Effect of number of joints and layer arrangements in components on the mechanical strength of chairs made from small diameter poplar

Abstract

The paper describes an investigation into the potential for using small diameter finger jointed and laminated poplar in the manufacture of school chairs in Iran. When compared with solid wood controls, the results were positive although there were marked differences in performance of the various jointing/laminating methods. Failures usually occurred at the glue line.

Whole timber construction: A state of the art review

“…Starting in the 1960's and continuing to the present, governments in forested regions around the world have been increasingly faced with a major forestry challenge: an overabundance of small-diameter trees (100-250 millimetres in diameter), putting forests at increased risk of destructive high-intensity wildfires, disease, and insect attack, while suppressing the growth of trees intended for commercial harvests (Wolfe and Mosely, 2000, Scott et al, 2011, Lim et al, 2013, Bayatkashkoli and Hemmati, 2015, Fuchigami et al, 2016, Erber et al, 2016, Underhill, 2017, Vega et al, 2017, Hiroshima et al, 2018. This overstocking is caused largely by insufficient prescribed low-intensity burning in fire-prone forests, and insufficient early harvests ("thinnings") in planted forests.…”

Investigating the effects of rehabilitation and the use of curved-integrated members on the behavior of chairs

“…Over the past decade, increasing demand for wooden products and adversely decreasing the supply of raw materials has encouraged scientists to present such designs of furniture, which make it possible to expand the length of furniture service life and ultimate strength of chair frames [1][2][3]. The length of furniture service life, usually, decreases due to mechanical failure of even a leg, rail or joint, and/or more often a loose joint [4,5], whereas most of the frames' members have powerfully stayed intact [1]. It seems, therefore, the service life of the furniture could be increased by rehabilitating with materials of higher quality, replacing or recycling damaged parts.…”

“…In the conventional poplar wood chairs, the elements glued together often separate at the glued lanes within the mortise or finger joints [1]. Also, the failure of the custom chair most frequently occurs between the back post and the seat rail, while the use of stretchers and brackets-transmits the failure location to the joints between the back/front post and the side rail.…”