverse” stress distribution under normal loads; the Hill anisotropic criterion captures the evolution of plastic strain as loads approach the yield point; and a viscoelastic model describes the rate-dependent and stress-relaxation behaviors under long-term loading. Results show that the collaborative method effectively elucidates the respective mechanical mechanisms, and Digital Image Correlation (DIC) measurements validate the simulation accuracy. The proposed method provides an innovative and efficient cross-scale numerical tool for timber structures, enabling integrated simulation from short-term safety assessment to long-term performance evolution. This is of great significance for the conservation, performance optimization, and lifespan prediction of historic timber components.

A simple manufacturing strategy was developed to fabricate cross-banded jute stick boards using citric acid (CA). The effects of CA concentrations and pressing temperatures on the physical and mechanical properties of the boards were systematically investigated. Jute sticks were impregnated with CA concentration ranging from 20 to 60 wt% and hot-pressed at 160 to 220°C at a pressing pressure of 5 MPa. Boards treated with 40 wt% CA exhibited the highest modulus of rupture (53.6 N/mm²) and internal bond strength (0.52 N/mm²), while those treated with 60 wt% CA showed superior dimensional stability, with a thickness swelling of 14.7% at a pressing temperature of 200 °C. Fourier transform infrared spectroscopy analysis confirmed the formation of ester linkages between the carboxyl groups of CA and the hydroxyl groups of jute stick components, resulting in strong chemical bonding and interfacial adhesion. Therefore, by optimizing the processing parameters, CA-treated jute stick crossbanded board was successfully developed with enhanced mechanical strength and dimensional stability.

Forty-eight naturally growing Viburnum opulus L. genotypes were collected from the Sarıoğlan, Felahiye, Melikgazi, and Kocasinan districts in Kayseri province, and characterized for morphological and horticultural traits. Fruit width (7.3 to 11.6 mm), fruit length (8.2 to 12 mm), fruit weight (0.3 to 0.8 g), number of fruits per cluster (18 to 111) and cluster weight (10 to 78 g) exhibited significant heterogeneity among the genotypes. Soluble solids content ranged from 7.5% to 11.6% and pH values ranged between 2.6 and 3.7. Oxalic acid content ranged from 221 to 779 mg/100 mL, malic acid from 8.6 × 10³ to 1.4 × 10⁴ mg/100 mL, citric acid from 8.4 × 10² to 2.7 × 10³ mg/100 mL, and ascorbic acid from 544 to 919 mg/100 mL. Total phenolic content was 1.8 × 10³ to 2.0 × 10³ mg/L GAE, total flavonoid content 1.2 × 10³ to 2.0 × 10³ mg/L QUE, and antioxidant activity remained relatively stable, ranging from 83.00% to 85.03% with a mean of 84.42. Principal component analysis (PCA) and hierarchical clustering revealed relationships between morphological and biochemical traits. Correlation analyses indicated strong positive associations between fruit size and cluster characteristics. Phenolic compounds and vitamin C contents are the primary factors determining antioxidant capacity. The results highlight the importance of genetic diversity and provide a foundation for breeding, selection, and sustainable utilization efforts.

Torrefaction is a promising technique for improving the thermochemical characteristics, including calorific value and hydrophobicity, of wood pellets. These properties of torrefied pellets are attributed to the degradation of the cell wall polymers, such as the hemicellulose structure, during the torrefaction process. This study investigated the effects of torrefaction on the chemical components of the cell wall polymers and hemicellulose structure in Japanese cedar. Wood chips were subjected to torrefaction at different temperatures (230 to 500 ºC) and characterized using various techniques, such as thermogravimetric analysis, Fourier transform infrared spectroscopy, and liquid chromatography. The torrefied samples exhibited lower hemicellulose content (glucomannan/galacto-glucomannan (GM/GGM) and arabinoglucuronoxylan (AGX)) than the control sample. In addition, the hemicellulose content of the cell wall decreased with increasing torrefaction temperature. The GM/GGM-to-AGX ratio remarkably changed after torrefaction. As the torrefaction temperature increased, high-molecular-weight assemblies of GM/GGM and AGX shifted toward low-molecular-weight assemblies. Furthermore, the side-chain structure and molecular-weight distribution of AGX decomposed at a lower torrefaction temperature (230 °C), indicating that the AGX polymeric structure had lower thermal stability than GM/GGM. These results provide information concerning the thermal degradation of the behavior of each hemicellulose polymeric structure during the torrefaction.

To investigate the influence of reinforced fiber size on the service performance of wood-plastic composites (WPCs), high-density polyethylene (HDPE) composites were prepared using poplar fibers of seven different sizes. Their bending and impact properties, dynamic thermal mechanical properties, and 24 h creep-24 h recovery performance were analyzed. The WPCs reinforced with 80 to 120 mesh fibers had the worst mechanical properties. The WPCs reinforced with 10 to 120 mesh fibers had the highest bending strength, reaching 28.1 MPa, while WPCs reinforced with 20 to 40 mesh fibers had the greatest bending modulus of 2.73 GPa. The WPCs with 20 to 80 mesh fibers had the highest impact strength, reaching 7.75 kJ/m². Excessively large or small fiber sizes did not benefit the mechanical properties of WPCs. As the temperature increased, the storage modulus of WPCs decreased. Additionally, as the mesh size of wood fibers increased, the loss modulus increased, while the loss tangent gradually decreased, resulting in reduced toughness and more pronounced elastic behavior. Under a 50 N load, WPCs with the mixed mesh fiber outperformed WPCs with single mesh fibers in 24 h creep performance, WPCs reinforced with 20 to 80 mesh fiber showing the best creep resistance.

Analytical and simulation models were used to investigate the formation mechanism and enhancement pathways of green supply chain resilience (GSCR) in customized home furnishing enterprises. A mixed-methods research approach was employed, incorporating both quantitative and qualitative data collection. For the qualitative component, anchored in resilience theory and the Technology-Organization-Environment (TOE) framework, a resilience indicator system was developed that integrates both capability and risk factors, proposing 21 mechanistic hypotheses. For the quantitative component, 179 targeted questionnaires were collected, and partial least squares structural equation modeling (PLS-SEM) was applied using SmartPLS software for factor analysis and hypothesis testing. This was followed by a fuzzy comprehensive evaluation of the case enterprise’s resilience level. Furthermore, a system dynamics model was constructed to simulate resilience development trends under four distinct scenarios. The results indicate that factors such as environmental compliance monitoring maturity and production disruption risks due to adverse events exert the most significant influence on the GSCR of customized home furnishing enterprises.