The bending and tension strength of furniture joints bonded with polyvinyl acetate nanocomposites

Furniture is the general name given for the portable equipment used in various human activities such as seating, working and relaxing. They can be a product of design and is considered a form of decorative art. They can widely be manufactured with different adhesives. Biodegradable and biobased adhesives which have no toxic compounds and non-dangerous elements have been selected since the furniture is generally benefited in interior locations. Meanwhile, polyvinyl acetate (PVAc) is a thermoplastic polymer which is widely used in the furniture industry. In this study, tension and bending strength of the furniture joints bonded with polyvinyl acetate adhesives filled with nano-TiO2 and nano-SiO2 were investigated. Three materials; oak (Quercus robur) wood, beech (Fagus orientalis) wood and plywood made with beech veneers were selected, and the joints were prepared by mortise and tenon joints. The results showed that the maximum value for the tension strength and bending strength were obtained to beech wood and oak wood in 2% addition of nano-SiO2 fillers. The minimum values for the tension and bending strength nano-SiO2 were found to plywood and 4% loading

Odun bisküvili köşe birleştirme uygulanmış mobilyanın direnci üzerine bazı faktörlerin etkisi

Bu çalışma, ahşap bisküvi bağlayıcıları ile tasarlanmış mobilya köşe birleştirmelerin direnç ve eğilme momenti üzerine bazı faktörlerin (bisküvi delik merkezleri arasındaki mesafe, bisküvi deliği merkezleri ile levhaların dış kenarları arasındaki mesafe, yükleme metodu, levha tipi ve yapıştırma tekniği gibi) etkilerini değerlendirmek amacıyla gerçekleştirilmiştir. Köşe birleştirmelerin mukavemetlerinin genel olarak yapıştırılmış bisküviden değil yüz ve kenar ile birleştirme elemanlarının bütün olarak yapıştırılmasından kaynaklandığı belirlenmiştir. Yonga levhalardan yapılan tutkallı veya tutkalsız köşe birleştirme dirençlerinin MDF lerden daha yüksek olduğu, kenarları bütün olarak yapıştırılmış birleştirmelerde MDF lerin yonga levhalardan daha dayanıklı olduğu saptanmıştır. Çoklu bisküvili köşe birleştirmelerde, bisküvi merkezleri arasındaki mesafenin artışı (10, 12.5 ve 15 cm) basınç ve çekme direnci değerlerini az miktarda yükseltmiştir. Sonuç olarak kabin tipi mobilya üretiminde dayanıklılığın öncelikli olduğu konstrüksiyonlarda; bisküvi merkezleri arasındaki mesafenin .10 cm yerine 15 cm olarak uygulanmasının bisküvi sayısını ve dolaysıyla işlem sayısını azaltarak kapasiteyi arttırması bakımından daha uygun olacağı belirtilebilir. Sadece bisküvi boşluklarının ve bütün kenarın tutkallandığı köşe birleştirmelerde; bisküvi boşluk merkezleri ile dış kenar arasındaki mesafenin 5 cm olarak uygulanması mukavemeti 6.5 veya 7.5 cm uygulanmalarına oranla artırmıştır. Ancak endüstriyel uygulamalarda kabin tipi mobilya tasarımlarında genellikle tutkalsız (demonte) birleştirme yerine tutkallı birleştirmeler uygulanmaktadır. Bu nedenle bisküvi boşluğu ile dış kenar arasındaki mesafenin 5 cm yerine 6.5 veya 7.5 cm uygulanmasının mukavemet yönünden herhangi bir farklılık yapmayacağı sonucuna varılmıştır.This study was carried out to evaluate the bending moment resistance and stiffness of case-type furniture corner joints constructed with wood biscuits, and to determine the effects on these joints of some factors including the spacing between wood biscuit hole centers, the distance from the center of the biscuit hole to the corresponding outside edge of the board material, the method of loading, the type of composite board, and the gluing technique. The results indicated that corner joint strength comes mainly from the edge gluing of the face and butt member and not from the glued biscuits. Particleboard (PB) glued and unglued edge corner joints were stronger than similar joints constructed with MDF (medium density fiberboard). Glued edge MDF corner joints were suffer than similar joints constructed with PB. Spacing between biscuits of 10, 12.5 and 15 cm on-center in multiple-biscuit corner joints made only small differences in total strength in both tension and compression tests. Therefore, in case-type furniture manufacturing, using 15 cm on-center biscuit spacing instead of 10 cm seems much better in terms of saving time and biscuit joints. Unglued and glued edge joints had greater strength when the distance was 5 cm between the biscuit hole and the corresponding outside edge of the specimen than when it was 6.5 or 7.5 cm with 12.5 cm on-center biscuit spacing. However, in industry most case-type furniture designs have a fixed end instead of a free end joints, and so using a 6.5 or 7.5 cm end distance instead of 5 cm may not make any difference

