Document Type : Research Paper
Authors
1 head of the department of E-learning
2 Senior expert, wood and paper science and technology, Civil engineering faculty, shahid rajaee teacher training university
Abstract
In the present study the strength of different kinds of wooden dowels, screws, and ready-to-assemble joints (RTA joints) used in medium density fiberboards (MDF) were assessed and compared for their lateral shear strength. The T-form specimens (20 cm × 8 cm) were comprised of two MDF parts in compliance with ASTM D1761 standard. Five specimens for each treatment were made and a total of 20 treatments were designed; treatments in this study are as follows:Rough as well as smooth dowel joints with 8 and 10 mm diameter, using urea-formaldehyde and poly-vinyl acetate adhesives; Screw joints, sizes 5 and 6, with or without urea-formaldehyde as well as poly-vinyl acetate adhesives; And, different kinds of RTA joints.Results indicate that different kinds of screw joints show the most powerful joints in comparison with other kinds of joints; but there was no significant difference between different kinds of screw joints. Therefore, having economical points of view in mind, screw joints size 5 is recommended to be used without adhesive. The effect of dowel surface as independent variable was statistically significant, while the interaction effect of dowel diameter, adhesive, and quality of dowel surface on lateral shear strength, as well as the independent and interaction effects of two factors of combined wooden dowel along with joint, and adhesive on the strength of RTA joint (that has nuts) were statistically significant.
Keywords
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