Determination of the impact of creeping of furniture joints on their rigidity

The study presents research results on the effect of creeping on changes in the rigidity of selected joints used in constructions of upholstered furniture, expressed as the substitute modulus of elasticity Ez. The modulus was calculated analytically for this purpose using the Maxwell–Mohr constitutive equation. In addition, actual runs of creeping curves were determined and a theoretical model well describing the obtained results was selected. Simultaneously, a detailed statistical analysis was carried out. It was found that creeping exerted a significant impact on the mechanical quality of the examined joints by reducing their substitute modulus of elasticity by 11%–16%. This modulus can be employed in numerical calculations using the finite elements method.