The box frame is a common structure in modern furniture, especially for cabinets. Accordingly, the joint contact force of the frame is important in evaluating the stability of classified furniture. In this study, a new type of keyed joint was proposed to alter the dovetail joint used in box frame structures. The tensile strength of the dovetail joint and the keyed joint in the frame were evaluated, and the contact forces and failure modes of these two joints were compared. Three levels (T1, T2, and T3) were proposed for the ratio of groove depth (D) to inclined contact surface height (H), under the condition of the same joint spacing and inclination angle considering the effects of keyed joint size on the contact force. Meanwhile, experimental analysis was performed on both sides (S1 and S2) of the dovetail joint. Results showed that the contact force of the joint under the gluing condition decreased in the order of S2 > T2 > T3 > S1 > T1. In terms of failure modes, the keyed joint could be maintained in good condition, whereas failure of the dovetail joint always occurred at the root of the tenon in the S1 direction.

Compressive and tensile strengths were considered for a box connected by dovetail keys under different mortise-and-tenon sizes. Poplar wood modified by melamine resin (MF modified poplar wood) was chosen as the experimental material, and the experimental study was carried out on the box using the concentrated loading method. The results showed that the ratio (T) of hole depth to slope height had a significant effect on the structural strength of the box connected by dovetail keys when other dimensional parameters were the same. When T was equal to 75%, the compression and tensile strength of the box was the highest, and the joint had better recovery and deformation ability. When T` was equal to 50%, the box strength was the worst, and the joint damage was the most serious in both types of loading. In addition, the measurement standard of the displacement was determined through preliminary experimentation. The compression quantity was 8 mm, and the stretching quantity was 5 mm. The latter experiment showed the reliability of the pre-experiment.

Due to the complexity of the geometrical configuration and loading conditions, especially for multiple site damage(MSD). In this paper, four fatigue tests of wide bolted lap joint with MSD inserted along the upper row were carried out under two different constant amplitude loading with marker band. The simultaneous propagation of multiple cracks in the test was monitored continuously by aid of a specially developed image analysis technique. Through fractographic examination, MSD initiation characteristic, crack front shape, and growth course were determined. The results show that the crack initiation stage and early crack growth (up to visible cracks) cover the major part of the fatigue life. When crack grows beyond the bolt heads, the residual lives only have 15%~30% of total fatigue life. The greater the stress level is, the smaller the relative residual life will be. When the crack was linked up for the first time, the residual lives are only 0.7%~2.1%. After the second linked up, fatigue lives are only remaining 0.01%~0.03%.