Stiffness Analysis of Wood Chair Frame

This paper presents a stiffness analysis of a statically indeterminate wood-chair side-frame. Numerical calculations are carried out with a ‘linear elastic model’ for orthotropic materials. The mathematical model is solved by a ‘finite element method’. The matrix analysis of structure is carried out by a ‘direct stiffness method’. The frame joints are assumed to be ideally rigid and also as semi-rigid. Horizontal displacement of the top point of the back post is calculated for the most frequently used type of loading for the structure. The results of the calculation indicate that chair side frame becomes stiffer as the position of the stretcher is lowered and/or the stretcher cross section is increased. The results revealed that stiffness of joints in a frame had a considerable impact on the structure deflection. A satisfactory agreement was found between the numerical results and the results obtained by direct stiffness method.