جستجوی مقالات مرتبط با کلیدواژه « stress carrying capacity » در نشریات گروه « صنایع چوب و کاغذ »

The aim of this study was investigation of the performance of mitered corner joints (L-shaped) reinforced by fibers reinforced polymer (FRP) at maximum stress area under diagonal compression loading. In This way, structural performance of constructed corner joints of two species of beech and fir reinforced by fiber reinforced polymer at polymeric matrix of epoxy with one and two layer of carbon and glass fibers and were investigated. After construction of the mitered joints with wooden dowel and polyvinyl acetate adhesive, the joints were reinforced with FRP composites and then were subjected to diagonal compression loading. Results have indicated that reinforcing layers prevent joint opening, however, failure was occurred at the joint by peeling fibers from wood surface or members fracture near the joints by stress concentration. The results of variance analysis showed that the independent effect of species of joint members and numbers of fibers layer were significant at 95% confidence level. The results showed that use of beech wood in comparison with fir wood, composites reinforced by carbon fibers compared to glass fibers, as well as the use of two layers of fiber compared to 1 layer of fibers, exhibited better performance in constructed joints. The joints made with beech wood and reinforced with 2 layers of composites reinforced by carbon fibers showed the best performance under diagonal compression loading.

Fiber Reinforced Polymer (FRP) has become one of the most popular methods in the reinforced, repair and rehabilitation of structure due to its ease of application and the special physical characteristics. Both destructive and nondestructive assessments have been used to test the characteristics and durability of FRP in order to investigate the condition of the structure. The aim of this research was to investigate the structural performance of corner joint reinforced with fiber reinforced polymer (FRP) composite under diagonal tension load. Constructed joints from two wooden species of beech (Fagus orientalis) and fir (Abies alba), were reinforced with reinforced composites of one and two layer of carbon and glass fibers and then they were tested under diagonal tension load. The miter corner joints were made with wooden pin and polyvinyl acetate adhesive. The fibers lay-up was done manually. Epoxy resin was used as a polymeric matrix. Result of investigation indicated that use of beech wood in comparison with fir exhibited better results. In addition, glass fibers have shown better performance than carbon fiber as reinforcing agents.  Inspection of diagonal tension specimens after failure have indicated that using of FRPs on the surfaces of L-shaped miter prevent joint opening, however, failure was occurred at the joint by increasing of load and vertical displacement and the general wood weakness in tension perpendicular to the grain and shear parallel to the grain at dowels site due to stress concentration. Also the results showed that the miter corner joint made with beech species and two layers of glass fibers had the highest stress carrying capacity.

This study was conducted to evaluate the stress carrying capacity of miter corner joints made with binder of biscuit under diagonal tension and compression loading. Corner joints with the Joint members from two species of beech (Fagus orientalis) and Fir (Abies alba), with 1 to 2 biscuits to size of 10 and 20 and with help adhesives of polyvinyl acetate (PVAc), polyurethane (PU) and urea formaldehyde (UF), they were made and tested. Since wooden pin joint is one of the most commonly included furniture joint, the test specimens were constructed using a pin and PVAc adhesive as a control for comparison with binder of biscuit. The results of analysis of variance showed that the independent effect of the species of Joint members, the size of biscuits, the number of binders and the type of adhesive in both compression and tensile loading is significant at 5% level. The results showed that the stress carrying capacity of the joints made with beech species is higher than that of fir species, and with increasing size and number of biscuits, the stress carrying capacity increases. The stress carrying capacity of the joints made with the polyurethane adhesive was also higher than those made joints with polyvinyl acetate and urea formaldehyde adhesives. The stress carrying capacity of the joints made under compression load was greater than the stress carrying capacity under the diagonal compression and tension load. The highest stress carrying capacity was observed in joints made with beech wood, two binders, biscuit size 20 and polyurethane glue, in both diagonal tension and compression loading.

The aim of this study was to determine stress carrying capacity of doweled corner joints in wood members made with modified resin (polyvinyl acetate) and its comparison with unmodified ones. Joint members were out of European silver Fir (Abies alba) and dowels were made from Beech and poplar woods as variables in this study. Diameter of dowel had three levels in size, namely 6, 8 and 10 mm. The experimental joints were tested under diagonal compression loads. Results have shown that stress carrying capacity of tested joints made with modified glue is more than unmodified ones. Maximum stress capacity was observed in the joints of beech which with 10 mm in diameter dowels. Based on the results, the highest strength was belonging to those joints made with beech wood glued with modified resin containing 10 mm dowel. Furthermore, the lowest strength was belonging to poplar joints made with unmodified resins and 6 mm dowels. The improvement can be due to increased viscosity and controlled penetration of the resin into the wood structure and hence better bonding. Concerning the wood species, beech had the highest stress carrying capacity that it can attributed to its higher density.

This study was conducted to evaluate stress carrying capacity of miter corner joints fabricated with loose tenon with loose tenon under diagonal tension and compression loading. In this study, tests were carried out to determine the effects of dimension of loose tenon A (3.5 × 1 × 0.8 cm) and B (3 × 2 × 0.8 cm), type of adhesives (Polyvinyl acetate (PVA) and polyurethane (PU)) and most commonly used wood species in furniture industry including beech (Fagus orientalis L.) and fir (Abies alba). The results indicate the stress carrying capacity joints under compression is higher compared with that in tension. Stress carrying capacity joints constructed with dimension of loose tenon A was higher than that of those with B. Furthermore, the results have shown that wood species and type of adhesive had significant effect on the stress carrying capacity and performance of joints constructed of Beech wood and PU adhesive were stronger than joints made of Fir wood and PVA adhesive.

The goal of this study was to determine stress carrying capacity of doweled corner joints in framed furniture structures. Joint members were out of European silver Fir (Abies alba) and dowels were made from Beech and Hornbeam woods as variables in this study. Diameter of dowel had three levels in size، namely 6، 8 and 10 mm. Mitered and Butted experimental joints were tested under diagonal tension and compression loads. Results have shown that stress carrying capacity of tested joints under compressive load is more than that of tension one. Also، stress carrying capacity of mitered joints، under both loading type، was more than that of butted joints. Maximum stress capacity under tension load was observed in mitered joints with dowels of hornbeam which were 8 mm in diameter. Under compressive loads، maximum stress capacity was determined in mitered joints fabricated with dowels out of beech which were 8 mm in diameter. With tension loading، changing diameter of dowels from 6 to 8 mm، stress capacity of joint did increase drastically but from 8 to 10 mm، had no significant effects on joints’ capacity. Under compressive load، changing diameter of dowels from 6 to 10 mm had significant effect on capacity of joints. Species of dowel’s wood was not effective in tension، but in compression dowels of beech wood had pronounced improvement on joints’ capacity.