MODIFICATION OF ANCIENT WOODEN STRUCTURE MODEL UPON THREE-DIMENSIONAL MECHANICAL ANALYSIS MODEL AND SENSITIVITY METHOD

For an ancient wooden structure, it is difficult to establish an analysis model which have a high degree of agreement with the actual structure because of the discrete nature of materials, of complex connection structures, and of the presence of multiple types of damage. To solve above problems, proposed is a modification method for establishing an ancient building wood structural model upon the three-dimensional mechanical analysis and sensitivity methodology. Constructed is a hybrid element model consisting of beam and column elements and semi-rigid nodal elements reflecting the structural characteristics of key joints, and then established is a three-dimensional mechanical analysis model for the ancient wooden structure. The validation results of the fine numerical model of full entity element show that the analysis model proposed can effectively reflect the force-deformation characteristics of the ideal non-damaged structure. A hybrid element stiffness modification method based on the temperature-strain monitor data is proposed, according to the strong correlation of strain-temperature indicated by the long-term monitor data of the ancient wooden structure. The method takes the three-dimensional mechanical analysis model as the initial model, and the Gauss-Newton iterative method is used to solve the sensitivity equation to obtain the correction value of the stiffness parameter, and then the modified model of ancient building wood structure that can reflect the actual damaged structure is obtained. The effectiveness of the method proposed is verified with numerical simulations. The results show that when the noise level is 5%, the relative error between the modified model stiffness and the actual stiffness is only 3.36%, indicating the method has good noise robustness.