Numerical Simulation Of Traditional Timber Structure Modelling Based On The Wood Embedded Pressure Characteristics And Friction Mechanism

Inhabited by ethnic minorities in southwestern China,coupled with the diversity of geographical environment and the complexity of topography.Various minorities groups have gradually formed residential buildings with their own national characteristics in accordance with folk customs and local natural environments.Among them,the most typical "Yike yin" column and tie construction have obvious flexible long-period characteristics and higher seismic performance,because of its special material properties and typical joints connection forms by semi-rigid tenonand-mortise joints.Therefore,from material properties to connection forms between components,from theoretical derivation to refined modeling,from model static analysis to dynamic analysis,from single-joint force to multi-joint interaction of bent frames and to the consumption of wooden structures by complex frameworks.It is of great guiding significance to study the energy dissipation and damping performance of wooden structures.This thesis first analyzes the mechanical properties of the wood material from the macro and micro composition of the wood,and points out the essence of the wood’s superior energy dissipation ability.At the same time,the friction behavior based on the adhesion-furrow theory and the embedded behavior based on the Hoffman criterion of the wood are analyzed.Based on the above theory,analyzes the forces of the four joints of the wooden structure,such as the straight mortise-tenon joint,half mortise-tenon joint,stepthrough mortise-tenon joint and dovetail joint,under the action of the bending moment based on the friction mechanism and the embedded compression theory of the wood.The theoretical calculation formulas of M-θ relations of various joints are deduced,and the theoretical models of M-θ relations of joints are obtained through the definition and calculation of characteristic points base on plastic deformation of joints,and the restoring force model of joints is further obtained.Comparing the deduced theoretical model with the results of pseudostatic test of joints,it has a high degree of agreement,indicating that the theoretical model has higher accuracy and better applicability.In order to verify the correctness of the theoretical derivation,the beam element model and solid element model in the large-scale finite element software ABAQUS are used.The sub-program interface is used to introduce the PQ-Fiber model to define the material composition.Uses combination of connector units and theoretical calculation formulas to define joints performance.2 post and lintel wooden bent frames and 2 column and tie wooden bent frames of two-story models are subjected to cyclic displacement loading simulation tests on the basis of considering material properties and joints deformation.The results show that the joints in the frame are not effective at the same time.And their destructive formulas are mostly plastic deformation,shear failure and tear along the grain.The tenon-and-mortise joints have a significant weakening effect on the columns,and can be taken enhanced according to the order in which the joints enter the yield stage.The load-bearing capacity and overall stability of the column and tie wooden bent frame are significantly better than those of the post and lintel wooden bent frame.Finally,uses the finite element software ABAQUS to establish a full-scale twostory house structure of column and tie wooden frame model,and expand modal analysis and dynamic time history analysis.The results show that the semi-rigid tenon-and-mortise joints of the wooden structure and the fixed hinged column foot connection form a large contribution to its long-period flexible characteristics.The tenon-and-mortise joints and large self-weight large roof system are beneficial to reduce the dynamic response of the structure.The synergy between beams and columns of the wooden frame structure is good,and the overall horizontal displacement of the structure is in the range of-20 mm ～ 30 mm,and the model still has a good ability to recover deformation under rare earthquake intensity.