METAL BİRLEŞTİRME ELEMANI VE KAVELALI BİRLEŞTİRME KULLANILARAK ELDE EDİLEN MASİF SANDALYE İSKELETLERİNİN YORULMA PERFORMANSLARININ BELİRLENMESİ

Bu çalışmada, masif ağaç malzeme olarak kayın odunu (Fagusorientalis L.) birleştirme elemanı olarak ise metal birleştirme kullanılarak sandalye iskeletleri üretilmiş ve yorulma performansları belirlenmiştir. Sandalye ayak-kayıtlarında kullanılan metal birleştirme elemanı üç farklı yönde birleştirme yapmaya uygun bir şekilde tasarlanmıştır. Sandalye arkalık ve yan kayıtlarında kavelalı birleştirmeler PVAc tutkalı ile uygulanmıştır. Gerçekleştirilen yorulma testleri sonucunda ayak-kayıt birleştirmelerinde kullanılan metal birleştirme elemanının kabul seviyelerine ulaşamadığı, sandalyenin arkalık kısımlarının ise kabul seviyelerini tamamladığı belirlenmiştir

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

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

Mechanical properties of heat-treated wooden material utilized in the construction of outdoor sitting furniture

Te present study examined the bending moment capacity and rigidity of T-type out-of-plane furniture joints and investigated the efects of heat treatment, wood species, and joint type factors on these joints. Heat treatment method clearly decreased the modulus of rupture (MOR) and the modulus of elasticity (MOE) of selected wood species. Te bending strength of wood samples was reduced afer the heat treatment, decreasing with increased loss of mass. For the heat-treated T-type joints, maximum bending strength values were obtained with Iroko (Chlorophora excelsa ) for both mortise and tenon (MT) joints and blind MT (BMT) joints. Te lowest reduction in bending strength was observed in Ash (Fraxinus excelsior L.) constructed with MT joints and with BMT joints. In general, the BMT joint had higher bending strength than MT joints. Te best rigidity constant (7.21) was obtained with control Iroko BMT joints, while the worst rigidity constant (15.10) was obtained with control Oriental spruce (Picea orientalis L.) MT joints. In terms of heat-treated samples, the best rigidity constant (7.59) was obtained with Black pine (Pinus nigra L.) MT joints, while the worst rigidity constant (14.01) was obtained with Oriental spruce BMT joints. Te maximum performance in joint stifness was determined for Iroko sample BMT joints and Iroko MT joints. Lowest reduction in joint stifness was observed in Scotch pine MT joints and Ash BMT joints. Heat treatment, wood type, and joint type had a signifcant efect on the bending strength of T-type MT post-rail joints. BMT joints produced from heat-treated Iroko wood can be considered as the most durable T-type joint for outdoor sitting furniture construction.Te present study examined the bending moment capacity and rigidity of T-type out-of-plane furniture joints and investigated the efects of heat treatment, wood species, and joint type factors on these joints. Heat treatment method clearly decreased the modulus of rupture (MOR) and the modulus of elasticity (MOE) of selected wood species. Te bending strength of wood samples was reduced afer the heat treatment, decreasing with increased loss of mass. For the heat-treated T-type joints, maximum bending strength values were obtained with Iroko (Chlorophora excelsa ) for both mortise and tenon (MT) joints and blind MT (BMT) joints. Te lowest reduction in bending strength was observed in Ash (Fraxinus excelsior L.) constructed with MT joints and with BMT joints. In general, the BMT joint had higher bending strength than MT joints. Te best rigidity constant (7.21) was obtained with control Iroko BMT joints, while the worst rigidity constant (15.10) was obtained with control Oriental spruce (Picea orientalis L.) MT joints. In terms of heat-treated samples, the best rigidity constant (7.59) was obtained with Black pine (Pinus nigra L.) MT joints, while the worst rigidity constant (14.01) was obtained with Oriental spruce BMT joints. Te maximum performance in joint stifness was determined for Iroko sample BMT joints and Iroko MT joints. Lowest reduction in joint stifness was observed in Scotch pine MT joints and Ash BMT joints. Heat treatment, wood type, and joint type had a signifcant efect on the bending strength of T-type MT post-rail joints. BMT joints produced from heat-treated Iroko wood can be considered as the most durable T-type joint for outdoor sitting furniture construction

