Contact Properties Of Mortise-Tenon Joints In Ancient Timber Buildings

The ancient buildings have its irreplaceable value in historical and cultural.It is very necessary to study the ancient timber buildings because it occupied a large share in the existing ancient buildings.In the ancient timber building,the main connection mode is mortise and tenon joint.This kind of joint making ancient timber building has good seismic performance by the contact area between the mutual extrusion and friction under the action of earthquake.Therefore,study the contact properties of mortise-tenon joint is significant.The paper presented a contact model based on traditional contact theory.In the model,the contact behaviors such as tangential friction coefficient and normal contact stiffness have been studied,and these two contact behaviors are related to the wood surface morphology parameters and material properties.All of these parameters are also investigated experimentally in the paper.The friction constitutive in the contact model has been realized by writing a friction subroutine of ABAQUS in FORTRAN language.In the paper,two kinds finite element model have been established,one was normal in which the contact interaction property has been set as constant friction coefficient in tangential direction and hard contact in normal direction,the other one used the contact model.In the FEM with contact model,the tangential contact property was user defined that can call the friction subroutine and the normal contact property was defined a contact stiffness coefficient.In the normal FEM,friction coefficient was equal to 0.5.Compared the test result and the analysis of two kinds FEM simulate result.Above three showed obvious rheostriction in the load-displacement hysteresis curve.Their bearing capacity and stiffness were in good agreement.In order to contrast the difference between the FEM used contact model and the normal FEM,the paper comparative analysised their performance from the following aspects,the friction dissipation,contact state,contact stress and contact force.It was found that all aspects have non-ignorable distinguish.In more meticulous demand analysis,apply the contact model established in this paper is more reasonable.