Wengang Hu

The fatigue of wood mortise–tenon (M–T) joints commonly results from the looseness of the joints when subjected to long-term cyclic load. It is of critical importance to comprehensively understand the fatigue of M–T joints to know what occurs in M–T joints However, fatigue evolution progression (FEP) of M–T joints has been rarely studied. This study mainly aimed to investigate the FEP of the roughness of mortise (R_M) and tenon (R_T), and the friction coefficient of the non-glued round-end beech wood M–T joint when subjected to cyclic load to provide basic data for numerically modelling the FEP of the M–T joint. The effects of cyclic load amplitude (CLA) (150 N, 200 N, 250 N, and 300 N) and cyclic load count (CLC) (25%, 50%, 75%, and 100% fatigue life) on R_M, R_T, and the friction coefficient were investigated. The results demonstrate that the CLA and CLC have significant effects on R_M, R_T, and the friction coefficient of the M–T joint. The R_M, R_T, and friction coefficient of the M–T joint decrease non-linearly as the CLA and CLC increase, complying with the power law function. The R_M, R_T, and friction coefficient of M–T joints are reduced by a large margin within the CLC of the initial 25% fatigue life, and these reductions decelerate from a CLC of 75% to 100% for all CLAs. The relationships between the friction coefficient and R_M and R_T at each CLA can be well fitted by a quadratic model during FEP. This study provides a new insight to comprehensively understand the FEP of the round-end M–T joint and supplies basic data for numerically modelling the FEP of the M–T joint.

Four mechanical models were proposed to derive formulas predicting the bending moment capacities of layered particleboard under simply supported center-loading. Experimental validation confirmed these models are effective tools for describing the bending moment development process, including proportional limit, yield, and ultimate points. With predicted and experimental ratios ranging from 0.88 to 1.04, Model 4 can reasonably predict the ultimate bending moment capacity of elastic–plastic and bi-modular-layered particleboard materials. Photo-elastic testing revealed neutral axis shifting toward the compressive side, resulting from the face layer’s significantly higher mean modulus of elasticity in compression than in tension. Additionally, the core material above the centerline of PB thickness contributed to tensile resistance. The proposed mechanical models require inputs such as the tensile and compressive strengths and thickness of each layer, accounting for the asymmetric strength profile and neutral axis shifting. The main conclusion was that the bending moment resistance of the particleboard depends on the combined effect of tensile and compressive strengths of all layers. A 3D plot visualized the PB’s mechanical design space, displaying feasible tensile–compressive strength combinations of particleboard layers. This enables determination of optimal strength properties for each layer. For M2 grade particleboard, the most cost-effective design occurred when the face layer reached a 5.38 MPa tensile strength, with the compressive strength ranging between 13.00 and 18.59 MPa.

The Minnan region in China boasts a rich religious culture, giving rise to the distinctive Minnan folk wooden altar table (MFWAT). This study investigated the MFWAT’s artistic characteristics and aesthetic preferences using Kansei Engineering (KE) and eye tracking (ET). The Semantic Differential (SD) method assessed perceptual evaluations, while eye tracking (ET) tests analyzed design elements via heat maps and areas of interest (AOI). Preference ratings complemented the objective measures. Factor analysis indicated that perceptual imagery comprised two principal components: stable-lightweight/dignified-relaxed and simple-complex/ceremonial-practical. Eye movement metrics showed decorative components (AOI-3) attracted significantly more attention than leg-foot (AOI-2) and panel components (AOI-1). Sample GA1 achieved the highest preference score, supporting the eye tracking (ET) findings. Decorative components were the most dominant elements. This integration of subjective and objective methods revealed MFWAT’s aesthetic characteristics and provides references for modern wooden furniture’s innovative design.

This study investigated the influence of wood grain angle (0, 10, 20, 30, 45, 60, 75, and 90 degrees) on acoustic emission (AE) characteristics of southern yellow pine columns subjected to compressive loading. Four AE parameters considered were counts, cumulative counts, count rate, and amplitude. The main conclusion was that AE cumulative counts versus time curves can be characterized with three distinct stages in terms of AE count rates: initiation, growth, and acceleration. The initiation stage had a constant mean count rate of 0.33 counts/s compared to the growth stage mean count rate of 19.10 counts/s, while the acceleration stage had a mean count rate of 608.40 counts/s. Within each stage, count rates increased as grain angle increased from 0 to 30 degrees, then dropped as grain angle further increased to 90 degrees. Maximum AE counts and total cumulative AE counts all increased as grain angle increased from 0 to 30 degrees and decreased as grain angle further increased to 90 degrees. Higher AE amplitudes were observed in the yield and failing stages of tested wood columns according to their stress-strain curves plotted together with their corresponding amplitude-time curves. Maximum amplitude increased as grain angle increased from 0 to 20 degrees, then had a decreasing trend as grain angle increased to 45 degrees, followed by an increasing trend as grain angle increased to 75 degrees. These differences in AE characteristics suggested that AE “signatures” in terms of AE signals do exist for timber materials when subjected to compressive loading.