AĞAÇ MALZEMEDE YORULMA PERFORMANSI ÜZERİNE ARAŞTIRMALAR

Ahşap, binalardan mobilyaya, spor araç gereçlerinden ambalaj malzemesi olmak üzere birçok alanda yaygın olarak kullanılmaktadır. Çevre dostu ürünlere talep arttığından dolayı, günümüzde ahşaba olan ilgi de artmaktadır. Bu talepten dolayı, diğer malzemeler gibi kullanılıp kullanılmayacağı birçok araştırmaya konu olmaktadır. Bugüne kadar, yorulma ömrü iyileştirme teknikleri birçok endüstride başarılı şekilde uygulanmaktadır. Daha çok gemi yapımında araştırılan yorulma iyileştirme teknikleri bu alana ilgiyi arttırırken, ahşap malzeme ve yorulma ilişkisi üzerine çalışmalar oldukça sınırlı sayıdadır. Dolasıyla bu çalışmanın amacı, ağaç malzemenin yorulma performansı hakkında temel bilgi edinmek ve belirli yüklemeler altında ağaç malzemede oluşan yorulma üzerine yapılan çalışmaları incelemektir

Determination of shear strength and fire performance of plywood supported by woven E-glass fiber

The aim of this study was to determine the shear strength and fire performance of beech (Fagus orientalis) plywood supported (SP) by woven E - glass fiber (WGF). After providing 1.5 mm thickness beech veneers from a commercial company, they were manufactured as five layers. WGFs were placed bottom of the surface layers of plywood. Urea formaldehyde resin which contains 64% solid content was used approximately at a rate of 170 g/m². Adhesive mixture was spread on single surfaces of veneers by using roller brush. Shear strength tests were performed on the bond line 1 (contained WGF) and bond line 2 (not contained WGF) according to TS EN 314-1 as air dried and immersed in water. Fire performance tests were carried out according to ASTM E-69 by using fire tube test. SP samples have increased in reach to maximum temperature approximately three minutes. In bond line 1, shear strength values of control plywood (CP) samples have showed 7% higher shear strength properties than SP samples in air dried. In bond line 2, shear strength values of SP samples which are immersed in water have increased by 45%

The effect of different nanoparticles and open time on bonding strength of poly (vinyl acetate) adhesive

Nanotechnology is one of the major technologies through in this century. Nano particles are an important part of this technology. Properties of many traditional materials can be changed by using the nanoparticles. Open time is one of key processing parameters for adhesive applications. Many adhesion failures are caused by exceeding of the open time. The main objective of this study is to improve the adhesion performance of PVAc adhesive by increasing open time through application of nanoparticles, specifically silicium dioxide (SiO2) and titanium dioxide (TiO2). For this reason, nano SiO2 and nano TiO2 were blended with PVAc at the open time 0, 5, 10 and 15 min. Effect of the nanoparticles and open time was determined by lap shear joint strength tests. Tests were carried out according to DIN EN 302-1. The results indicate that nanoparticles can considerably improve the bonding strength of PVAc at open-time of 5 and 10 min. (C) 2015 Elsevier Ltd. All rights reserved

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.This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under Grant number 112R042. The authors would like to thank TUBITAK to support

The effect of nano-TiO2 and SiO2 on bonding strength and structural properties of poly (vinyl acetate) composites

Polyvinyl acetate (PVAc) is a thermoplastic polymer widely used in the furniture industry. It has many advantages such as easy processing, cheap, biodegradable; but, resistance to water and hot medium is not enough to the application area. In this study, the effect of nano-TiO2 and nano-SiO2 on bonding performance and structural properties of PVAc were investigated. Bonding strength with block shear test and structural properties with thermogravimetric analysis-TGA, X-ray diffraction-XRD, and transmission electron microscopy-TEM of PVAc were determined. The obtained results showed that bonding strength with cooperating both TiO2 and SiO2 for 1\% and 2\% were improved. XRD and TEM results proved to be the homogenously interactions for 1\% and 2\% between nano fillers and matrix. TGA results showed that thermal stability of PVAc blends was largely improved. (C) 2016 Elsevier Ltd. All rights reserved