Finite element modeling of chair frames

Abstract

In this study, chair frames with various stretcher positions were investigated using finite elements analysis. Beech (Fagus orientalis L.) wood has been used as study material. Chair frames are produced using bolts and cross dowels. First, some physical and mechanical properties of the wood materials used in the study have been evaluated. Using mechanical properties found in laboratory conditions, allowable stress values have been calculated. End forces and moments have been found for both the critical sitting position and when the stretcher position is changed. Minimum cross section of the chair elements has been calculated using these values. Structural analysis of the chair frames was conducted using COSMOSWorks software which is a 3D finite element program. Results which are obtained by finite element program and experiments were compared. The generated finite element models have revealed values close to the actual behavior of the chair frames. The highest stresses and deformations resulted in the models which has no stretcher. Use of stretchers will reduce stresses and deformations of the chair frames under load, thus they may reduce material consumption in manufacturing. Keywords: Finite element method, Chair frame, Beech wood