Study On Bending Behavior Of Aluminum Alloy Strengthened Timber Beams

China’s ancient architecture has a long history of building systems dominated by wooden structures,which are also the most widely used and widely used building structural systems.This building remains of high historical and artistic value until now.However,due to its long history,the impact of natural disasters such as typhoons,earthquakes,and fires,as well as the vulnerability of wood to insects and low strength,many ancient buildings have ceased to exist,and the remaining buildings have also been damaged to varying degrees.For these buildings bearing the historical value of our Chinese civilization,we need to promptly repair and maintain them.Currently,steel and fiber reinforced composites(FRP)are widely used in strengthening structures.Aluminum alloy is also a good reinforcement material.Compared to steel structures,the density of aluminum alloy is about one-third of that of steel;The elastic modulus of aluminum alloy is also approximately one-third of that of steel.From the perspective of performance,aluminum alloy and wood structures are more compatible than steel structures.Similarly,the plasticity of aluminum alloy materials will make their reinforcement more beautiful.In order to study the flexural performance of wood beams strengthened with aluminum alloy,Fujian fir was used as the material in the experiment,and 6061T6 model aluminum alloy was selected as the reinforcement material.The reinforcement method of small wood clean-cut specimens(the size of 300mm×20mm×20mm the specimen is as specified in the "Test Method for Flexural Strength of Wood")was studied,with the reinforcement position being the tensile zone and the tensile compression zone,and the connection form being screw connection and glue nail connection;For a wood beam with a full scale specimen size of 2200mm×100mm×150mm,the flexural properties of the aluminum plate thickness of the reinforcement and the spacing of the connectors(wood grain spacing and transverse grain spacing)were studied with full scale specimens.The main tasks were as follows:(1)An experimental study was conducted on the flexural properties of 24 small clean wood specimens in the tensile and compressive regions of the wood reinforcement locations,as well as in the connection forms of screw connections and glue nail connections.Based on the research results,it is recommended that the tensile regions of the aluminum alloy reinforcement locations,and the connection forms be glue nail connections,taking into account the mechanical properties.(2)The study on the flexural performance of 12 full-length wooden beams found that with the increase in the thickness of the reinforcement and the density of the self-tapping screws of the connectors,the integrity of the aluminum plate reinforced wooden beams increased,the utilization rate of wood fibers in the compression area of the wooden beams increased,and the wooden beams changed from tensile brittle failure to ductile failure with significant wrinkles in the compression area of the wooden beams;After strengthening the wooden beam,the bearing capacity,specimen deformation capacity,and initial stiffness are all improved.The influence of the longitudinal and transverse spacing of connectors is different.The longitudinal spacing has a greater impact on the initial bending stiffness,and the transverse spacing has a greater impact on ductility.(3)The three-dimensional solid modeling of the test beam was performed using ABAQUS finite element software,and the reliability of the established finite element was verified through experimental comparison.On this basis,the influence of different parameters on the bearing capacity and deformation capacity of aluminum alloy reinforced wood beams was investigated using the thickness of aluminum plate with reinforcement,the height of beam cross-section,the spacing of self-tapping screws for connectors,and the type and connection form of wood as the variable parameters.Based on the finite element simulation values that change the thickness of aluminum plate with reinforcement and the height of beam cross-section,adjustment factors were introduced to provide corresponding calculation methods for the bearing capacity and deflection of aluminum alloy reinforced wood beams.