We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon （M＆amp;LT） furni-ture joints under uniaxial bending loads, and determined the effects of loose ...We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon （M＆amp;LT） furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length （30, 45, 60, and 90 mm） and loose tenon thickness （6 and 8 mm） on bending moment capacity of M＆amp;LT joints constructed with polyvinyl acetate （PVAc） adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element （FE） software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.展开更多
The mortise-tenon joint is an important hub transmitting and distributing external loads for load-bearing components(beams,columns et al.)in the ancient-timber frame structure system.However,the conventional steel hoo...The mortise-tenon joint is an important hub transmitting and distributing external loads for load-bearing components(beams,columns et al.)in the ancient-timber frame structure system.However,the conventional steel hoop reinforcement methods often insert wood screws into the timber components.When the reinforced joint rotates greatly,the anchoring failure of the screws will cause damage to the timber joint.To solve this problem,this study proposes a detachable and replaceable non-destructive flat-steel jacket reinforcement method in which horizontal flat steel is placed in the center of the joint,and the bolt is extended to the outside of the timber beam.Nine 1:3.52 scaled straight-tenon joint specimens were subjected to monotonic loading of beam ends,including three unreinforced reference joints,three joints with flat-steel jacket and three carbon fiber-reinforced plastic(CFRP)reinforced joints.The mechanical behaviors of the novel joints with flat-steel jacket were experimentally studied by comparing with those of the joints without strengthening and retrofitted with CFRP,based on the failure modes,the initial stiffness,the ultimate bearing capacity,and the moment-rotation relationship curves.Results indicated that the mortise-tenon joints reinforced with flat-steel jackets maintain the original semi-rigid properties of the unreinforced mortise-tenon joints and can effectively prevent the tenon from pulling out.The initial stiffness and ultimate bearing capacity were improved markedly.The column and beam of the reinforced joints remain intact providing the reference for the practical application of joints reinforcement.The mortisetenon joints reinforced with CFRP lose the semi-rigid properties of the unreinforced tenon-mortise joints.The joints reinforced with CFRP have the largest initial stiffness,while the unreinforced joints have the lowest stiffness.The initial stiffness of the proposed joint is in between the joints reinforced with CFRP and unreinforced joints.The ultimate bearing capacity of the joints reinforced with flat-steel jacket is larger than the other two joints,whereas the unreinforced joints have the lowest ultimate bearing capacity.展开更多
文摘We studied the effect of loose tenon dimensions on stress and strain distributions in T-shaped mortise and loose tenon （M＆amp;LT） furni-ture joints under uniaxial bending loads, and determined the effects of loose tenon length （30, 45, 60, and 90 mm） and loose tenon thickness （6 and 8 mm） on bending moment capacity of M＆amp;LT joints constructed with polyvinyl acetate （PVAc） adhesive. Stress and strain distributions in joint elements were then estimated for each joint using ANSYS finite element （FE） software. The bending moment capacity of joints increased significantly with thickness and length of the tenon. Based on the FE analysis results, under uniaxial bending, the highest shear stress values were obtained in the middle parts of the tenon, while the highest shear elastic strain values were estimated in glue lines between the tenon sur-faces and walls of the mortise. Shear stress and shear elastic strain values in joint elements generally increased with tenon dimensions and corre-sponding bending moment capacities. There was consistency between predicted maximum shear stress values and failure modes of the joints.
基金This research was funded by the National Natural Science Foundation of China No.51908291Nanjing Forestry University Youth Science and Technology Innovation Fund No.CX2019002.
文摘The mortise-tenon joint is an important hub transmitting and distributing external loads for load-bearing components(beams,columns et al.)in the ancient-timber frame structure system.However,the conventional steel hoop reinforcement methods often insert wood screws into the timber components.When the reinforced joint rotates greatly,the anchoring failure of the screws will cause damage to the timber joint.To solve this problem,this study proposes a detachable and replaceable non-destructive flat-steel jacket reinforcement method in which horizontal flat steel is placed in the center of the joint,and the bolt is extended to the outside of the timber beam.Nine 1:3.52 scaled straight-tenon joint specimens were subjected to monotonic loading of beam ends,including three unreinforced reference joints,three joints with flat-steel jacket and three carbon fiber-reinforced plastic(CFRP)reinforced joints.The mechanical behaviors of the novel joints with flat-steel jacket were experimentally studied by comparing with those of the joints without strengthening and retrofitted with CFRP,based on the failure modes,the initial stiffness,the ultimate bearing capacity,and the moment-rotation relationship curves.Results indicated that the mortise-tenon joints reinforced with flat-steel jackets maintain the original semi-rigid properties of the unreinforced mortise-tenon joints and can effectively prevent the tenon from pulling out.The initial stiffness and ultimate bearing capacity were improved markedly.The column and beam of the reinforced joints remain intact providing the reference for the practical application of joints reinforcement.The mortisetenon joints reinforced with CFRP lose the semi-rigid properties of the unreinforced tenon-mortise joints.The joints reinforced with CFRP have the largest initial stiffness,while the unreinforced joints have the lowest stiffness.The initial stiffness of the proposed joint is in between the joints reinforced with CFRP and unreinforced joints.The ultimate bearing capacity of the joints reinforced with flat-steel jacket is larger than the other two joints,whereas the unreinforced joints have the lowest ultimate bearing capacity.
