Study On Flexural Behavior Of Section Steel Laminated Veneer Lumber Composite Beams

At present,steel and wood are two common building materials in civil engineering.The structures constructed by these two materials alone have many advantages,but they also have their own disadvantages.For example,the design strength of wood structure is low,the wood is easy to crack,the strength will decline over time,the performance is easy to be affected by creep,and in a humid environment,it is easy to be corroded or insect eaten,resulting in performance defects.The steel structure is prone to local bending or overall instability,because with the increase of width thickness ratio,the geometry of steel structure will be more prone to sudden change,resulting in a series of performance defects.Therefore,if the two materials can be combined to form a new composite structure,it is expected to give full play to the advantages of the mechanical properties of the two materials.This paper attempts to combine the two materials and put forward a new type of composite beam:Taking the section steel as the skeleton,the section steel flange and the outer surface of the section steel web are connected with the laminated veneer lumber to form the section steel laminated veneer lumber composite beam.The flexural performance of the composite beam under different parameters is studied,the flexural performance under different parameters is compared,and then the design method suitable for the section steel laminated veneer lumber composite beam is put forward,It provides a design basis for the industrialization and assembly of steel wood composite structure in the future construction industry.The main research contents are as follows:（1）Based on the experimental research on the physical properties of section steel and laminated veneer lumber,this paper obtains the physical properties and performance indexes of section steel and laminated veneer lumber,and carries out the mechanical properties experiment of Italian poplar laminated veneer lumber,which provides an important basis for the calculation and analysis of the theoretical formula of composite beam and the research of finite element numerical simulation.（2）The theoretical calculation formula of bending normal stress of composite composite beams is deduced.Using the direct analysis method,the position of the neutral axis of the composite beam section is determined,and the general formula of the bending normal stress at any point of the cross section of any multi-layer composite beam is established by using the static balance condition.On this basis,the general formula of the bending normal stress of the composite beam with special-shaped section is deduced,and the solution program is compiled by Maple language for example analysis.The theoretical solution is compared with the finite element numerical solution,and the two are in good agreement.（3）ABAQUS finite element software is used to study and explore the key technologies such as finite element modeling,boundary conditions and load loading mode.The nonlinear finite element numerical simulation analysis is carried out for the bending performance of section steel laminated veneer lumber composite beam under the parameters of connection mode,section steel thickness and wood thickness.The results of finite element simulation analysis show that the numerical simulation results of section steel laminated veneer lumber composite beam are good,which shows that the model established by ABAQUS is reasonable and feasible.（4）Considering the structural strength and overall economic benefits,the thickness of medium-sized steel flange of section steel laminated veneer lumber can be 14mm,the thickness of section steel web can be 11mm,and the thickness of web and flange wood can be 40mm.The connection mode between the other two materials can be more reasonable and effective when cementation is selected.The research shows that the mechanical properties of laminated veneer lumber are superior and can meet the requirements of structural materials;The derivation formula of bending normal stress of composite composite beams is accurate and can be used to calculate the bending normal stress of composite beams such as steel wood composite beams;ABAQUS software is used to simulate and analyze the section steel laminated veneer lumber composite beam.The calculated values of the theoretical formula are compared with the calculated values of the finite element numerical simulation,which are roughly consistent,so as to verify the effectiveness of the simulation;The flexural capacity of section steel laminated veneer lumber composite beam is related to the connection mode between materials,the thickness of section steel web,the thickness of flange wood and other factors.The correct design of composite beam parameters can improve the flexural capacity of composite beam.The research results provide a reference basis for the further study of the mechanical mechanism and flexural bearing capacity of steel wood composite beams,and are of great significance for the development of new high-performance green environmental protection composite structures,promoting the assembly and industrialization of building structures,realizing green construction,and finally saving energy and maintaining ecological balance.