STRUCTURAL ANALYSES OF WOODEN CHAIRS BY FINITE ELEMENT METHOD (FEM) AND ASSESSMENT OF THE CYCLIC LOADING PERFORMANCE TN COMPARISON WITH ALLOWABLE DESIGN LOADS

Abstract

Tests were carried out to investigate the cyclic loading performance of chairs constructed of Scotch pine (Pinus sylvestris) and Oriental beech (Fagus orientalis). Totally, 30 real size chairs were constructed and assembled with polyvinyl acetate adhesive. Chairs were tested under 3 cyclic loading directions; namely, front to back, back to front, and backrest according to American Library Association (ALA) specifications, and obtained loading performances of chairs were crosschecked with allowable design load levels. Additionally, specimens were analyzed as structures by using the finite element method in order to obtain axial, shear, and bending stresses acting on each member under loadings and compare these values with design stresses. As a result, it was concluded that finite element method analyses achieve reasonable estimates for strength performances and failure behaviors of chairs. Depending on allowable design loads by American Library Association; chairs constructed of beech could meet the medium service for front to back and back to front loading, while heavy service for backrest loading. In the case of pine chairs; they could meet the medium service for front to back and back to front loading, while light service for backrest loading.