Lambalı-zıvanalı birleştirme direnci üzerine birleştirme şekil ve boyutunun etkisi

Yakın zamana kadar birleştirmeler ile ilgili detaylar çoğunlukla deneme yanılma metotlarına dayaiı geleneksel bir kapsamda değerlendiriliyordu. Günümüzde mobilya mühendislik tasarımında önceden belirlenmiş dirençte birleştirmelerin sağlanması gerekli görülmektedir. Bu bakımdan, çalışmada nominal olarak aynı şartlarda ve farklı biçimlerde yuvarlatılmış lamba-zıvana, dikdörtgen lamba-zıvana, dikdörtgen zıvanalı/yuvarlatılmış lambalı birleştirmelerin direnç değerleri araştırılmıştır. Ayrıca, her uç biçimi farklı kayıt genişliklerinde ve iki zıvana genişliğinde karşılaştırılmıştır. Sonuçlar dikdörtgen zıvanalı birleştirmelerin hem yuvarlatılmış zıvanalı hem de dikdörtgen zıvanalı/yuvarlatılmış lambalı birleştirmelerden yaklaşık % 15 daha dirençli olduğunu göstermiştir. Ayrıca; birleştirme geometrisi birleştirmelerin direnci üzerinde önemli derecede etkili çıkmıştır. Zıvana genişliği ve uzunluğu arttıkça birleştirmelerin direnci iyileşmiştir. Lambalı zıvanalı birleştirmelerde uç formlarının birleştirme direnci üzerinde fark edilir derecede etkili olduğu görülmüştür. Örneğin, dikdörtgen lambalı zıvanalı birleştirmeler yuvarlatılmış lambalı zıvanalı birleştirmelerden daha dirençli bulunmuştur. Fakat bu durum yuvarlatılmış lambalı zıvanalı birleştirmelerin sandalye konstrüksiyonlarında kullanımını kısıtlamaz, bilakis yuvarlatılmış lambalı zıvanalı birleştirmeler iç gerilmeleri yuvarlatılmış zıvanalara daha yeknesak dağıtarak ayak eiemanlarindaki çatlama riskini düşürürler ve bundan dolayı sandalye iskeletlerinde ön ayak/yan kayıt bağlantılarında kullanılabilirler. Ancak üçüncü tip birleştirme şekli olan dikdörtgen zıvanalı/yuvarlatılmış lambalı birleştirmeler sandalye konstrüksiyonları için tatminkâr bulunmamıştır.Until recently, detailing of joints was largely a matter of tradition, based on trial and error methods. However, in the engineering design of furniture, it is necessary for designers to create joints with a specified strength. This study was undertaken accordingly, to obtain the strength of round tenon/round mortise, rectangular tenon/rectangular mortise and rectangular tenon/round mortise joints assembled under nominally identical conditions with different end configurations. In addition, each end configuration was compared at rail widths, each with 2 widths of tenon. The results showed that rectangular end mortise and tenons are about 15% stronger than both round end mortise and tenons and rectangular end tenons fitting into round end mortise joints. Meanwhile, joint geometry has a significant effect on the strength of those particular joints. As tenon width and length were increased, the strength of the joint was correspondingly improved. The type of mortise and tenon end has an appreciable effect on the breaking strength of the joints as rectangular end mortise and tenons are stronger than round end mortise and tenon joints; however, this does not limit the use of round end mortise and tenon joints in chair construction. It may actually be advantageous to use round end tenon and mortise joints for the front leg/side rail joint in a chair frame as the internal stresses may be more uniformly distributed over the rounded ends of the mortise, thus reducing the risk of splitting the leg member. The third type of construction, with a square end tenon fitting into a round end mortise, was, however, less satisfactory

