Research On Nonlinear Finite Element Analysis Method Of Timber-concrete Composite Structure

The timber-concrete composite(TCC)beam is composed of concrete slabs and timber beams by shear connectors.Compared with the timber structures,the advantages of TCC structures are higher stiffness,stronger load bearing capacity,better sound insulation,better corrosion resistance and fire resistance.Besides,replacing concrete in tension zone with timber,the following characteristics of TCC structures can be improved,seismic performance and fast-construction.As people pay more attention to environmental protection,the research and applications of TCC structures have broad prospects.Based on the finite element method,the nonlinear analysis method of TCC structures have been investigateed in this thesis.Considering the non-linear nature of the material,the finite element method formulation has been established.Furthermore,a FORTRAN code(FEM-TCC)is developed for TCC structures in this thesis.The results from FEM-TCC,experimental tests and ABAQUS are good agreement with each other.(1)Based on the energy method,the finite element method formulation of TCC beam have been established.A specific analysis of the one-dimensional elasto-plastic problem is carried out.Based on the Newton-Raphson iteration method,the problem of the nonlinear finite element is solved by the several different iteration methods.(2)A static test is conducted on thetcc beam,and the test data is analyzed and summarized to draw an accurate conclusion.In the early stage of loading,the load and mid span deflection shows a linear growth relationship.With the increasing loading capacity,the load and mid span deflection shows a nonlinear growth relationship.When the load is loaded to 75 kN,the composite beam is completely destroyed.(3)The FEM-TCC calculation program is compiled by the FORTRAN code,and a finite element program calculation method is proposed.The results calculated by the FEM-TCC program are basically consistent with the test results.This shows that the program can efficiently and accurately simulate the mechanical behavior of the timber-concrete composite structure.(4)A three-dimensional solid model of the test beam has been established by the finite element calculation software ABAQUS.Specific analysis on the meshing and contact methods of the model is conducted,and the accuracy of the FEM-TCC program is verified.