Research On Layered Finite Element Analysis Method Of Timber-Concrete Composite Structure

Since the new century,green planning,green design and green construction in the field of civil construction have been further promoted.The development and application of Timber-Concrete composite(TCC)structure has more prospect.As a new type of composite structure,the complex mechanical,difficult numerical analysis and much limitation in TCC structure.In order to explore the distribution law of internal stress and strain on the section of timber beam,the Layered finite element method of TCC structure has been studied in this paper.Based on the element of TCC beam,the Layered finite element model of TCC beam is established by introducing the Layered theory.The material nonlinearity of TCC beams is studied.And the distribution of stress and strain in the section of timber beam is obtained.The main work of this paper is as follows:Firstly,using the deformation theory of composite beams with elastic connection,the section conversion of different types of composite beams is carried out.The analytical solutions of section strain and curvature under different load cases are obtained.Secondly,on the basis of the energy principle,the linear stiffness matrix of TCC beam element is derived by considering the deformation energy of concrete slab and timber beam and the elastic potential energy of spring element.The finite element formulation of TCC beam is established by using the finite element method.Thirdly,based on the element of TCC beam,the Layered finite element model of TCC beam is established by introducing the Layered theory.In this model,the non-linear constitutive relation of concrete and timber is considered,the linear stiffness matrix of composite beam unit is modified,the non-linear stiffness matrix of composite beam unit is obtained.The finite element solution method of material non-linear problem of composite beam is carried out.Furthermore,through the Layered finite element model of TCC beam,the corresponding finite element program is compiled by using FORTRAN.The calculation results are in good agreement with the test results.The finite element method and calculation program are verified to be correct.