Design of panel and panel on frame bookshelves and cabinets

The purpose of this thesis is to develop rational design methods for panel and panel on frame constructions used in bookshelves and cabinets, and to investigate the stiffness of four types of construction including frameless, front framed and panel on frame bookcases, and panel on frame wall cabinets. In the case of frameless and front framed constructions, the contribution of the front frame and individual shelves to overall bookshelf stiffness were investigated along with the effect of material type and thickness on stiffness. Results of performance testing were compared with the results of the structural theories. In the case of panel on frame construction, elastic and creep deflection of panel on frame bookshelves at mid-span were investigated first, followed by a study of the stiffness of panel on frame constructions. Contributions of both the panels and the frame and the effect of type of the wood frame properties to overall case rigidity were investigated. Creep deflections of panel on frame wall cabinets were also investigated. The stiffnesses of these cases were compared with the frameless and front framed cases. Actual test results were compared with the results of finite element analyses. Results indicated that for frameless bookcases, panel thickness and inclusion of a front frame significantly increased structural stiffness. Also, each individual shelf contributed about the same amount to overall bookcase stiffness. Classical analysis and finite element results supported the experimental findings. In the case of panel on frame bookcases, round mortise and tenon joints provided relatively good end rigidity. Creep deflection of the shelves averaged 49 to 54 percent of initial elastic deflection; overall creep recovery reached 87 percent of the total shelf deflection. In both panel on frame bookcases and wall cabinets, panels have significant effect on the stiffness of the structure. Panel on frame bookcases are much stiffer than the frameless and front framed bookcases and are not only stiffer but also much lighter. Finally, results of the studies lead us to conclude that strong and durable panel on frame bookcases and wall cabinets can be produced by means of simple techniques

Section modulus of corner joints in furniture frames as engineering design criteria for their efficient construction

Since joints are often the weakest points in furniture construction a detailed analysis of the factors influencing their load bearing capacity and its effectiveness in utilizing the full strength of the wood is reported here. As a result of this analysis, the value of the ratio of the section modulus of the joint W-p to the section modulus of the element W-e has been established as the criterion for determining the correctness of construction based on material strength and production technology. The value of the ratio W-p/W-e indicates the percent to which utilization of the full strength properties of individual elements in the joints outlined. The value of the ratio W-p/W-e is the rational criterion for assessing the correctness of the joint construction and it enables better use of the mechanical properties of the wood used in the joint. Moreover, it makes possibilities to specify the mechanical factors of joints applied in joinery constructions. (C) 2010 Elsevier Ltd. All rights reserved

Evaluation the effects of edge banding type and thickness on the strength of corner joints in case-type furniture

Edge banding is used to cover the exposed sides of wood materials such as plywood, particleboard or medium-density fiberboard, giving the appearance of a solid (or more valuable) material. This study was carried out to determine the effects of the edge banding material, namely polyvinyl chloride (PVC), melamine and wood veneer, thickness of edge banding material (0.4, 1, and 2 mm), and wood composite panel type on the diagonal compression and tension strength properties of particleboard surfaced with synthetic resin sheet (LamPb) and MDF surfaced with synthetic resin sheet (LamMDF). The diagonal tension strength was greater than the diagonal compression strength of all L-type corner joints. Samples with edge banding gave higher diagonal tension and compression strength than control samples. LamMDF corner joints were stronger than LamPb corner joints. As for the type of edge banding, melamin type edge banding material gave more diagonal tension and compression strength than others. The lowest tension and compression strength was obtained in PVC edge banding material. There were significant differences in strength in terms of type of edge banding and wood composite panel material. A clear relationship between edge banding thickness and strength could not be determined. As case furniture constructions are under diagonal tension and compression forces, spline joint using 0.4 mm melamine edge banding can be recommended as the most robust corner joint type for case furniture produced from LamMDF panels. (C) 2009 Elsevier Ltd. All rights reserved