چكيده به لاتين
Nowadays, the adhesive joints have particular use in many industries especially in the aerospace. However, a variety of loading and environmental conditions cause adhesive joints not to be able to support the needs of some joints. Therefore, the researchers have tried to enhance their mechanical properties by adding variety of materials to the adhesive layer. Synthetic and natural additives have been used to strengthen the adhesive joints. Studies have shown that the use of natural fibers has been considered due to their biodegradability and environmental compatibility in contrast with synthetic fibers. The natural fibers are usually disposed of in the form of scrap in annual pruning. Therefore, their use in the adhesive industry can lead to the production of highly economical and strong products. Due to the abundance of date palm trees in the world, especially in Iran, it is important to use fiber in order to improve adhesive joints. Many researchers have studied the improvement of adhesive strength by date palm fibers in form of balk or composite samples. In this study, the improvement of the strength of single lap adhesive joints (SLJ) by date palm fibers was investigated. Along with this purpose, four parameters including size, alkaline solution concentration, weight ratio and fiber sampling location were investigated by tensile test. According to the results, adding 2 wt% of branch short fibers (0.5 to 2 mm) treated by 6 wt% alkaline solution to the epoxy adhesive layer enhanced the SLJ’s strength up to 140%. In the following, to investigate the micro mechanisms of failure, the fractured surfaces were analyzed. The results show that the date palm fibers can improve the strength of adhesive joints by slowing down the crack propagation, absorbing energy and load endurance.
Keywords: Adhesive joints, natural fibers, date palm fibers, alkaline treatment, failure mechanisms
